Mobility exercises designed to improve range of motion within an affected joint or tissue are a valuable part of any rehabilitation program. Previously clinicians prescribed various bouts (3 x 30 seconds) of static stretching in an attempt to lengthen short muscles. Current research has shown these prescriptions are ineffective at changing muscle length and instead alter the stretch tolerance of the muscle. Thus individuals who stretch more frequently, have an increased tolerance to stretch, and therefore greater range of motion. Conversely, eccentric exercise has been shown to not only develop muscle strength and size, but also change the structure of the muscle improving its’ true length. Further, in randomized, controlled trials eccentric exercise produces greater gains in hamstring flexibility than static stretching alone. A recent study suggests this may also be true for the quadriceps.
Alonso-Fernandez and colleagues studied the effects of 8 weeks of eccentric quadricep training on muscle strength, cross sectional area, and flexibility (J Sports Med Phys Fitness. 2011). Authors placed 26 participants underwent pre and post training testing, as well as, a 4 week detraining period to determine the lasting effects of this exercise program. As expected, eccentric quadriceps training led to gains in quadriceps strength and muscle size. Consistent with prior research on the hamstrings, this eccentric training also improved muscle length and flexibility measurements. Reinforcing a commonly held belief “strengthen to lengthen”. in addition, all measures of muscle performance decreased following the 4 week detraining period. This study further supports our understanding of muscle architecture and the forces required to make a significant change in muscle tissue.