In a prior blog posts we discussed the effects of stretching on fitness, performance and flexibility. We are often prescribing mobility exercises to restore movement to a joint or body region (thoracic spine and rib cage) in order to improve movement patterns for performance, pain relief, or as part of a weekly fitness program. While some patients or clients may require specific mobility work and stretching as a component of their home exercise program others may benefit from incorporating full range of motion strengthening exercises. These exercises provide benefits ranging from improved lean mass, strength, and coordination to reduced injury risk. Conversely, stretching has not been shown in the literature to reduce injury risk in either the short term (prior to performance) or long term (season) (Herbert et al. BMJ 2002).
One of the biggest barriers to performance of an effective exercise or rehabilitation program is time. Time is a finite resource and clinicians should construct programs that equally effective and efficient. In some cases, it may be possible to reduce time spent on stretching and mobility and replace these exercises with strengthening exercises focused on the lowering phase of the movement (eccentric). For example, performing a bicep curl includes lifting the weight toward your upper arm where the muscle shorterns (concentric) and controlling the weight back to the starting position where the muscle lengthens (eccentric).
Recent research has demonstrated improvements in muscle flexibility through a process called sarcomerogenesis. Sacromerogenesis defines the process in which the building blocks of muscles (sacromeres) are added in series following a flexibility or range of motion program. Specifically eccentric training seems to promote the process more effectively than concentric training (Lynn et al 1998). This process adds to the existing benefits of eccentric exercise on muscle performance and the reduction of injury risk.
A recent systematic review of the literature reviewed all prior research on eccentric training on limb flexibility (O’Sullivan et al. 2014). Authors reviewed 6 studies on eccentric training on limb flexibility and range of motion. They reported consistent, strong evidence on the positive impact of eccentric exercise on limb flexibility. These findings were drawn from studies on 3 different lower extremity muscle groups. Finally, the impact of these programs on flexibility outcomes was equal to those reported with static stretching.
In short, athletes and clients who are short on time should consider incorporating eccentric strengthening exercises to improve flexibility, increase muscle performance, and reduce injury risk