The Influence of Neck Stiffness on Head Kinematics and Maximum Principal Strain Associated With Youth American Football Collisions

A recent article from the Journal of Applied Biomechanics and on Neck injuries which is a current hot topic.


Janie Cournoyer
David Koncan
Michael D. Gilchrist
T. Blaine Hoshizaki

University of Ottawa;
University College Dublin

Published: 08 Mar 2021

The purpose of this study was to investigate the differences in head kinematics and maximum principal strain in youth American football helmet-to-helmet collisions between an unbiased neckform and prototype neck apparatus, including springs, representing the upper trapezius, the splenius capitis, and the sternocleidomastoid muscles, for 3 impact velocities, 3 impact locations, and 2 striking masses. This research was part of a larger project funded by the National Operating Committee on Sport Safety Equipment to inform youth helmet testing procedures.

Understanding the relationship between head mass and neck stiffness during direct head impacts is especially concerning in youth sports where athletes have higher proportional head mass to neck strength.

For full study results and conclusions click on the link

The Influence of Neck Stiffness on Head Kinematics and Maximum Principal Strain Associated With Youth American Football Collisions


Exposure to impacts across a competitive rugby season impairs balance and neuromuscular function in female rugby athletes

An Original research paper that went under the radar, another science paper coming out of Canada.


Stephanie E Black

Bruno Follmer

Rinaldo André Mezzarane

Gregory E P Pearcey

Yao Sun

Dr. E Paul Zehr

  1. Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, BC, Canada
  2. School of Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC, Canada
  3. Human Discovery Science, International Collaboration on Repair Discoveries (ICORD), Vancouver, BC, Canada
  4. Laboratory of Signal Processing and Motor Control, Faculty of Physical Education, University of Brasilia, Brasilia, DF, Brazil
  5. Centre for Biomedical Research, University of Victoria, Victoria, BC, Canada
  6. Division of Medical Sciences, University of Victoria, Victoria, BC, Canada

The study did an objective assessment tools to detect subtle neurological deficits that accompany repetitive and mild head impacts in contact sport across a

What are the new findings in the study:

► A competitive rugby season induces subtle deteriorations in neuromuscular function that is not captured in traditional sideline assessment.

► Differentiation between static stances which range

in difficulty is relevant to uncover subtle changes in


► Tandem-leg and double-leg static stances are sensitive to detect centre of pressure alteration following

a season of recurrent head impacts.

► Spinal cord excitability measurements suggest deviated values at baseline


The study also found impact in clinical practices in Future studies.

► Implementing an objective balance measure as a clinical assessment may uncover subtle neurological. impairments without diagnosed concussion.

► Double-leg stance is often overlooked by subjective assessments, but it provides an insightful outcome if performed using a sensitive tool.

► The challenging tandem-leg stance over a foam pad notably contributes to a clinical assessment after recurrent mild head impacts.

► Spinal cord excitability may be suitable for detecting particular neurological patterns in female athletes exposed to head impacts performed using a sensitive tool.

Study Conclusions:

The study concluded that quantitative measures revealed that exposure to impacts across a competitive rugby season impair balance in two specific stances in female rugby athletes. Tandem-leg stance on an unstable surface and double-leg stance on firm surface are useful assessment conditions when performed over a low-cost balance board, even without clinically diagnosed concussion.

Click on link for full study: Exposure to impacts across a competitive rugby season impairs balance and neuromuscular function in female rugby athletes

Single leg hop for distance symmetry masks lower limb biomechanics:

Time to discuss Single Leg Hop distance as decision criteria for return to sport after #ACL reconstruction ?

A MUST read paper and not surprised after seeing the authors associated with the work

The study evaluated the lower limb status of athletes after anterior cruciate ligament reconstruction (ACLR) during the propulsion and landing phases of a single leg hop for distance (SLHD) task after they had been cleared to return to sport.

The Authors wanted to evaluate the biomechanical components of the involved (operated) and uninvolved legs of athletes with ACLR and compare these legs with those of uninjured athletes (controls).

For the full paper click on the link : bjsports-2020-103677.full


How to Build Strength in Rock Climbers – Part 1

Most people have known me as Strength and Conditioning Coach primarily for Team Sports (Rugby Union and American Football), however, my passion has always been Rock Climbing since as long as I remember. So at present I have switched my focus to build strength in Climbers.

