Bobsleigh Sports Performance and Injury Prevention
By Dr. Murray RW Heber, Bsc(Kin), DC, CSCS, CCSS(C) resident
Head chiropractor for Bobsleigh Canada Skeleton Performance Enhancement Team
The topics of sports performance and injury prevention are popular ones proceeding the 2006 Olympic Winter Games. In Turin, Canada achieved a record number of medals with 24 medals, bettered only by Germany (29) and the United States (25). Canada had more fourth place finishes than any other nation with 13, as well as 8 fifth place finishes.
This prompts the question, what needs to be done in order to get those athletes on to the podium? Short-track speed skater Eric Bedard got fourth place by only 4-1,000ths of a second in the men’s 500m. Skier Kelly VanderBeek finished 3-100ths out of the bronze medal position in the women’s super-G. Francois Bourque missed the podium by 76-100ths in the men’s giant slalom. In the 4-man bobsled event, Pierre Leuders placed fourth by just 0.09 seconds, after 4 runs down the track. This works out to only 0.0225 seconds per run, and breaks down to 0.005625 seconds per athlete per run! In terms of units of time, these are minuscule differences. But these fractions of milliseconds make all the difference in the lives of the elite athlete. These fractions of time are the most difficult ones to attain in an athlete who is already so finely tuned. This brings into light the concept of “performance enhancement” and brings home the importance of injury prevention.
This article will discuss the concepts of sports performance and injury prevention in the bobsled athlete.
So what measures can we take to affect performance? Sporting equipment can improve aerodynamics by altering sled design, athlete position in the sled, and through the use of speed suits. Improved materials to make the sleds and their components will also help decrease run time. Athletes perform rigorous off-season and in-season training, as well as maintain a strict diet to keep their bodies in optimal shape. Many athletes take advantage of the health care system, integrating Massage and Stretching, Active Release Techniques, Acupuncture, Graston technique and Chiropractic into their regimes.
I will elaborate on each of these techniques and their usefulness in relation to increasing performance and decreasing injury.
Pre-event stretching… Friend or Foe?
There are three types of stretching; Static, Ballistic, and PNF (Proprioceptive Neuromuscular Facilitation) or Contract-Relax, depending on which nomenclature you use. Static stretches involve holding one position for more than 5-10 seconds. Ballistic stretches incorporate dynamic movements that approach the end of the range of motion. Examples include dynamic leg swings, hurdle mobility, and arm & torso rotations. PNF stretching (more appropriately named Contract-Relax stretching) involves partner assisted stretching, with both a period of stretching following by a period of muscle contraction.
Is stretching before an event of benefit or detriment? Stretching has been shown in numerous scientific journals to have a negative impact on performance. This is because they have an effect on muscle length, pliability and perceived exertion. Stretching changes the effective contractility range of a muscle fiber, making the muscle less contractile. Contract-relax stretches are most detrimental to performance, followed by static stretches, then ballistic stretches. Ballistic stretches appear to be the most ‘competition-friendly’ form of stretching, which is probably related to the fact that stretches are not held for extended periods and are within the muscles’ effective range of motion. Stretching after competition however, does not appear to have any detrimental effects, and most likely is of benefit is maintaining flexibility.
There are several different types of massage, from deep tissue/sports massage, which involves deep pressure and induces a significant change in tissue texture, to Shiatsu massage, which is more relaxing and not as deep, to Myofascial release, which attempts to free-up the muscle fascia interface. Similar to stretching, massage increases the pliability and flexibility of a muscle and it does so while sacrificing its excitability and contractility. Therefore both stretching and massage prior to activity tend to have a negative impact on performance.
