Middlesex Student Conference 2019

It’s a little bit later than planned but just wanted to do a review of the 10th Annual Strength and Conditioning Student Conference, at Middlesex University London, Saturday 9th March 2019.

Thanks to Dr Anthony Turner who has done a terrific job in organising it over the last 10 years and will be handing on the job to Chris Bishop!  I’ll devote a whole blog to JB-Morin talk as I have a few more things I’d like to go through there!

Talk 1- Chris Bishop: Inter-Limb Asymmetries: Calculating Differences, Effects on Athletic Performance, and Methods to Reduce Imbalances

I wouldn’t be doing this justice with the slides I’m about to post as there was a lot of information.

Key Points:

  • Wide use of Methods for Calculating Asymmetry
  • Useful to Determine Day to Day ‘Variability’ before assigning significance to a change
  • Limb Difference Varies Across Tasks
  • Useful to note Direction of Asymmetry

It appears there is conflicting research regarding the correlation between asymmetry and athletic performance.  In one research paper showed us, a strength imbalance (asymmetry) did not make any difference to how well you performed a change of direction test.

  • In Chris’ 2017 Systematic Review he found 12 out of 18 studies may indicate a harmful correlation (negative) between asymmetry and athletic performance
  • In his 2019 Updated Review he found 19 out of 28 may indicate a harmful correlation (negative)between asymmetry and athletic performance
  • Eccentric Impulse is more stable than Jump Height
  • Strategy based metrics need to be investigated (the ‘How’) as well as the outcome of the Jump Performance (the ‘What’).

So what? Chris was astute to point out that in elite sport the bottom line is who finishes first! So he gave a hypothetical example of three sprint cyclists who have different levels of asymmetry resulting in varying power outputs between limbs.  While the rider A had the biggest asymmetry he was also able to produce the highest mean power most likely resulting in the fastest time.  So context is king and the process and the outcome have to be looked at together to determine the impact and directions for future training.

 

Talk 2: Professor Kevin Till- Who, What, How- Plan, Deliver, Review: A Framework for Decision-Making in S&C Coaching

Key Points:

  • Reflection is done better when Planning is done well!
  • The more time you spend planning the more beneficial reflection will be
  • Reflection IN ACTION – During session
  • Reflection ON ACTION – Immediately after
  • Role of Coach: Problem setter NOT Problem solver

 

Talk 3: Dr John McMahon- Optimising Force Plate Assessment of Vertical Jumping in Team Sports

This talk was arguably my favourite- not least because I’m on a personal crusade to better understand Forces in Sport and John did a terrific job of breaking down a Force-Time curve for me!

Key Points:

  • Set up (calibration) of the Force Plate is key!
  • Use simple and consistent cues and protocols
  • Drop jump (30cm box <250m/s) vs Depth jump (greater heights and would spend more time in contact with ground with increased knee flexion)
  • Be aware of Fall Height vs. Box Height (if an athlete raises centre of mass at take off rather than just stepping off could cause errors of 10% or more!)
  • Consider different types of jump profile for further assessment- such as Repeated jumps x 10 and his ‘Buy One Get One Free (BOGOF) jump which is a countermovement jump into a pogo jump)

I particularly loved the break down of the Force-Time curves for consideration of the different components we typically measure:

Notice how it is the Force that the athlete generates creates the Impulse which then causes the acceleration, which causes the velocity and so on…

 

Hope you have found this article useful.

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Daz Drake on Maximal Strength Training

I have Duncan French to thank for putting me on to a journal article in his 2018 UKSCA UFC presentation- when he was going through his needs analysis for MMA.  He actually didn’t even say much about it but as soon as I saw that slide a light bulb went off in my head and I knew when I finally got the copy of the presentation I needed to read the original journal article.

This blog is the cliff notes of the presentation Duncan gave and it sets up my rational for the importance of maximal strength.  This blog will make it more clear what maximal strength will and will not directly help in sports performance.

I like the use of the word ”underpin” when referring to high force qualities and their relationship with high-velocity techniques.  He then followed that up with this slide which featured the journal article I was talking about.  If you want to get a copy of it for yourself click the link HERE.

