Tuesday, October 21, 2014

What is an Overuse Injury?

           Taking time out each day to relax and renew is essential to living well. ~Judith Hanson Lasater

           Any type of physical activity is accompanied by a risk of injury, and dance is no exception. Research done on dancers reports injury rates as high as 95% in professional ballet dancers and as high as 82% in professional contemporary dancers. Even recreational dancers experience injuries. A 2010 study reported that 42.6% of female recreational dancers under the age of 16 experienced an injury.
           
            Some injuries are acute, meaning they are due to one specific traumatic event like a fall, a collision or a poor landing that leads to a fracture, a sprain, a dislocation, or a muscle strain. These injuries are treated right away and have a predictable recovery time – a sprain may require 1-2 weeks in an aircast followed by physical therapy, and a fracture may require a cast for 6 weeks followed by physical therapy.

            Chronic injuries, however, are less predictable. These injuries happen over a long period of time. Unfortunately, they are the most common injuries among dancers and are the most difficult and challenging injuries to treat.

            Exercise places stress upon our bones, tendons, and muscles. This type of stress is a good thing because it causes changes within our body. Slight tears occur in muscles so that the body can rebuild muscles and create stronger tissue. When stress is placed on bones, the body’s response is to add another layer of protection by depositing collagen molecules on bone surfaces to form a matrix that hardens into another layer of bone.

            Unfortunately, when dancers increase the amount of hours they dance, add rehearsal hours into their schedules, or try to add extra classes to get back in shape quickly after a break, they often do not allow the body enough time to rest and go through the rebuilding process before it is once again placed under stress.  The result of this imbalance between time spent dancing and time spent resting is repetitive small traumas in the body tissues that never quite get repaired.

            Eventually, these micro-traumas will accumulate, and the dancer will begin to experience constant pain or aching in specific parts of the body that turn out to be tendinitis, shinsplints or stress fractures. When dancers continue to work when the body is tired, they are also more likely to compensate by using incorrect muscles and disupting skeletal alignment and not paying careful attention to proper technique.

            Once identified, these injuries often require complete rest, which results in missed classes, rehearsals, and, maybe even, performances. Since the injury developed over time, it makes sense it will also need time to heal.

              Some ways to avoid overuse injuries are to listen to our bodies when they are tired, constantly evaluate our technique, and be mindful about our alignment. Doing these things will help to minimize the risk of a dancer developing an overuse injury and help dancers to dance without pain.
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Liederbach, M. Schanfein, L. & Kremenic, I. (2013) What is known about the effect of
         fatigue on  injury occurrence among dancers? Journal of Dance Medicineand Science. 
          17:3,101-8.
Murgia, C. (2013) Overuse, tissue fatigue, and injuries. Journal of Dance Medicine and 
          Science. 17:3, 92-100.
Shah, S., Weiss, D. & Burchette, R.  (2012) Injuries in professional modern dancers: 
           incidence, risk factors and management.  Journal of Dance Medicine and Science. 
           16:1, 17-25.
Steinberg, N., Siev-ner, I.,Peleg, S., Dar, G., Masharawi, Y., Zeev, A. & Hershkovitz, I.
           (2012): Extrinsic and intrinsic risk factors associated with injuries in young dancers
           aged 8–16 years, Journal of Sports Sciences.  30:5, 485-495.

Monday, August 18, 2014

Exercise as Medicine for Concussion

Today's follow up post on concussions discusses research on concussion recovery and is written by Judie Clark, a colleague of mine who is both a dance educator and an exercise physiologist who has been doing extensive research on concussions….


     Aerobic exercise may help reduce the symptoms of concussion in post concussive patients, according to a new study. The finding challenges the traditional recommendation of complete rest (both physically and mentally) and suggests that daily low level activity, 10-15 minutes, may diminish prolonged symptoms of concussion.

     For the study, “Exercise Intolerance in Individuals With Postconcussion Syndrome”, which was published last fall in the Journal of Athletic Training, researchers at Canisius College recruited 34 concussed males and females, ages 25.9 + 10.9 yrs. On average, the participants had suffered a concussion 226 days earlier.

