By Kelsey Jack, PT
My ballet teacher once told me that given a choice between having strength and flexibility, she would choose strength. This has always stuck with me as there is such an emphasis on flexibility within the dance world that often there is a lack of focus on building the strength required to make use of that flexibility. This enhanced focus on flexibility instead of a balance between strength and flexibility creates muscle imbalances. If dancers work to improve their flexibility and ignore balancing the strength around the joints, it leaves the dancer vulnerable to injury.
Why is balancing strength and flexibility important?
Stability is provided to joints from a combination of passive and active structures. Passive structures include the bones that make up the joint and the ligaments that surround it and support it. Active structures are the muscles and tendons that act to both maintain stability and move the joint. Focusing on passive, static stretching, as is often the case in dance, can lead to instability of joints as the ligaments that are meant to stabilize the joint become stretched out and no longer provide joint support.
Flexibility, or range of motion can be divided into two categories: passive and active. Passive range of motion is demonstrated by how high a dancer is able to lift their leg using their hands whereas active range of motion is how high a dancer is able to lift their leg using their hip muscles and is demonstrated by doing a step like a developpé. Practically speaking, flexibility without strength limits active range of motion and will hinder the height of legs when performing steps that involve controlled movements and sustained positions.
Back bends are a good example of a movement that is common in dance where strength is required to balance the flexibility of the spine. Dancers without good core strength and control will hinge through their spine, relying on one or two segments to gain all of their movement through. This leaves the spine vulnerable to injury as the ligaments and discs are relied on for support. Ideally when doing a back bend the spine should form a “C” curve. Many teachers instruct dancers to breathe up and extend through the top of their head into their back bend to encourage control into this movement pattern. Engagement of the abdominals and stabilizer muscles of the spine are required to move through each segment of the spine in a way that supports the passive structures of the back to create the desired curve. It is subtle differences such as these in how a dancer moves, using strength to control their flexibility, that improves the quality of movement and decrease the future risk of injury.
Evidence to support strengthening to increase flexibility
As dancers are often concerned about their hip flexibility, a study was done looking into the best way to increase hip active range of motion. The researchers compared three stretching programs over a six week period. The first group of dancers completed a strengthening program where they worked at strengthening their hip flexors at the end of their available range of motion. The second group completed a “light” stretching program for their gluteals, hamstrings, calves, and quadriceps muscles, holding each stretch for 1 minute. This group was asked to perform stretches at an intensity of 3/10 on a scale where 0 is no stretch and 10 is an intense stretch that elicits a burning sensation. The third group performed the same stretches but at a “moderate-high” intensity which was rated as 8/10 on the same scale. The study found that all three groups had an increase in their passive range of motion but only the strength training and the low intensity stretching groups improved their active range of motion. The strengthening group saw the greatest improvements in both passive and active range of motion which is explained by the hamstrings relaxing as the hip flexor is contracted. This allows the hamstring to lengthen while the hip flexor is strengthened. Intense stretching without strengthening (as in the high intensity group) leads to lengthened, weakened muscles which functionally hinder a dancer’s ability to make use of their range of motion. This study demonstrates that exercises that specifically train the hip flexors progress flexibility in a way that translates into dance.
Strengthening allows dancers to maximize their flexibility without compromising the integrity of their passive support structures and increasing their risk of injury. A physiotherapist can assess a dancer’s strength and flexibility and develop a program that will safely allow a dancer to increase their flexibility while strengthening the muscles needed to support their joints, improve performance, and decrease risk of future injury.
Wyon MA, Smith A, Koutedakis Y. A Comparison of Strength and Stretch Interventions on Active and Passive Ranges of Movement in Dancers: A Randomized Controlled Trial. Journal of Strength and Conditioning Research. 2013. 27(11)3053.