What does this mean?

Well let’s start by exploring what these terms mean.  Rate of Force Development (RFD) is measured as the slope of the Force-Time curve obtained during isometric contractions.  This is important to study as the time allowed to exert force in a range of sports is typically very limited (~50-250ms).  In contrast longer time is needed to exert maximum muscular force (>300ms).

Critically for this discussion, RFD in various time intervals from the onset of contraction is affected by different physiological parameters.

In the study above they examined the relationship between voluntary contractile RFD and (1) voluntary maximal muscle strength and (2) electrically evoked muscle twitch contractile properties.  Maximal muscle strength is also known as Maximal Voluntary Contraction (MVC).

The main finding from the study was that voluntary RFD became increasingly more dependent on MVC and less dependent on muscle twitch contractile properties as time from the onset of contraction increased (Figure on the right).

Put another way, contractile RFD during the very early phase of muscle contraction (<50ms) is related to the intrinsic contractile properties of the muscle, whereas RFD during later time intervals (150-250ms) is related more closely to maximum muscle strength

The graph on the left indicates that the voluntary RFD measured at the time interval of 200ms was strongly correlated with MVC, where the explained variance (r=0.89) was 89%.  This means that 89% of the variance in voluntary RFD at 200ms can be explained by the variance in MVC.

In conclusion this means Maximal Strength training has a great influence on Voluntary RFD >90ms especially around 150-250ms which we might define as Late RFD.  So for things like acceleration in sprinting, jumping and change of direction maximal strength could have a big impact on directly enhancing sports performance.  When it comes to things like the ground contact during top speed sprinting and unloaded striking and kicking, maximum strength could ”underpin” high velocity movement.  However, training would need to be more targeted to early RFD training methods to improve these qualities.

 

How do you Measure Maximum Strength?

Now we know maximum strength is important how do you measure it?  The traditional weight training method is to determine your 1 Repetition Maximum on a Back Squat or Deadlift.

You can calculate the Peak Force in Newtons once you convert your body mass into weight, and add the weight of the bar.  A elite level of strength on the back squat might be around 2 x body mass so for a 85kg male (weight of 833 Newtons plus weight on bar of 1666 Newtons) that’s a total Force of 2,499 Newtons.  This is sometimes represented as a unit of acceleration as a multiple of body weight, which in this case is 3.0 times body weight.

The back squat is limited by your concentric strength in the weakest part of the movement (the bottom of the descent).  A preferred method to determine strength is using the isometric method.  Elite levels on an Isometric Mid Thigh Pull (IMTP) are as high as 4.0 times body weight.  We know that we can create more force isometrically than we can concentrically so a goal to aim for would be to develop 3.0 body weight concentrically and 4.0 body weight isometrically.

What’s next?

Having built Maximum Strength as measured by strength in the Isometric Mid Thigh Pull (IMTP), we need to transfer that strength into sport specific attributes.  I’ll go into this in more detail in a follow up blog but this is the first time I have seen the concept of ”Dynamic Strength Deficit”

(CMJ Fpeak / IMTP Fpeak)

Using the results of the study by Kawamori_et al (2006) they recorded a Peak Force on the IMTP of 3,177 Newtons, and 1,449 Newtons on the Counter Movement Jump.  Using this example the Dynamic Strength Deficit would be (1,449 / 3177) or 0.47 indicating extra training time should be spent on dynamic strength training.

In terms of Speed-Strength monitoring to see if the dynamic strength is improving, Duncan went on to share the initial findings they have been getting from the use of the Landmine punch throw– which I believe ”Boxing Science” first came up with.

 

In the next blog I’ll look a bit more in detail at the Power Protocol used here and the Jump profile I use in Tennis.  This way you can profile you athlete in terms of Force and Velocity.  I hope you have found this blog article useful and now understand how maximal strength can help improve sports performance.

Remember:

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  • Share this post using the buttons on the top and bottom of the post. As one of this blog’s first readers, I’m not just hoping you’ll tell your friends about it. I’m counting on it.
  • Leave a comment, telling me where you’re struggling and how I can help

Since you’re here…
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