Movement Skills and Injury Prevention

Originally published in Hard2Guard Player Development Newsletter 5.22

Preventing or limiting injuries is one of the primary goals of strength and sports coaches. When a player is injured, he or she cannot help the team. The problem is often the lack of sophisticated, practical knowledge in terms of evaluating movement that can help spot a potential injury before it becomes a reality.

I worked an elite college camp years ago and sat with the athletic trainer as she pointed out girl after girl who was at risk because of her basic movement skills. I grew frustrated when she said that the coach said there was no time to do a session on movement skills at the camp, even though the camp was playing a time-waster (Land-See-Air) at the time.

We rely heavily on volunteer or near-volunteer coaches, so we will never reach a point where coaches have the expertise of athletic trainers in these manners. However, a recent study published by Stensrud et al. (2011) in the British Journal of Sports Medicinesuggests that a subjective assessment to determine poor knee control is as effective as a two-dimensional (2D) test of frontal plane knee motion. A previous study (McLean et al., 2005) identified three-dimensional motional analysis as the gold standard, but found a high correlation between 3-D and 2-D analysis. Therefore, a subjective assessment can be used to evaluate poor knee control in athletes.

The study used three tests: single-leg squat (SLS), single-leg vertical drop jump (SLVDJ) and two-leg vertical drop jump (VDJ). The SLVDJ used a 10cm box, but found poor results. The VDJ used a 30cm box jump. Interestingly, the SLS and VDJ identified different participants who showed poor knee control.

On the subjective assessment, the participants were scored 0 to 2:

“The score 0 indicated (A) no significant lateral tilt of the pelvis, (B) no obvious valgus motion of the knee and (C) no medial/lateral side-to-side movements of the knee during the performance. Players rated as 1 displayed (A) some lateral tilt of the pelvis, and/or (B) the knee moving slightly into a valgus position and/or (C) some medial/lateral side-to-side movements of the knee during the performance. Players rated as 2 displayed (A) lateral tilt of the pelvis, and/or (B) the knee moving clearly into a valgus position and/or (C) clear medial/lateral side-to- side movements of the knee” (Stensrud et al., 2011; p. 590).

Based on this rating scale, a coach could use a SLS or VDJ to evaluate his or her athletes. What does it mean or what to look for?

In this video of a VDJ, look at her knees when she lands: her knees are in a clear valgus position at landing. I would rate her a 2, and she is someone who would be termed “at-risk” in my non-medical opinion.

Depending on her training history and strength, she needs to re-learn how to jump and land, or she needs to develop more strength through her quadriceps, hamstrings and glutes or both. If she has good lower-body strength in the weight room, then she needs to learn to land properly and increase her elastic strength through plyometrics. Regardless, through the VDJ, a coach can identify her as “at-risk,” and if he or she lacks the knowledge to put together a program to correct the issues, the coach can direct her parents to a knowledgeable strength coach or physical therapist.

On the SLS, the coach watches for the same limitations. The first tell-tale sign is the athlete putting down her other foot. This shows a lack of balance and/or a lack of strength, either of which are worrying. To rule out balance, the coach could do a simple single-leg balance test – stand on one leg with the other leg raised and count how long the player can hold the position without wobbling; if the player cannot get to 20 seconds, balance is an issue. If balance is ruled out, you are looking at a strength deficiency. Also, the coach monitors the knee control as the player descends. The knee should track over the foot. I have seen athletes who end up with their hip pointing the opposite direction of their knee – I don’t even know how they can get to that position! I have tried to demonstrate it, and I cannot do it. If the knee moves inward into a valgus position, the athlete lacks the strength to control the movement and would be termed “at-risk.”

The study showed that different athletes failed different tests, meaning that using both tests is probably best to capture all the potential at-risk athletes. Also, the tests should identify the major limitation: the SLS is primarily strength and balance, while the VDJ could be technique, strength or elastic strength.

By Brian McCormick, PhD
Director of Coaching, Playmakers Basketball Development League
Author, The 21st Century Basketball Practice

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