Friday, May 24, 2013

Statistics 101: Two-Sample Hypothesis Testing

I am slowly going through Statistical Analysis with Excel book and I am making simulation worksheets to understand the concepts.

I have created the the worksheet with two populations and two pulled samples to get my mind on standard error of the difference between means which is used in Two-Sample Hypothesis Testing. I have used both Z-Test (when populations variances are known) and T-Test (when we don't know population data).

You can download the Excel workbook HERE. The file is around 11MB due population data (are we simulating or not? :) )

Tuesday, May 21, 2013

Statistics 101: Central Limit Theorem Simulation in Excel

Understanding Central Limit Theorem is of EXTREME importance in statistics. This concept usually sets the boundary line between people who understand statistics and people who don’t.

What is confusing about this topic is usually terminology – mean of sampling distribution of the mean, standard deviation of the sampling distribution of the mean – you get the point. What I wanted to do is to make this thing easier to comprehend by using Will Hopkins approach by using simulations. Will Hopkins created great and must read series of spreadsheet designed to help out lost souls (like me) comprehend basic statistic concepts. You can find those spreadsheets and description HERE.

What was lacking in Hopkins spreadsheets was simulation of central limit theorem. Thus I have created this spreadsheet using his famous template. I suggest watching lectures by Khan Academy and then playing with the spreadsheet. Modifying various numbers and seeing how that affects the output might give you deeper understanding of this fundamental concept behind all inferential statistics. I believe I still lack some of the nuts and bolts to get, so I might listen to my own advice and check the Khan videos.

If you find any errors please be free to notify me.
Click HERE to download the Excel spreadsheet.

Saturday, April 27, 2013

Rant: Program design software and some more….

I will be honest here: I F*CKING HATE PAPERWORK. My ultimate goal is to make things as simple as possible and to focus on the most important aspects of coaching (well, coaching) instead of losing precious time and energy on B.S. And paperwork is B.S.

I have been using Excel extensively lately – from designing the yearly periodization chart, to keeping track of performance scores and player profiles, to attendance sheet and workloads monitoring, along with wellness scores, power output and designing team and individual workouts. Managing all of them demands a lot of time – so much that I am getting enough with it. There has to be simpler solution. At least I hope so. And hopefully without the need to spend a lot of \$\$\$.

Managing Databases like this in Excel is clunky, if that is a right word. It is really hard to ‘connect’ individual databases without some VB code and without Excel crushing or slowing down. I am actually thinking about learning Access and building better DB (Database, not dumbbells) with queries, user forms and reports. But Hell – I am strength and conditioning coach, not a damn programmer.

I believe that coaching should be 80% actual coaching and planning and 20% paperwork. Now it is vice versa unfortunately for most of the coaches.

Suppose you need to design a program for a friend that asked for one to get in “shape”. Sure thing – it is pretty simple: you have a general idea what this guy should be doing, maybe even what weights should be using along with progression. You put it on white paper, looks great, but then – you need to write a training SHEET. Put exercises names, pictures, descriptions, reps, sets, weights. And then you end up spending 90% of the time for designing the damn SHEET.

There should be an easier solution. One should have a system that helps him do this. Maybe a list of Excel templates in different folders. Maybe a pro software solution.

WELLNESS

I have been trying to minimize paperwork when it comes to wellness questionnaire. Thanks to Jose Fernandez who pointed me toward iFormBuilder and KlipFolio software I have actually managed to do so using trial account period. I have been spending my free time on learning those systems and torturing user support with bunch of emails (which is EXCELLENT in both companies and I am more than thankful for all their help and patience) and have finally created a simple solution for collecting data from players using smartphones (or web log in for unfortunate [or even fortunate?] few who don’t own them). This might be sRPE (rating of session) or wellness questionnaires. No paper, no copy-paste, no formulas in Excel, no errors, no losing time. You can send notification to players, they fill it in less than 20sec and you get graphical scores in a nice dashboard.

We are still deciding whether we plan using iFormBuilder/KlipFolio combo or going for a pro solution like Kinetic Athlete. Anyway, if someone is interested in building a solution like this I am more than interested in providing consultations. It is perfect for low budget clubs.

Anyway, it is worth noting that monitoring is not a magic bullet that will make all programs work – it is a tool in you tool box. Dr. David Martin explained it the best.

INTEGRATING

What amazes me is the lack of integration of data. Staff in different clubs collect their own data in their own sheets. Some of them are lucky if they actually use DropBox or Trello or shared Google Calendar. Some use high-end solutions like Smartabase or The Sports Office. Most of them use none. Not even a white board. And most of them suffer from same organizational problems – lack of communication, lack of clearly defined roles and responsibilities and accountability. Sad but true.

I believe investing in a software like this, along with educating stuff and being on a same page is of utmost importance. Yet a lot of clubs spend zero time on this aspect. They assume this, but eventually it hit them back real badly.

WORKOUT DESIGN

I was amazed by the amount of work done by Joe Kenn to design and enlist all workout templates in my favorite strength book – The Coaches’ Strength Training Playbook. It is one of the best resources out there and luckily Joe is working on the second edition which I can’t wait.