Even with Rock climbing in the Olympics it is still hard to get climbers in the gym to strengthen their bodies. I think it’s too easy to confuse a hard workout with effective training. In most cases that I have encountered athletes have little understanding of techniques and adding strength exercises to poor technique is simply a way of reinforcing that poor technique.

Looking at other sports can be a useful tool when it comes to knowing how to train climbers. the problem is many Athletes look at the wrong sports for comparison. Climbing is nothing like triathlon or distance running; it’s more like gymnastics. One of the most important lessons we can take from elite performers in sports like rock climbing is that there are no top-level athletes that just use their sport as conditioning for that sport. In this regard, rock climbers that don’t do supplemental strength training are about behind elite-level athletes in similar sports. This is evidenced by the fact that the best climbers of today can still perform at a world class level in multiple disciplines.

The proposed format for Olympic sport climbing will require participants to compete in all three disciplines – lead climbing, speed climbing and bouldering, this means that as part of training power and explosive movement exercises must be included.

Understanding that a maximum level of strength and power cannot be maintained even by doing the most intense climbing does not contradict the principle of specificity but highlights it. The reason strength training must be done outside the climbing wall is because climbing’s multi-faceted nature doesn’t allow for sufficient focus on strength alone. When high levels of the sport are reached, training must become “partitioned” in order for the climber to advance. The hardest moves on rock simply cannot be correctly executed without sufficient ability to generate force.

The mechanism by which supplemental strength training helps climbers should be understood. The basic idea is that for any given move, a stronger climber will use a smaller percentage of his maximum strength. Thus he’ll be better able to climb with technical correctness and will be more resistant to fatigue. Elite-level climbers rely heavily on the ATP-PC (anaerobic alactic) energy system, the energy that is present and most-readily available for muscular work.  This energy system is the system by which the body fuels 10 to 20 seconds of intense exercise by using stored ATP, the high-energy molecule that fuels muscles, and then through phosphocreatine, which is quickly converted to ATP to further fuel muscle contractions.

This system is best developed by increasing strength and power. Elite level climbers don’t rely as heavily on glycolytic (anaerobic lactic) metabolism, which allows for quicker recovery at rest stances and better day-long endurance.

How much supplemental strength training is appropriate? Depending on the time of year, Climber should do between 2 and 4 short strength sessions per week. During a preparatory or off-season period, building strength is a priority. This is also called Periodization:

This is defined as the systematic planning of athletic or physical training. The aim is to reach the best possible performance in the most important competition of the year. It involves progressive cycling of various aspects of a training program during a specific period. Conditioning programs can use periodization to break up the training program into the off-season, preseason, in season, and the postseason. Periodization divides the year-round condition program into phases of training which focus on different goals.

Many athletes train strength during the Autumn-winter only to see decreases in strength as they move into a peaking or performance phase. a plan must be in place on maintaining some level of strength and power training throughout the year.

Training that increases muscle size and strength can be useful but building maximum strength for minimum size is the most important training goal. By careful planning, this is straightforward. By avoiding hypertrophy (increase in muscle size), we create an increase in relative strength, making for a more efficient climber.

Another way of looking at it is that absolute Strength is the maximum possible force a muscle could generate. Maximal Strength is the maximum force that can be initiated in athletic movements, usually 70-90% of absolute strength. Finally, the Strength Deficit is the difference between the two. Strength training is the method of reducing this deficit.

In part two of this article, I will cover the specifics of planning and implementing strength training in a climbing program


Essentials of Strength Training and Conditioning, Fourth Edition: Greg Haff, N Travis Triplett

National Strength & Conditioning Association (U S )

The Strength and Conditioning Bible: How to Train Like an Athlete Nick Grantham

Training for the New Alpinism:  Steve House and Scott Johnston




Wednesday Rehab – Passive Stretching R2 Mobility for Grumpy Quads 8

Hahaha I love bringing some fun into the rather serious world of Rehab  – I’m hoping R2D2 might be feeling a lot looser since last session of Myofascial release ;))…. how about you?


But now to KEEP some of that looseness, we need long periods of holding on stretch near the R2 limit. Straight after myofascial release. Use that window of freedom to lock in some longer term changes.


These two passive Quad stretches should be absolutely taught to every client with knee, hip, and low back issues. They each have slightly different values, can you feel the differences?


