ACL Injuries, Degrees of Freedom & Jump Training

Last month, the New York Times ran another article on ACL injuries featuring UConn guard Caroline Doty. After explaining some issues related to the incidence of the injuries, the author takes a shot at volunteer youth coaches:

A number of coaches and trainers have criticized youth development in sports, where far more attention is paid to winning and athletic skills than to injury prevention. Auriemma and other coaches also wonder whether girls are reinforcing poor biomechanical behavior by specializing in a sport too soon.

Is the issue of winning at youth levels a problem? Yes. However, it is a stretch to blame volunteer coaches who receive no training for injuries when million-dollar college coaches continue to ignore the problem. I worked the Cal Elite Basketball Camp one summer. The campers were playing a time-waster called “Land-Sea-Air” that is very popular with college camps on the West Coast.

I sat down next to the athletic trainer, and she pointed out girls who were at-risk for ACL injuries due to their anatomy or biomechanics. I asked her why she did not help the players; I was ready to stop the entire camp to have her address the issue with these girls. She said that she had asked the coach, but the coach did not think there was time to do any kind of movement analysis or movement education with the players. So, in summary, a college coach has time for time-waster games, but not actual activities to decrease the campers’ potential for injury (also, if college coaches did not offer scholarships to 8th graders, maybe they would have less incentive to specialize).

Vern Gambetta wrote a follow-up to the article that pointed out its flaws. Essentially, the article describes efforts by the UConn trainer to limit the motion and create perfect landings and cuts.

When landing, UConn players are taught by the trainer Rosemary Ragle to bend at the hips and knees to softly absorb the load, keeping their knees behind the toes, striking the ground toe to heel. The knee should be in a neutral position; ideally, Tennessee’s Moshak said, the center of the kneecap should be aligned with the second toe.

This is how we approach skill development, whether shooting or landing from a jump. We teach athletes to freeze the degrees of freedom at the joint and restrict movements. However, training these perfect movements often occurs at a sub-optimal speed. Is it possible to land or stop perfectly at high rates of speed?

The article even explains how the UConn coaching staff attempts to prevent awkward movements:

Chris Dailey, UConn’s associate head coach, says players are taught that if they cannot pass the ball before a teammate reaches the opponent’s free-throw line on the fast break, not to attempt the play. This is to keep players from having to stop suddenly to avoid going out of bounds or to make a move that puts their bodies in an awkward position.

After the article was posted, a college squash coach tweeted that he avoids “unpredictable agility” drills during training.

These solutions miss the point. What happens when a UConn guard feels some pressure and forgets the rule and a player has to make a sudden move? What happens when a squash player has to react unexpectedly to an opponent’s shot or movement? What happens if the player lands with her knee in front of her foot?

Gambetta emphasizes strength, and especially single-leg strength, as many of these injuries occur when a player lands or cuts on one leg. I flipped through some volleyball pictures, and based on the photos, it appeared that few hitters would land on two feet simultaneously.

However, the assumption, and the instruction, is to land on two feet. Therefore, volleyball players practice landing on two feet. However, what happens when they don’t? What happens when the hitter receives a bad set and rather than letting it go and losing the point, she tries to make a play and contorts her body so she can hit with her right hand on the left side of her body?

She lands off-balance, with all her weight on her left leg and her center of mass moving to the outside of her left leg. Sure, it is easy to say land on two feet or let the set go and lose the point, but what happens in reality?

Rather than eliminate the movements, players need to prepare for them. As Gambetta writes, part of the preparation is greater strength training and greater emphasis on single-leg strength. However, the answer lies beyond strength. Players need to train in compromised positions.

This is counterintuitive, kind of like the degrees of freedom example with the rifle from 5.11. If the goal of training is to reduce injuries, why would you train in a position that is more likely to cause injuries? The answer is because it will happen in a game, and if it will happen in a game, it should be trained first.

Rather than trying to freeze the degrees of freedom at the ankle, knee and hip joints at landing, athletes should train in situations that expand the degrees of freedom. Look at the picture of Rose – he is positioned perfectly to cut. However, how often do players train their body in a similar position?

Look at the second picture of Rose. Again, his left leg is positioned well to cut; however, look at the twist in his upper body. This is a real game move. How many athletes practice putting their bodies in this position?

The article’s answer is not to make these movements. They want to restrict the degrees of freedom and limit the possible movements available to a player. Instead, I suggest expanding the possible movements, training all the movements, not just the ideal, and developing strength through these movements.

As I wrote last week, non-experts freeze their degrees of freedom to eliminate gross errors and to become more consistent. The concepts in the article essentially cover this transition. Players first move from wild technique with knees and feet everywhere to a very controlled landing with their knee right over their toes and their hips sitting back. To improve further, however, they need to add the degrees of freedom – however, when an expert adds the degrees of freedom, in comparison to a novice, she controls the movement with greater precision and the joints counterbalance each other. Reduced movement at the knee leads to increased movement at the ankle or hip.

If coaches followed the article, movements like those in the Rose pictures would be disallowed. I know because I was told not to teach these movements at a camp because I was told that females are not capable (this by a prominent female basketball coach). At the time, I thought she meant that girls were not capable of performing the skill as I demonstrated, and I disagreed, as I had 9 and 10 year-olds at home performing the skill. Now, I think she meant this – the action of getting the foot outside the knee and the knee outside the hip. I think she wanted to freeze their degrees of freedom. She wanted players to stop on two feet to change directions on a crossover dribble rather than cutting hard as Rose illustrates in picture one (assuming from his hand placement that he is initiating a crossover dribble, which may not be accurate, but his body would be in a similar position if he was).

Rather than restrict movement and cross our fingers and hope that it does not happen in a game, we need to develop strength in all possible movements and positions. If we train and develop strength through more than one position, athletes are more likely to adapt to other movements or positions. In shooting, if you practice one specific shot over and over, you may not be able to adapt if you jump higher or have to shoot over a defender. However, if you constantly practice new shots, you can adapt to other shots within the spectrum.

Similarly, if you only practice the perfect landing,  you may not be able to adjust to other landings in the course of the game. If you adjust your training and incorporate different skills, you may be able to adapt to different situations in a game.

Below is a video of jump training from Train 4 The Game in Austin, Texas. Notice, they train transverse jumps and hops and unorthodox hops. They train through positions that players will see in a game that are not commonly incorporated into training. We used some of these exercises in our pre-practice dynamic warm-ups last season. By increasing the number of movements in which athletes can move safely, we reduce the athlete’s risk of injury. Artificially limiting movements and hoping they do not occur in a game is not a prevention program and more so than prayer.

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