Going back to the example I gave above – when you design a template for someone. Would’t be easy to already have a given template, select exercises from the list, select weekly progressions instead of building things from the scratch every time? Of course it would.
I am playing with AccelerWare software at the moment. It is made for strength and conditioning coaches for the designing the workouts, and running the whole business. It is VERY complex piece of software with a lot of functions and possibilities. I am just learning how to use it and will eventually decide whether to switch from Excel to it. I have been on Skype with Stewart Briggs, a coach behind it, who was kind enough to give me a run through. I am still amazed by its possibilities. I am thinking about customizing it using ideas from my Excel tables and start using it without losing time on Excel or learning and building my own solution in Access.

Now I can have all workout templates on one spot, testing batteries, set/rep/% combos and progressions and can quickly design workouts without losing time.

Anyway, I would be more than interested in hearing what other coaches are using to solve these issues. What software are you using and how are you integrating data, data basing it and implementing it to day-to-day workouts.

Thursday, April 4, 2013

Velocity-based strength training: Short Q&A with Mario Marques

Since we got Gym Aware Power Tool system last year for the purpose of tracking power output in countermovement squat jump to estimate neuromuscular fatigue (see great summary by Kristie-Lee Taylor) I have been fascinated by with the simplicity and power of its use.

I started measuring velocity and power with most of the lifts and with recent acquire of Gym Aware Pro Online it made it a lot quicker, reliable and easier.

Researching behind LPT reliability, validity and its use I came across couple of research papers regarding assessment of 1RM by using load-velocity relationship of a given movement (e.g. squats, bench press). Reading those motivated me to do my own small research which you can read HERE.

Eventually I started using the similar approach with my squad (Hammarby IF) to get some insights where is their squat strength going without testing 1RM directly or tiring them with reps-to-failure method (at least for legs – we do reps-till-technical­-failure in bench and pull-ups with and without external weight). I think this approach (i.e. load-velocity relationship) provides numerous advantages and it could be used in daily training for monitoring adaptation (tracking what is happening with your estimated 1RM over training block without actually testing it) or programming of the workouts. The velocity of movement will impact the training stimulus and subsequent the adaptations to training. It has been suggested, therefore, that athletes should try to perform exercises “explosively” at a velocity allowed by the resistance used in a volitional manner. Training at a specific velocity improves the application of force and maximum rate of force development mainly at that velocity, so that less effective training effect will occur if training velocity deviates from the specific trained velocity

Reading more about it I came across one group of authors that provided tremendous quality and practical insights when it comes to velocity-based strength training.

 IZQUIERDO M, HAKKINEN K, GONZALEZ-BADILLO JJ, IBAÑEZ J, GOROSTIAGA E. (2002). Effects of long-term training specificity on maximal strength and power of the upper and lower extremity muscles in athletes from different sports events. European Journal of Applied Physiology 87: 264-271. IZQUIERDO M, GONZALEZ-BADILLO JJ, HÄKKINEN K, IBAÑEZ J, KRAEMER WJ, ALTADILL A, ESLAVA J, GOROSTIAGA EM. (2006). Effect of loading on unintentional lifting velocity declines during single sets of repetitions to failure during upper and lower extremity muscle actions. International Journal of Sports Medicine. Int J Sports Med ; 27: 718–724 JUAN J. GONZÁLEZ-BADILLO, MÁRIO C. MARQUES, LUIS SÁNCHEZ-MEDINA. The Importance of Movement Velocity as a Measure to Control Resistance Training Intensity. Journal of Human Kinetics Special Issue 2011, 15-19 SANCHEZ-MEDINA, L., AND J. J. GONZALEZ-BADILLO. Velocity Loss as an Indicator of Neuromuscular Fatigue during Resistance Training. Med. Sci. Sports Exerc., Vol. 43, No. 9, pp. 1725–1734, 2011 J. J. GONZÁLEZ-BADILLO , L. SÁNCHEZ-MEDINA. Movement Velocity as a Measure of Loading Intensity in Resistance Training. Int J Sports Med 2010; 31: 347 – 352 L. SANCHEZ-MEDINA, C. E. PEREZ , J. J. GONZALEZ-BADILLO. Importance of the Propulsive Phase in Strength Assessment. Int J Sports Med 2010; 31: 123 – 129

So I decided to contact one of the authors and pick his brain regarding this method of strength training.

Mladen: Mario, thank you very much for taking the time to do this interview. Can you please share some info regarding yourself and your research group? How did you come to the idea to study movement velocity in strength training?

Mario: The ability of the neuromuscular system to produce maximal power output appears to be critical in many sports such as sprinting, jumping or throwing, sports that require optimal combinations of muscle strength and speed to maximize athletic performance. In the classical concentric force-velocity curve the amount of muscle tension increases with decrease in velocity, reaching the maximal tension in the isometric (i.e. 0 velocity) condition.

Under these circumstances maximal power output has been defined to occur at a shortening velocity of approximately 0.3 of the maximal shortening velocity, at a force level of 30% of maximal isometric force and/or between loads of 30%–45% of the one repetition maximum (1RM) (Kaneko et al. 1983; Izquierdo et al 2002 and 2006).

Previous studies have examined the relationship between maximal power output and load in isolated bundles of muscle fibers (Hill 1938) or in explosive movements involving upper or lower body muscle groups such as vertical jumping (Bosco and Komi 1980) or bench-press throws (Newton et al. 1997). However, there is a paucity of data on maximal strength and power of upper and lower extremities muscles in sports activities requiring different levels of strength and power, such as handball, road cycling, middle distance running and Olympic weightlifting. It is likely that the load-velocity and load-power relationships may vary between the different muscle groups, for example, in relation to fibre type distribution, different usage in sport-specific activities and/or biomechanical characteristics of the open and close upper/lower kinetic chains.