A few key elements to enhance these intense stretches:

  • Check your knees are supported under soft padding if kneeling
  • Check your knees don’t feel pain during Quad stretching (although I do sometimes think that the pain felt can be stretching of fascia near the lateral patella..) tricky to know.
  • Use pelvis posterior tilt to further enhance the stretch. KEEP your chest up for maximum value.
  • Breathe; relax and let go of tightness,
  • Hold 30sec at a time, no less! Do 3-4 reps.

How often – Well, how much time you got? No limits, really to how much you do. You could easily do 5 sets per day you know that? Ohh the changes would happen so much faster

Check the Video:

Hopefully your Quality Quads start to loosen before R2D2’s ever will….

Sunday Videos – How to correct


How to correct Bench Press Biomechanically – Bench press optimisation (subscapularis)


Wednesday Rehab – Serratus Anterior

Sky Punching

In this series a lot more than just Serratus is being targeted … in fact your abdominals may scream more in this series designed by Mark Davis and coached by Chris Mallac. Not for the faint-hearted.

Actually “Sky Punching” are a perfect breakdown progression for the famous Turkish Get-ups – you’ll see what I mean when you watch it.
Now, enjoy the Video

Have a good week

Wednesday Rehab – Serratus with Thoracic Rotation Drills

I hope you have been adding some specific Serratus Anterior work into client exercise sessions! Add them into rest periods as a “Filler”, or do 2 min warm-ups and 2 min warm-downs of these Serratus drills.

Serratus is the powerhouse of the shoulder and links the arm to the thoracic spine (todays video shows you how to get them both working together) – especially critical for types of exercise like boxing, tennis, Vipr, cross body cable drills, and kettlebells.

Remember the Cue :

“Reach with your armpit”, or

“Keep your elbow directly behind your hand during push movements”.


Today’s video shows you a couple more cues helpful in the pushing movement and linking it to thoracic rotation (Q: do you think that internal rotation or external rotation of the Glenohumeral joint switches Serratus on?); check it out

Have a Merry Christmas and see you in the New Year

Wednesday Rehab – Poor Serratus – Poor Posture

Mostly when we talk about retraining or improving posture we talk about the role of Lower Trapezius to pull the shoulder back and down, but colleagues and I have been wondering if the role of Serratus Anterior is actually MORE important in good posture.

If your scapula is stuck forward and down due to Pec overactivity, or sits too high due to Upper Trap overactivity, then simply “ Back and Down” will NOT reposition the scapula and shoulders well – in fact it will make everything worse.
See the video for examples of trainers around the word all trying to effectively engage good scapular posture, even though they have “winging”, or “Rounded Shoulders”, or overactive Upper Traps.


Today’s challenge is for you to find the Brain Switch for Serratus Anterior in standing posture without load. Not easy… these days I am using different  cues to help people learn it, depending on what works for them:

“Pull Your Armpit up to the front of your shoulder”, or
“Bring Shoulders up, back, down and…out towards your armpit”.

The challenge is for you to find the Brain Switch for Serratus Anterior in standing posture without load. Not easy… these days I am using different  Cues to help people learn it, depending on what works for them:

“Pull Your Armpit up to the front of your shoulder”, or
“Bring Shoulders up, back, down and…out towards your armpit”.






Did you get that you are actually doing a mini Lat Spread?

Wednesday Rehab – Upper Trap Mystery – Part II

A few people writing in wanting to understand why their Upper Trap area gets so sore.. There is no doubt that it is often more complex than just stretching or doing myofascial release to those muscles, because it usually doesn’t really fix it. Just like cracking your back doesn’t usually fix back pain!

Today ‘s article tackle two very big controversies in the world of rehab and strength – they both relate to our tricky friend Upper Traps and are:

  • Should we stretch or strengthen Upper Traps for rehab??
  • Do Shrugs work even work for strengthening Upper Traps?


In the attached article, Chris Mallac and UIrick Larsen tackle this controversy and continue our exploration of the Upper Trap Mystery in Part II:

Rehab Trainer Upper trap Mystery 2

Be warned – it is quite a technical article this time as well, so you have to be fresh in your brains to understand it!

A bit of quick anatomy to try and understand more in depth the Upper Traps and where they insert:









And don’t forget the little videos from last week that really show the muscle in action – the debate centres around whether the video on the Left is accurate… Does the Upper Trap even do Shrugging??