     Postconcussive syndrome (PCS) is a diagnosis that is given when concussion symptoms are still present and not subsiding, at least three weeks after a concussion occurs.  According to the World Health Organization PCS includes a history of traumatic brain injury with at least three self reported symptoms. Symptoms of concussion include: headache, fatigue, dizziness, difficulty concentrating, intolerance of stress or light, feeling in a fog, and insomnia.

     The study participants were tested by walking on a treadmill. Blood pressure measurements were taken every two minutes and heart rate was recorded every minute. The test ended as soon as any concussion symptoms grew worse. The control group in this study was made up of individuals who had no history of traumatic brain injury. PCS participants were unable to exercise as long as the uninjured control group.

     For some time, researchers have known that small amounts of exercise that do not increase symptoms and treadmill testing are safe and effective in the evaluation of concussion in athletes  and determining when they can return to sports (Leddy et al. 2010). Clinicians have access to tangible data like heart rate, blood pressure while carefully monitoring concussion symptoms such as headache while patients are on a treadmill, similar to a cardiac stress test evaluation.  An asymptomatic response to graded exercise can be and is a key decisive factor for determining return to sport and recovery from concussion.

     Noticeably different than its predecessors, the Zurich Guidelines are a stepwise approach that recommends return to play guidelines should progress in 24 hour increments. The athlete should be asymptomatic before advancing to the next level of exertion, if symptoms are exacerbated, the athlete returns to the previous level (Guskiewicz & Valovich McLeod, 2011). The Zurich stepwise return-to-play guidelines are based on consensus and not evidence based studies; they are subjective and vague about intensity and duration. 

     Cobb & Battin, (2004) suggested that current return to play guidelines may be “too lenient to protect a student from Second Impact Syndrome (SIS)”. Second Impact Syndrome is also called “second impact”, “subsequent head injury”, and “recurrent traumatic brain injury” in the literature. Second Impact Syndrome is a rapid swelling of the brain that can occur hours, days, or weeks after the first brain injury (Cobb & Battin, 2004). Cantu (1996) suggests, “athletes that sustain a concussion are four times more likely to sustain another concussion than those who never had a concussion”.  The subject of SIS is currently controversial among researchers but they agree that edema is more likely in the younger brain rather than the more mature brain (Guskiewicz & Valovich McLeod, 2011).
It is agreed that patients must rest mentally and physically during the acute phase of concussion, 1-3 weeks.  Beyond three weeks complete rest even “cocooning” may not be the best approach.  Karl Kozlowski, PhD, the lead researcher of this study, is developing an individually tailored intervention for athletes to stay in condition, without exacerbating symptoms, while recovering from PCS.

     According to researchers, moderate physical activity actually restores the brain’s auto regulation mechanism, which increases blood flow, and simulates neurogenesis in the hippocampus, the memory center, which stimulates the growth of new neurons, or nerve cells. Cerebral auto regulation, the system that maintains cerebral blood flow, may be dysfunctional in people with concussion and may return to normal with controlled exercise.
Regulated exercise allowed for recovery of participants in the study. All but two concussed participants were free of symptoms at follow up. Athletes recovered more quickly (11-36 days) than non athletes (41-112 days). A limitation in this study is the small sample size.
Daily moderate exercise, in a controlled or clinical environment may not only be helpful in the monitoring and recovery from PCS, but a more accurate screening tool for determining return to play.  Additionally, controlled graded treadmill testing may be a valuable therapy for depression, cognitive function, neurodegenerative diseases such as Alzheimer’s (Smith et al., 2011),  and may help differentiate PCS from other diagnoses such as migraine, post traumatic stress disorder, and depression which share similar symptoms.           



Ms. Clark has enjoyed a long career as a dance educator. Ms. Clark has taught as an adjunct professor at Dean College, Nichols College, The University of New Haven, Central Connecticut State University, and Albertus Magnus College. She has a Bachelors of Science in Dance from SUNY Brockport and studied Movement Analysis at The Laban Institute of Movement Studies and Harkness Center for Dance Injuries/ NYU Hospital for Joint Diseases in NYC, New York. Ms. Clark performed over 600 clinical hours as an exercise physiologist, with late stage HIV/ AIDS patients in New Haven. Currently, Ms. Clark is Masters Candidate at Southern Connecticut State University and is on the nursing staff at Yale New Haven Hospital. You can take a look at Judie's fitness blog by clicking here.