Classically, strength training programs have been prescribed according to a percentage of the individual maximal strength (i.e. 1RM). However, velocity-specific increases have been shown with strength training programs using different speeds of movement (Behm and Sale 1993). Therefore, it would be of interest to determine force/velocity and power/velocity relationships so that athletes perform training exercises at specific load and/or velocity that would be more similar to the conditions of muscle performance required in the actual competitive movement (Izquierdo et al. 2002).

Coaches and researchers in the field of resistance training attempt to identify the proper handling of training variables to determine the training stimulus that maximizes performance enhancement. One variable that is less considered when designing programs to optimize athletic performance is movement velocity. Classically, the choice of the load should impact the velocity of the movement but most of the data examining this phenomenon have been obtained with isokinetic exercise. The velocity of movement will impact the training stimulus and subsequent the adaptations to training. It has been suggested, therefore, that athletes should try to perform exercises “explosively” at a velocity allowed by the resistance used in a volitional manner. Training at a specific velocity improves the application of force and maximum rate of force development mainly at that velocity, so that less effective training effect will occur if training velocity deviates from the specific trained velocity.

In 2006 one of my Colleagues (Dr. Mikel Izquierdo from the Public Unviersity of Navarra, Spain) reported that for a given muscle action (bench press or parallel squat), the pattern of decline in the relative average velocity achieved during each repetition (expressed as a percentage of the initial value) and the relative number of repetitions performed (expressed as a percentage of the total number of repetitions performed) was the same  with all percentages of 1RM tested. However, relative average velocity decreased at a greater rate in bench press than in parallel squat performance. Conceptually, this would indicate that for loads ranging from 60% to 75% of 1RM, one may predict the pattern of velocity decrease for a given exercise, so that a minimum repetition threshold to ensure maximal speed performance would be determined (Izquierdo et al 2006).

It was showed that the velocity that elicited the maximal power in the lower extremities was lower (» 0.75 m·s-1) than that occurring in the upper extremities (» 1 m·s-1). It is not known why the velocity and the percentage of 1RM that elicits maximal power are different between the upper and lower extremity actions. Such findings are not uncommon since similar results have also been reported during traditional lifts (e.g. bench-press or squat) in young (Cronin et al. 2000; Rahmani et al. 2001; Bosco et al. 1995), middle-aged and older men (Izquierdo et al. 1999).

A possible explanation for these differences observed between the upper and lower extremities may be associated with the extremity-related differences in maximal strength, type of training, muscle cross-section area, fibre-type distribution (Lexell et al. 1983), muscle mechanics (i.e. length and muscle pennation angle) as well as functional differences according to the joint position and geometry of the joints and levers (Gu¨ lch 1994). This type of information on different muscle groups and various actions may also be useful to create optimal strength and/or power training programs for sports with different levels of strength and power demands.

Mladen: What are the differences in load-velocity profiles between upper-lower movements (e.g. squats vs. bench press) or explosive movements like clean, snatch, jump squats or bench throws? What would be their 1RM velocities on average and how do velocities at certain %1RM relate to it (velocity at 1RM)? How does the inclusion or removal of stretch-shortening cycle affect the load-velocity profile (e.g. pause squat or bounce squats)?

Mario: Yes. My Colleague, Professor Mikel Izquierdo From the Public University of Navarra (Spain) showed that, for a given muscle action (bench press or parallel squat), the pattern of decline in the relative average velocity achieved during each repetition (expressed as a percentage of the initial value) and the relative number of repetitions performed (expressed as a percentage of the total number of repetitions performed) was the same  with all percentages of 1RM tested. However, relative average velocity decreased at a greater rate in bench press than in parallel squat performance. Conceptually, this would indicate that for loads ranging from 60% to 75% of 1RM, one may predict the pattern of velocity decrease for a given exercise, so that a minimum repetition threshold to ensure maximal speed performance would be determined A different pattern of velocity declines in relative average velocity was observed when performing repetitions at different intensities between upper and lower extremity muscle actions. For all intensities tested, the average repetition velocity decreased at a greater rate in bench press than in parallel squat performance, so that in bench press performance the significant declines observed in the average repetition velocity (expressed as a percentage of the average velocity achieved during the initial repetition) occurred when the number of repetitions was over 34% of the total number of repetitions performed, whereas in parallel squat it was over 48%. In addition, it was interesting to observe that the velocity attained during the last repetition performed during the sets at 75%, 70%, 65% and 60% of 1RM was significantly higher in half squat than in bench press performance (Izquierdo et al 2006)

Mladen: You showed that velocity loss during a set is related to neuromuscular fatigue of the workout. Are there any published or unpublished data on the relationship of velocity loss during a set with adaptation seen over a training block? I know of one study that did just that. What are your opinions on the GREAT results of velocity based group? What are your thoughts on training to failure?

