It’s become increasingly popular in physical culture circles to see sweeping statements such as “stretching is pointless” or “another study confirms stretching is useless,” based on popular interpretation of stretching and flexibility research. Although this trend has picked up steam, the purported evidence is not as solid as it is sold to be. Not surprisingly, martial artists have been a pretty fertile bed for this trend. There are good reasons to re-evaluate the place of stretching in a training program, as it does appear that the standard notions on when, how and why to stretch are not as useful as we have been taught. In determining whether or not the “stretching is useless” approach is accurate, we need to be careful in examining what questions the research sets out to ask and how it goes about answering them. The type of activity that stretching may be used for is also an important consideration; recognizing when it is useful according to the training situation or individual is of more value than simply writing it off.
In a nutshell, reviews of quality research findings indicate that static stretching (holding at the point of tension for >30 sec) before training can promote a loss of explosiveness and potentially increase joint instability, but that regular stretching between sessions has no negative effect, and may actually promote improvements in explosiveness and hypertrophy (Weldon & Hill, 2003; Thacker, et al., 2004; Shrier, 2004; Gremion, 2005). There are some holes in the research that determine the implications about what it means for those of us on the mat. The first of these is that not all research is the same in scope or quality. Reading a small study or one based a limited population and then declaring that the results “scientifically prove” something is like saying that since Lucky Charms are vitamin fortified, they are scientifically proven to be a healthy breakfast choice (they’re not, by the way). Here are some red flags for general relevance of research: a small group was sampled; only athletes of a given sport were sampled; only a given age range were sampled; only one gender or another was sampled.
In a comprehensive review, Thacker & colleagues (2004) found no significant protective effect of stretching when used pre or post exercise. They also found that the potential adverse effects and the beneficial effects are inconsistently reported. Their findings point out another significant limitation on the research: posture during stretching and whether or not the subjects held a stretch for the optimal duration (static of PNF). The former is significant; if subjects were using the common approach of ambling through different positions after a few seconds, it is likely that the stretch was impaired, providing invalid data.
Shrier’s (2004) meta analysis of 23 quality studies reports that pre-exercise static, ballistic and PNF stretching diminished performance, measured by torque, peak force and jump height. Before high intensity activities, like heavy sparring, competition, max strength or power training, a reduction in peak force and rate of force development could be a limitation, or invitation to injury for a martial artist. Seemingly paradoxically, regular (not pre-exercise) stretching appears to enhance performance, with no negative effects reported. Roughly a third of studies reviewed showed an improvement in performance after an acute bout of stretching, and no decrease as a result of regular stretching. This observation has led to the new common wisdom of “static stretching after and between exercise/training sessions.” Shrier’s findings are applicable to a wide population range, including athletes, non-athletes, with warm up and with out, and males and females.
The discrepancies in stretching data come from use of different protocols, test designs, and populations used in the studies in question- hence, we have studies that provide evidence indicating that stretching in general does improve performance and reduce injury risk, and that it does not (as evidenced in reviews by Weldon & Hill, 2003; Thacker, et al., 2004; Shrier, 2004; Gremion, 2005). A significant limitation in virtually all research is the fact that performance in actual competition cannot be directly measured, leaving indirect measurement (jump height, maximal ROM, etc.) as the primary means of assessment (although it can be argued that studies comparing specific injury rates in stretching intervention vs. non-intervention groups are more direct). Sometimes the measurements used are more convenient than they are relevant . For example, absolute ROM or isometric strength measures are not universal direct predictors of performance ability or injury risk, or one’s ability on the field or mat.
Another gray area that needs to be clarified is whether or not the efficacy of stretching is based on an injury prevention goal or a performance goal. How one judges “success” of stretching for performance depends on the goals and limitations of the individual in question: does the individual just force and speed, or is a lack of tissue/joint mobility a limiting factor in producing those goals? Not all individuals will need This points to the broader need to clarify whether or not a study evaluated stretching as injury prevention or as performance enhancement. Conditioning that aims to resolve a movement impairment and conditioning that aims to increase an athletic attribute are typically different in programming and execution. So in the case of a use of static stretching, research evidence might support that it is or is not helpful; but this is not indicative of a limitation of stretching unless context is provided. Self myofascial release (SMR, “foam rolling”) is so far conspicuously absent from the research discussions, although it has gained considerable popularity in the past couple of years. SMR exploits a different muscle receptor reflex, and although the neuromuscular and mechanical effects can be helpful in enhancing tissue quality, the research simply hasn’t been done yet.
Should martial artists stretch at all? Before or after training? How often? Should they use static stretching at all? Keeping in mind that different stretching modalities have different physiological results (static stretching being most of the focus here), and that training/performance goals dictate what aspect of stretching is useful and when, the best answer might not be “yes or no,” but some guidelines about how it can be useful:
- Dynamic stretching and SMR (self myofascial release) pre-training/conditioning
- Static stretching and PNF post-training/conditioning, or as part of a specific corrective program
- Dynamic, static and SMR between training/conditioning sessions
- PNF once to twice per week, not before training or conditioning sessions
*unless under the direction of a qualified therapist
For martial artists and instructors planning sessions, some latitude in applying these guidelines is also useful. If a training session is going to be low-impact and light, there is likely no harm in static stretching before hand, especially if there are movement quality issues that might be an obstacle to the training goals. Following a high impact session with lots of partner and/or ground contact, static stretching and foam rolling are important for promoting circulation to affected areas (although we should avoid foam rolling seriously bruised tissue) and keeping the muscles from getting hypertonic (shortened). In a situation with multiple successive bouts, like a tournament or a training camp, dynamic and static stretching as well as foam rolling can preserve tissue mobility between bouts of activity, although it is probably a good idea to avoid static stretching or prolonged SMR <1 hour before to avoid the potential for reductions in force production and joint stability (research is still out on the last bit).