Active Release Techniques ®
Active Release Technique (ART) is a functional approach to the treatment of injuries and performance limiting factors. ART involves moving a limb through an active Range of Motion (ROM) while tension is applied to specific structures, attempting to release adhesions at the muscle-fascia interface. No scientific research exists that correlates ART® with performance outcomes, but there exists much anecdotal evidence to support this claim. By providing functional improvements and restoration of muscle action, it is very likely that the performance of sport skills would be enhanced. If ART is used immediately prior to a sporting event, the therapist should be careful to avoid the use of too much pressure and should avoid holding lengthened positions for too long.
Contemporary Medical Acupuncture
There are several different forms of acupuncture. The two forms I will mention here are Traditional Chinese Acupuncture (TCM) and Contemporary Medical Acupuncture (CMA). Traditional Chinese Acupuncture entails needle insertion based on Chinese meridians, such as Yin and Yang points. The points are based on organ meridians that when combined result in an overall systemic response. There is much scientific research to support the use of TCM for a variety of different conditions from smoking cessation to osteoarthritis. Contemporary Medical Acupuncture is a program offered through McMaster University for health professionals. CMA uses an anatomical and neurological approach to needle insertion points. These points correspond with most of the traditional points, but are more specific to neuromusculoskeletal conditions. The specific source of pain and injury is more directly targeted in this form of treatment by inserting needles close to the involved nerves and muscular tissue. There exists much scientific literature to support this form of treatment for musculoskeletal conditions.
Graston Technique ®
Graston is an instrument-assisted form of soft-tissue treatment. This technique enables clinicians to effectively break down scar tissue and fascial restrictions. The Technique utilizes specially designed stainless steel instruments to specifically detect and effectively treat areas exhibiting soft tissue fibrosis or chronic inflammation. In scientific studies it has been shown to increase fibroblastic activity, which promotes the breakdown of scar tissue and the formation of new healthy tissue. This technique, when used properly, is a great adjunct to the treatment of soft-tissue injuries in the athlete. Because the technique breaks down scar tissue, a mild inflammatory reaction often follows a treatment, along with occasional bruising. For this reason, Graston technique is not recommended immediately before competition.
For most of the lay population, chiropractic has always been viewed as treatment for the spine. While this is true of all chiropractors, what most people do not realize is that chiropractors are trained to treat and understand all aspects of the human body. For example, Sports Chiropractors deal with all the muscles and joints in the body and how they influence performance. This type of chiropractor incorporates joint manipulation with various soft-tissue techniques to effectively treat athletic injuries. Sports Chiropractors complete a post-doctoral fellowship that incorporates research with classwork and hands-on experience with athletes to create a doctor that is literate in all types of sports-related injury. Sports Chiropractors not only learn how to recognize, treat, and prevent sports injury, but they are trained in performance enhancement methods such as gait analysis and soft-tissue treatment. Sports Chiropractors work with Olympic athletes and teams, and are often part of the core medical team at Olympic Games as well as several other international events. In order to be allowed access to the athlete village, as well as to be named to a core medical team, chiropractors must complete their post-doctoral fellowship education.
Focus on Biomechanics and Performance Enhancement
When discussing the sport of bobsled, it is important to gain an understanding of the types of demands that are placed on the athlete. For example, pushing a sled requires different mechanics than running or sprinting. The bobsled athlete does not run upright, like a sprinter would, and they must develop forward momentum to push a sled down the ice. As such, more emphasis is placed on the hip flexors, quads, glutes, and gastrocs/soleus for power development. As a result, hip and lumbopelvic stability is critical for maintaining force transmission from the lower extremity to the shoulders and into the sled.