Mario: Yes. As I mentioned above recent studies from Izquierdo and colleagues showed neuromuscular fatigue related to repetitions to failure. (# IZQUIERDO M, IBAÑEZ J, GONZALEZ-BADIILLO JJ, HÄKKINEN K, RATAMESS NA, KRAEMER WJ, FRENCH DN, ESLAVA J, ALTADILL A, ASIAIN X, GOROSTIAGA EM. (2006). Differential effects of strength training leading to failure versus not to failure on hormonal responses, strength and muscle power gains. Journal of Applied Physiology. May;100(5):1647-56.)  It was showed that after the 11-wk training period (from T0 to T2), 1) similar gains in bench press 1RM, parallel squat 1RM, muscle power output of the arm and leg extensor muscles, and maximal number of repetitions performed during parallel squat were observed between Repetition to failure (RF) vs. NON repetition to failure approach (NRF) and NRF; and 2) the RF group experienced larger gains in the maximal number of repetitions performed during the bench press. During the peaking phase (from T2 to T3), 3) larger gains in muscle power output of the lower extremity were observed after the NRF training approach, and 4) larger gains were found in the maximal number of repetitions performed during the bench press after RF training approach (Izquierdo et al. J Appl Physiol 2006)

Sunday, March 31, 2013

Does Speed Work work? My response to Mike Tuchscherer’s article. Part 2

Does Speed Work work? My response to Mike Tuchscherer’s article
Part 2

Click here for the part 1 of this article.

INTENSITY, LOAD, EFFORT, EXERTION…

One thing I forgot to emphasize and explain in Load-Velocity profile (from now on L-V profile or L-V trade-off) was that all reps are done at MAXIMUM INTENT to lift as fast as possible (within technical limit). In another words EFFORT of each rep, at each LOAD was MAXIMAL.  In some strength circuits this is called C.A.T (Compensatory Acceleration Training).

I have created a graph to explain that submax weights could be done with less than maximum effort.

 Load-Velocity profile done with different effort levels

Using the above example I could lift 120kg at 0.55 m/s with maximal effort. With submax effort I will lift it slower (I have used percentage of the maximal velocity for a given load as percent of maximal effort, although this relationship might not be linear like this). Also, it might not be possible to slow down certain loads too much (especially not 1RM) due sticking points and TUT (endurance).

We use the word intensity to refer to a given percentage of 1RM. Recent paper by James Steele (thanks to Bret Contreras for pointing it out) argues against it and you can quickly see why in the above graph. I can lift submax load with maximal or submaximal effort. Steele recommends using intensity of load, intensity of effort to make things clearer:

 In RT, we could talk of the intensity OF load as being the percentage of 1 RM or maximum voluntary contraction that is being used. Or we might talk of the intensity OF effort involved during an exercise with the caveat that we can only gain subjective measurement of the sense of effort through RPE, and measurement of motor unit (MU) recruitment in RT provides a physiological variable correlating with effort, with max MU recruitment representing max effort independent of load --- Steele J. Br J Sports Med Published Online First

Up to this point we have talked about only single rep velocity at certain load. Using less than maximal load one could perform couple of reps until exhaustion (technical or complete failure). On the following picture is the table by Dan Baker for experienced trainers.

 Repetition maximum continuum
This is another fundamental concept in strength training and it is called repetition maximum continuum or Load-Reps trade-off.

Please note that there is no special reference to the effort of those reps (or speed) so they are usually done at self-selected pace. Also, there is an important difference in L-R relationship between exercises, level of lifters, etc. One could use Reps-till-fatigue to estimate 1RMs, although as said there is a big difference between exercises, lifters, etc thus most coaches use different tables.

In R-L continuum we are again talking about MAXIMUM reps done at certain load (%1RM). Using submax effort one could perform lower number of reps.  If we say that lifting for maximum reps athlete reaches maximum exertion (or exhaustion), then lifting for submax number of reps one reaches submax exertion.

This is one of the main principles of Mike Tuchscherer’s Reactive Training System. Mike uses RPE scale (Rate of perceived exertion) to quantify exertion for number of reps performed. You can read more about it HERE.

Another table is relative intensity which I’ve picked up from Donnell Boucher (click HERE). I am presenting here one example of such a table:

 Relative intensity table

What is common to both of these tables is the concept of quantifying how hard a given set was (in terms of exertion at the end of it). This is useful for programming since all-out-sets demands a lot from the body and demands more time for recovery.

I will visualize it by using Dan Baker table

 Performing submax number of reps at certain %1RM

Please note that this is not universal percent table – it is only an example that you can use. For more info please refer to work by Mike Tuchscherer. I have provided outline of his system HERE and HERE.

As you can see there are two inter-related fundamental concepts L-V and L-R. It is crucial to understand them, but it is also crucial to understand the terminology issues. Thus we have

Intensity of load (%1RM)

Intensity of effort (lifting speed, intent to lift fast – concentric only or concentric-eccentric; tempo)

Intensity of exertion (expressed sometimes as 5[10] which means 5 reps of possible 10 reps; one could use RPE system as well or relative intensity table)

As you can see this is all related to one set. Then we have more programing variables relating to volume aspects, like number of sets, total number of reps, tonnage, rest between sets, etc.

