Karim Darwish’ Backhand: Squash Biomechanical Analysis

July 22, 2009

In an earlier post we wrote about the general method for doing a biomechanical analysis of  a squash stroke by breaking the stroke down into five phases and using seven biomechanical principles to analyze it.  I also posted an example of an analysis of a squash forehand drive, and a video of a tennis forehand drive biomechanical analysis (similar but not identical ideas for analyzing a squash forehand).

Premier Performance Coaching Team 2009

Premier Performance Coaching Team 2009

I recently had the chance to video the strokes of the current world #1 Karim Darwish at the Premier Performance Squash training held July 10-19 at Mercersburg Academy in Pennsylvania.  Along with Engy Kheirallah and Miguel Rodriguez we coached 20 adults and juniors using the Games Approach framework to introduce the players to Egyptian style attacking squash.  In addition to on-court coaching we spent quite a bit of time reviewing video of both game play tactics and forehand and backhand basic strokes.

For the biomechanical video analysis, since we were using a Mac and not Dartfish on a PC, we made a Quicktime video clip of Karim’s and each campers strokes, and opened both clips at the same time side-by-side for easy comparison.  Although I used the seven biomechanical principles to anlalyze the players strokes, it was very useful to be able to refer to Karim’s technique in each of the five key positions:  ready position, backswing, force production, impact, and follow through.

Betsy & Karim's Forehand Preparation

Betsy & Karim's Forehand Preparation

In this video I walk slowly though an analysis of Karim’s basic backhand straight drive off an easy ball in the mid-court (note that you need to specify the exact shot being analyzed since technique differs depending on the situation) using the seven biomechanical principles.  The most notable aspect of his backhand stroke is the extreme “blocking” action of the left arm during the follow through, compared to most of his peers.  The purpose of the blocking action is to slow rotation of the body (as in a figure skater opening out of a spin), which will help keep his hitting zone longer and shoulders turned for a fraction of a second longer.  Most players will do this on precision shots such as the straight drop or straight volley drop, but Karim does it while hitting with power as obviously his racquet speed is sufficient – he does it much less on his cross-court drives.  Stay tuned for an analysis of his forehand stroke.

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Biomechanics for Squash Coaches

December 3, 2008

Earlier today I did a search of the world’s largest database of sport research and did not turn up a single accessible scientific article on the biomechanics of squash.  There were a few non-scientific articles in Sports Coach, an Australian coaching magazine, and some links to Conference Proceedings (i.e., someone presented on a topic at a conference so we might have access to a one-page abstract).

Furthermore, there are no published guides for squash coaches similar to Duane Knudson’s 2006 “Biomechanical Principles of Tennis Technique:  Using Science to Improve Your Strokes”.  Ideally there should be a dynamic interaction between Biomechanics research and squash coaching and playing:  a player or coach develops a new way of hitting the squash ball or moving on the court that is “verified” by a research study – or a new research study exposes a better way of executing squash technique.

biomech_

The actual paradigm that has been used in squash, and that is still in use today, is that a top player, or the coach of a top player, puts out a video or a book, or presents at a coaching conference and gives their subjective opinion (versus scientifically backed reasoning) on how to hit a squash ball.  One of the great things about working at the Princeton Summer Squash Camps for 18 years is that you get to see literally hundreds of coaches present and teach their version of squash technique – and this includes many coaches of world champions.  Obviously there are many contradictions, omissions, and obvious errors in the technique recommendations since they are based on “how I hit the ball” or “how I was taught to hit the ball”.

So although a teaching of technique based on squash-specific biomechanical research is not possible at this time, what is possible is a teaching of squash technique based on an empirical approach grounded in research into similar technical actions for which there is solid scientific evidence – the most classic example being a comparison of throwing a ball (for which there is a lot of research and practical coaching guides) with hitting a squash forehand drive.

heebthrow

The advent of easy video (filming, editing software and distribution) provides another way of empirically backing up our reasoning on squash technique.  If 95% of the top 20 use a shortened swing and lots of wrist flick (as seen in video examples) to hit a difficult ball out of the back-court, we can be much more confident in receiving advice than if we are told “this is what I do”.

Lastly, there are a set of universally accepted biomechanical principles which a coach can use to inform their technical interventions – analyzing, teaching or correcting.  The diagram below contains the Coaching Association of Canada’s conception of biomechanical principles important in the analysis of skills.  Ideally a coach should analyze and correct technique using both their experience as a player and a coach and a solid rationale based on biomechanical principles.  In future posts we will give some examples of how these basic principles relate to squash technique.

Seven General Biomechanical Principles for Sport

Seven General Biomechanical Principles for Sport

Application for Squash Coaches

  1. Go beyond the “this is what I do” rationale for stroke analysis and correction.
  2. Learn and use basic biomechanical principles in your technical coaching.
  3. Find and use a good tennis or general biomechanics reference.