High-intensity training typically results in the overdevelopment of certain groups of muscles and the relative weakness of others. These over-worked muscles will tighten up, which will result in a shortened range of motion and altered joint mechanics. In the bobsled athlete, one of the most common areas of concern is the hip. The Psoas muscle, which acts as a major hip flexor, will tighten up from repetitive maximal hip flexion while trying to drive the knee up with pushing. This is further aggravated by sitting tight in the sled with the hips in a maximally shortened position. This allows the hip flexors to tighten up between runs, which will decrease the power and efficiency subsequent runs. The psoas also has a reciprocal relationship is the Gluteus Maximus, which is the most powerful extensor of the hip. When pushing, the Glutes are the power muscles involved in hip extension and therefore forward progression of the sled. A tight Psoas will inhibit the strength and speed of contraction of the Glutes. This will result in weaker hip extension and less ‘drive’ when pushing. Yet another relationship exists between Psoas and the Hamstrings. In the presence of decreased hip extension power from the Glutes, now the Hamstrings must try to help with hip extension. The Hamstrings are primarily knee flexors and secondarily hip extensors, and they can only weakly contribute to overall hip extension. This new demand places a lot of stress on the hamstrings and they get over-worked and then tighten up, making them more prone to injury.
Other biomechanical adaptations resulting from tight hip flexors exist. With the decreased ROM of hip extension, the low back extends to allow for the ‘normal’ amount of extension. This increasing low back extension results in an increasing ‘sway-back’, weakened abdominals, tight hamstrings and low back pain. The Psoas and Rectus Femoris also have a reciprocal relationship. The Rectus Femoris is the top-most quadricep muscle, which crosses both the knee joint and the hip joint. As such, it acts as a secondary hip flexor. Therefore when psoas is tight, the rectus femoris helps with hip flexion. Again this results in a shorter, tighter Rectus Femoris which may be predisposed to injury.
These biomechanical errors and adaptations bring to light the importance of core stability. What is core stability? Core stability is an umbrella term for the tightening of the abdominal and spinal musculature that allow for a more ‘stable’ lumbopelvic region. This is critical for the continuity of force development in the lower extremity to be transmitted to the upper extremity. Traditional Core Exercises include the Bridge, the Plank, the ‘dead bug’, the ‘bird dog’, as well as performing exercises on a gym-ball. But did you know that simply doing core exercises may not be enough to actually strengthen the ‘core’? The S.A.I.D. principle (Specific Adaptation to Imposed Demand) describes how the body will adapt to the stresses placed upon it. To create an adaptation, you must impose a specific demand in the form of exercise. Your body will find a way to adapt to an imposed demand, whether or not it is the specific adaptation you intend. For example, if you perform the same core exercises over and over again, without any change or increased demand, your body will adapt to the exercise and you will no longer be making any further gains in strength. To that same effect, if your core strength is lacking, your body can find a way to perform the exercise without challenging the core.
PLANK PICTURE COMING SOON
For example, consider the plank exercise. The hip flexors and shoulder musculature can maintain the plank position while the core muscles only have to do minimal work to maintain the position. Similarly, the bridge exercise (pictured below) is aimed at strengthening the Glutes, but as we have already learned, the Hamstrings can attempt to compensate for a relative weakness. Both these compensations result in furthering the relative weakness of the core in comparison to those muscles that can ‘cheat’ at maintaining the position.
BRIDGE PICTURE COMING SOON
The net result is a weak core with resultant loss of power transmission from the legs to the sled. Therefore it is important that when doing core exercises, you must activate the core. This is done by firing the muscles that create lumbopelvic stability, namely the lumbar Multifidus and the deep abdominal musculature. Exercises that promote co-contraction of these sets of muscles are most effective in increasing the strength of the core.
In the bobsled athlete, injury prevention is of utmost importance. Proper training and proper recovery as well as understanding the body’s adaptive process and knowing the first signs of adaptation are key in this process. Steps the bobsled athlete can take include:
• Stretching hip flexors and hamstrings daily
• Performing core stability exercises using the core stabilizers
• Keeping the adductors and IlioTibial Band stretched out
These simple steps will aid in injury prevention as well as in the development of core stability.
In a world where the gold medal comes down to a matter of milliseconds, it is the most trained, efficient, healthy, and stable athletes who will stand proudly on top of the podium.
STRETCHING PICTURES COMING SOON