The authors and coaches often confuse effort and exhaustion (I have wrote about it HERE). The example that James Steel gave depict the situation perfectly:

 Along this vein of thought, however, we might also consider the differentiation between sense of effort and the physical sensations associated with exercise, which, considering the above definition of intensity, would also be inappropriately labelled as such. Indeed, these phenomena have also been recently called upon to be differentiated appropriately within the articles published in BJSM.16 17 Smirmaul16 offers a practical example appropriate to RT in this regard suggesting, “A short maximal voluntary contraction for leg extension, for example, will induce a maximal sense of effort while, initially, other unpleasant sensations will probably be modest. Repeating this maximal contraction several times, however, will increase these unpleasant sensations continuously, whereas sense of effort will always be the same (ie, maximal).” Indeed, I and my colleagues have questioned the use of RPE in RT to determine relative effort.6 Shimano et al9 showed that, when repetitions were continued to MMF, RPE was similar at 60%, 80% and 90% of 1 RM for most exercises;
* MMFMomentary Muscular Failure

Why is all of this important? It is important to differentiate between different methods and understand that a lot of authors forget to describe all related parameters, so we end up not knowing what the exact training was.

MOTOR UNIT RECRUITMENT AND SIZE PRINCIPLE

One analogy I like to make is the example of DC motor with attached battery.

 Battery = Nervous System, motor = Musculo-skeletal system; Both = motor system

In this simple example motor is the muscle and battery in nervous system. For a same level of voltage motor will behave differently (in terms of angle velocity, torque, power) based on the load at his axis (inertial, friction, air, etc).

This is pretty much along the lines with Load-Velocity profile – velocity of the motor will depend on the external load, but also on the voltage (and in this case voltage is effort).

 Effort = voltage

Thus lifting with maximal effort is like lifting with maximal voltage not matter what load is on the bar.

Another example might be lifting submax weights to exhaustion/failure (RE method). Suppose that the motor can fatigue and decrease his force/velocity output for the same voltage over time.  You attach certain load to the motor which is 50% of his maximal torque and use 50% of voltage. He is going to rotate slowly but as the motor get “tired” one needs to increase voltage to maintain rotation at certain velocity. After you eventually reach the highest voltage and are unable to increase more, the motor will stop.

This is along the lines of lifting submax weight until failure. At the end it will result with you recruiting you maximal voltage.

To make things more confusing sometimes the battery might get tired or reduce its voltage based on some feedback from the motor (e.g. temperature) to avoid complete motor breakdown (for this one needs more complex circuitry). Now we are talking about central fatigue as opposed to peripheral fatigue (at the level of the motor). Usually they are both involved in larger or smaller degree depending on what time frame we are talking about (single set, workout, week, etc), exercise, intensity, etc. You can read more about it in Cesey Butt article HERE.

Why am I saying all of this? Because according to Ralph Carpinelli it is not only the intensity of the load (%1RM) that determines motor recruitment (i.e. battery voltage):

 …That is, the size principle does not support the popular resistance training recommendation to use a maximal or near maximal resistance. The size principle and interpolated twitch studies support the contention that if maximal motor unit activation is desired, a maximal or near maximal effort at the end of a set of repetitions— regardless of the amount of external resistance—will elicit maximal motor unit activity. Effective resistance training does not require the use of a maximal or near maximal force to stimulate the available motor units and produce significant increases in muscular strength. … Despite the plethora of opinions in the resistance training literature, the specific mechanisms of fatigue and exactly what constitutes an optimal stimulus for strength gains are unknown. If a maximal— or near maximal—effort is applied at the end of a set of repetitions, the evidence strongly suggests that the different external forces produced with different amounts of resistance elicit similar outcomes …Despite the plethora of opinions in the resistance training literature, the specific mechanisms of fatigue and exactly what constitutes an optimal stimulus for strength gains are unknown. If a maximal— or near maximal—effort is applied at the end of a set of repetitions, the evidence strongly suggests that the different external forces produced with different amounts of resistance elicit similar outcomes

So the things are not so simple. I am not sure I completely agree with Ralph Carpinelli regarding the training recommendations (read the whole article), but at least this shed up some light on the issue that it is not only intensity of load (%1RM) that is important in increasing strength and maximizing muscle recruitment. Lifting submax weights to exhaustion will result in maximal recruitment as well.

I tend to believe that this is dynamic animal – there is certainly a dynamic threshold in intensity of load (%1RM) that a given trainee have to use and this might change over time. Also, there might be fatigue limit to performing submaximal weights to exhaustion and this might limit total work overall and thus limit strength gains.

I don’t want to turn this into discussion on lifting to failure or not or single set vs. multiple set, since I believe both are tools in your toolbox and needs to be done at certain periods for maximum results. What is important to get from this is that for maximal motor unit recruitment (according to Carpinelli) it might not be necessary to use maximal loads or near maximal loads.

And in the end this is the static picture I alluded to in the first part. We know that the goal is to increase 1RM, to increase battery voltage, to increase velocity around circa maximal weights, to improve technique (efficiency). But we don’t know what is the best method to come there. We know the destination, but we are not sure what the best journey is.

Will maximum recruitment yield most improvements in 1RM over time or is it something else? Force output? Number of grinding reps? Volume of lifts over 80%, over 90%? Total number of reps? At the end of the day we still don’t know.  That’s why we have programs that yield same or very similar outcomes by using totally different approaches – one might use low frequency of grinding reps (maximal recruitment, maximal exertion) usually known as HIT; one might use high volume and frequency of lower intensity of load (%1RM) like Sheiko. One  might combine different methods like Westside guys do to reach maximum recruitment in most things they do (ME for maximum recruitment with highest intensity of load; DE for maximum effort with lower intensity of loads for maybe maximum recruitment but with lower load; RE for maximum recruitment as the fibers get tired). Key message is that even if we know the static picture we still don’t know what change that static picture over time. And there are a lot of ways to skin a cat.

TALKING ABOUT THE JOURNEY

What Mike Tuchscherer believes [as far as I can tell from his writings] that will bring these improvements is the following – (1) force output during an exercises is very important stimulus and since force output changes with increasing loads [I will cover this soon] then higher loads are more important than lower, and (2) higher volume of work with this higher force output and (3) technique similarity. This is his rationale behind ditching lower intensity (50-70%) Dynamic Effort methods and putting more focus into higher intensity of load (sets @8RPE).

Basically, even if there is maximal muscle recruitment during Dynamic Effort method or Repetition Effort the force output is lower than with higher loads (%1RM) and hence will bring less improvements over time.

I am not sure how correct this is, but  I wanted to explore my Force output during different loads. I am going to use my bench press (with pause) as an example. Here is my force output during set with 60kg:

 Gym Aware output with 60kg bench press

Please note that the force is estimated using reverse dynamics using position change of the barbell. Refer to this paper for more info.

To understand the forces involved I will create a simple mechanical model.

 Simple mechanical model...
What you can see on the above graph is estimated Muscular Force. When the muscular force is over gravity force (in this case 60kg x 9,81 = 588N) then barbell will start accelerating. If the muscular force is below gravity force the barbell will start decelerating, as you can see happening during the last 1/3 of the concentric phase. If the muscular force is below zero, that means I am actually pulling the barbell down (rowing) and as you can see that happens during the last period of the lift. This happens during the lighter weights (in terms of %1RM) and I believe in greater amount during the bench press than squat (your feet are not bolted to the ground so you can pull down actually).

Here is the table from Sanchez-Medina et al. Importance of the Propulsive Phase in Strength Assessment. Int J Sports Med 2010; 31: 123 – 129 where they showed relative contribution of the breaking phase in the bench press.
 Breaking phase over  20-100 %1RM

According to this table - only loads over 80% 1RM produce no breaking phase. This is one of the reasons for using chains and bands when doing Dynamic Effort method – to extend the propulsive phase and create more force.

Here is my force output with 100kg.

 Gym Aware output with 100kg bench press

This time I need to overcome 100kg x 9,81 = 981N to get the bar moving. And there is not below zero force (no pulling the bar).

On the next table I have compared Peak Force output during concentric phase against different loads when reps are done with maximum effort (C.A.T.).

 Peak force output over %1RM continuum in bench press

Peak force is the highest force achieved during the concentric phase. Using mean force output will yield weight of the barbell – so I have used peak force.

As you can see there is a curvilinear relationship (I have used polynomial equation on the graph and linear on the table, as you can see R2 is higher on graph). Bret Contreras posted similar picture from a study by Swinton et al. that is pretty much in line with this one.

According to my bench press data, to reach over 90% of Peak Force output one needs to use loads over 82% 1RM. To reach over 80% of Peak Force output one need to use more than 68% 1RM.

To make sure that this is also the case with squat I compared my squat numbers with even jump squat.

 Gym Aware output during squat jump with 20kg
When I put everything in table this is what I get

 Peak force output over %1RM continuum in squat

According to this sample, loads needed to reach over 90% of Peak Force are over 84% 1RM and to reach over 80% of Peak Force one need to use over 73% 1RM.  Here is the table

 % Peak Force Bench Squat >90% >82% 1RM >84% 1RM >80% >68% 1RM >73% 1RM

It seems that Mike Tuchscherer is right in this regard – One cannot reach peak barbell force outputs with submaximal loads even if he utilizes compensatory acceleration.

[Disclaimer: The forces explained here are the forces acting on the barbell and not Ground Reaction Forces. To estimate those I have added 100% of my BW to the load . This is what I got:
 Estimated GRF forces using 100% BW along with barbell weight

As you can see, using 100% BW into calculation I managed to produce the same peak force during the 20kg countermovement jump and 160kg squat. Does this mean I need to work more on my strength levels since I’ve utilized full its potential in the jump? I have no clue – I would need more data and need to think more about this since I just discovered it for the purpose of this article. Having a force plate might help as well.

This is also an example of result dependency on measurement method as I have alluded in this post on power measurement. Anyway, according to this study barbell kinematics should not be used to estimate barbell and body system center of mass in the back squat. So using barbell velocity as a representative overestimated barbell-body center of mass velocity and hence acceleration, power and force.

Anyway, if I stick to squat performance (without jump squat) to reach over 90% of peak GRF one need to use more than 74% 1RM and to reach over 80% of peak GRF one need to use more than 54% 1RM – a lot less than when we consider only barbell force. The question now is which one is more important – GRF or barbell force?

End of Disclaimer]

I believe that you are confused at this moment. Welcome to the club. To summarize – Mike Tuchscherer is right when he says that one can’t achieve peak forces with loads less than 80% 1RM when one take forces applied to the barbell only. In the case with peak GRF (in squat; estimated using LPT, but I would need force plate to be more certain) one needs loads higher than 70%.  Please note that Dynamic Effort uses 50-60% 1RM raw loads.

One thing to consider is that my C.A.T. with submax loads is NOT the same as Dynamic Effort. In Dynamic Effort one is performing both eccentric and concentric parts explosively for 2-3 reps, plus add chains or bands to the equation and the forces might be much higher than with my pause technique. But you also have sitting on the box that might actually decrease it. Without measuring it I can only speculate.

So even if Mike is right when it comes to force outputs, does it means that force outputs are key stimuli for strength improvement, or something else? Only the experimental study could tell us this. And not done on college kids or weak coaches (point taken), but on real powerlifters. Changes should be estimated using smallest worthwhile changes. Anyone up for an experiment give me a call.

CONCLUSION

Conclusion is that the things are complex and there are a lot of ways to skin a cat. I cannot say with any confidence that DE works or not. Plus, one needs to take into account the whole training system and not only one method the system uses It is only tip of the iceberg. This brings me to my opinions that you should take with grain of salt.

I do think that Dynamic Effort is a little bit overrated. I am leaning more toward Mike Tuchscherer’s side, but I am maintaining my skeptical attitude. Mike is probably right when he says that force outputs are lower in DE then when working with higher loads (not necessary to exhaustion; in his system around 8RPE), along with different technique of execution which might not bring transfer. But again, are these the sole things behind strength increase stimuli? We don’t know.

One thing to consider is that DE might work for the other reasons instead of developing explosive force for blasting through the sticking point (this might be an interesting study to find out). When one works with ME twice a week and really pushing it, then he is not left with much than to do easier weights (50-60%) the next two day. This is similar to the polarization of the training for endurance runners.

This is why it is important to take a look at the big picture. Numerous champs are using this Westside, but numerous tall humans are playing basketball which doesn’t prove basketball make humans tall. One could use different methods during different phases.

This study (although sketchy) showed higher improvements in bench press in group performing it with C.A.T and before velocity drops below 80% of the  best rep, even when doing less volume compared to a group who did self-selected lifting speed to failure. I am very interested in this velocity based strength training at the moment – and I believe there is a huge potential in this approach.

One idea might be to utilize accumulation phase(s) using higher number of sets, lower number of reps with relatively higher %1RM (75-80%) with NO grinding at all and with C.A.T. (that is around 8RPE according to Mike) before switching to more Westside program for couple of weeks/months, where DE might be utilized as a complement to ME session.

I hope you have enjoyed this article without any confident conclusion.

Friday, March 29, 2013

Does Speed Work work? My response to Mike Tuchscherer’s article. Part 1

Does Speed Work work? My response to Mike Tuchscherer’s article.
Part 1

INTRODUCTION

Mike Tuchscherer’s article Why Speed Work Doesn’t Work lifted a lot of dust lately. I have read Bret Contreras’, JL Holdsworth’s and Chad Smith’s responses and I have wrote some of mine ‘comment’ on Jim Wendler’s Facebook Wall

Today Mike contacted me and invited me to expand further and continue the discussion on his forum since he found my comment interesting. Thus I decided to write one blog entry as a starting point, along with explaining my rationale/viewpoint.

I have huge respect towards Mike, what he is doing, both as a lifter and as a coach. I have learned a ton from him and he was really helpful with his responses to my emails and questions.

Before I type anything I need to make couple of things straight. First of all I am not powerlifter nor I coach powerlifters. I do not coach strength athletes either, nor bodybuilders. I work with team sports athletes that demand a mixture of physical qualities ranging from power, speed, endurance, strength, but most importantly technical and tactical skill. I have some data on my own lifts by using Gym Aware LPT system which I will present shortly, but since I am weak as kitten (compared to elite powerlifters) take them with grain of salt (in more scientific term it is hard to make any inferences to elite powerlifting population from my own lifting samples). I will mainly reference some studies and use rational thought (that needs to be confirmed with scientific/empirical method).

LOAD-VELOCITY PROFILE

Load-velocity profile [trade-off] is one of the most fundamental concepts in kinesiology, emerging in characteristics of single muscle fibers, single joints and finally of multi-joint complex movements. I am not sure we completely understand why it happens and what is the exact mechanism - even at the level of basic muscle fiber – and not even at the level of complex movements governed by even more complex nervous system.

Anyway, load-velocity trade-off is there even if we don’t understand it completely. To make things simpler I will refer to common strength training movements like bench press and squat when I discuss load-velocity trade-off. I have written couple of articles regarding velocity-based strength training and using load-velocity profile of the lifter for estimating his 1RM and prescribing training HERE (make sure to follow links in the text).

One can look at load-velocity profile as a formula, where velocity of a movement [V] is predetermined by external load [L].

V (L) = a x L + b

Constants a represent slope and constant b represent the intercept.  In short: velocity of a movement depends on the external load.  Here is my load-velocity profile for the squat (pause around 1sec at the hole).

 Load-Velocity profile for squat

As you can see correlation is nearly perfect between the two. I took 160kg as my 1RM and associated speed was 0.3 m/s (mean concentric velocity). If I use regression formula (one could use =TREND function in Excel, or manually by using slope and intercept), velocity at 160kg is estimate to 0.301 which is practically exact (as can be seen by low SEE). Thus one could use this regression to estimate 1RM.

Note that 1RM doesn’t always happen at 0.3 m/s. My bench press is somewhere around 0.15 m/s and this might depend on the level of the lifter (beginner, intermediate, advance), movement (small vs. large muscle mass involved), type of lifter (ST or FT, grinder or explosive), etc. So it is individual.

GOAL OF POWERLIFTING

What is the goal of powerlifting? The goal is to lift as much weight as possible without time reference. So one could lift 200kg in 4 sec and another might grind it for 20sec. Same results – so the movement velocity of 1RM doesn’t matter in powerlifting.

Looking at the curve above the goal is to move 1RM to the right (i.e. from 160kg to 180kg). What happens with the slope of the curve doesn’t really matter – powerlifters are not competing who can generate more velocity with submax weights. This can’t be said for other sports!

Sometimes even if the 1RM doesn’t improve, if the velocity (and thus power output) at certain submax load (usually representing external resistance common to sport competitions [and NOT working around some magical load that produces peak power output]) improves that represent positive improvement. This is of no importance in powerlifting though.

Here is the possible scenario of me improving velocity without improving my 1RM which is still important in more [real] power dominant sports.

 Improvements in Velocity at without improvement in 1RM
And here is the possible opposite scenario of me improving my 1RM without much improvement velocities at submax load.

 Improvements in 1RM without improvements in low resistance velocities

Third possible solution might be shifting the whole graph to the right by improving both 1RM and submax velocities.

 Improvements in both submax load velocities and 1RM

From a powerlifting standpoint the only important thing is improving your 1RM. Speaking of this I can improve my powerlifting result by not even affecting the load-velocity curve. You wonder how? By simply learning to grind more weight and in becoming more confident in it. Check the graph – I am learning to grind and I am able to lift 180 kg at lower speed.

 Improving grinding?

I am not sure if this is an improvement (development) or rather learning to express what one already have – and this goes pretty much in line with my develop~express concept. More experienced powerlifters and/or scientist might chine in on this topic. Also – can you change your grinding speed? Please chime in in the comments or on Mike’s forum

Going back to situation where the load-velocity curve improved so that 1RM improved, while velocity at submax weight didn’t (I am re-posting it again)

As you can see from the graph, as I have improved my 1RM I have also improved lifting velocities in the zone around 1RM. I am not sure if this is circular causation so the opposite is also true (i.e. improving velocities in the circa-maximal zone will improve 1RM). And I believe this is the CORE ISSUE here so I will bold it:

 If improving 1RM also improves submax velocities, will improving submax velocities also improve 1RM? And who is first – chicken or the egg and what is the best way to improve each?

Since this is the chicken or the egg problem (as long as I don’t see experimental study with groups) automatically assuming process by the outcomes might be misleading. What do I mean by this? We have a tendency to believe/assume that using loads/velocities associated with one part of the curve will improve that same part of the curve. We can see this same rational flaw in distance running – and I HIGHLY suggest checking this great article by Steve Magness on Physiologial Model of Training (Note to Steve: if you are reading this I am still awaiting for the part two) and Attacking Adaptation from Multiple Directions.

In plain English – will using circa maximal loads (90+%) improve 1RM better than submax weights over time? Will peak power be mostly improved by utilizing loads associated with it? Will VO2max be mostly improved by using VO2max workouts? Will lactate threshold be mostly improved by utilizing lactate threshold workouts? Is the best way to improve soccer skill by playing 10v10 all the time? And many more examples of develop~express confusion, misunderstanding of the specificity principle and training transfer along with highly mechanical/linear thinking.

I have written about this during 2009 in my Planning the Strength Training article, but I was mainly referring to the repetition continuum that you can see in most strength and conditioning textbooks:

 Repetition Continuum

 It can be said that reaching of the different strength training goals (and thus motor qualities) is based on utilization of different loading protocols (weight, reps, sets, tempo, rest, etc.) or methods. So, each of the methods aimed at reaching different strength training goal utilize different loading protocols. This is based on the repetition continuum, or the ’idea’ that different goals can be achieved utilizing different reps per set. There is a dynamic interaction between the variables of reps, sets and loads. The load used (% of 1RM) ultimately determines how many reps per set are done. Reps per set (or set time) ultimately determines how many total sets must be done. The interaction between the three will affect what adaptation is seen. Although not all authorities agree, there is thought to be a continuum of adaptations which may occur with different repetition sets. This continuum is called repetition continuum. --- From Planning the Strength Training, 2009.

We have tendency to think this way and rationalize training methods, but it might be flawed. It is same as thinking that playing basketball will make you taller because basketball players are tall. Yes this is a bit extreme, but it is same flawed reasoning.

Maybe I am nitpicking, but this might be reason of our frustration to understand same results with totally different programs and appreciate that what brought someone from A to B, might not bring him from B to C.

Here is an example in running – the HIIT is quite popular and research is showing that runners who start doing more HIIT improve their performance and aerobic capacities more (there is the difference between improving VO2max and performance, see article by Steve Magness). And yet we see that most elite runners do mainly great volume of low intensity work and the ones who improved more did that by increasing low intensity volume instead of high intensity volume (see article by Seiler).

When it comes to training we believe that the best way to improve 1RM (or strength) is to do loads very close to 1RM. And yet we have extremely strong lifters using Sheiko routines that are mostly 75-80%. It might be also interesting to read interview with Carlo Buzzichelli by Bret Contreras regarding this issue.

Enough for today – I have covered some basic theoretical/philosophical and maybe even practical aspects of this issue. I will leave you with the resources linked for now and continue soon with more practical words.

Stay tuned till part two…