Stretching is used as a standard practise for recreational and competitive sports, rehabilitation and by active individuals. The term nowadays falls under the broader term of mobility, which aims to improve the range of movement (ROM) available at a joint, a well-known component to physical fitness and wellbeing.
There are a number of ways to practice mobility such as dynamic, static and PNF stretching, as well as trigger ball and foam rolling.
- Static stretching: The muscle is lengthened in a specific position to a point where tension is felt and held.
- Dynamic stretching: Involves actively moving the muscle in and out of its full range of movement
- PNF or ‘pre-stretch contraction’: Stretch the muscle up to the point of responsive contraction and hold, then lengthen the muscle further once contraction is eased.
- Trigger ball and foam rolling: A self-massage technique where the soft muscle tissue is rolled and compressed on using a ball or foam roller.
The optimal duration to hold a static stretch can vary. Research has shown that a significant increase in hamstring ROM can be achieved at a 30 second hold (Bandy et al., 1997), whilst increasing the duration up to 60 seconds has shown no significant improvement, and 15 seconds has had limited effect on flexibility (Bandy et al., 1994). Frequency of static stretching throughout the day can also be important. Significant gains in hip flexion were found from 6 weeks of 6 x 10 and 2 x 30 second holds, that were repeated twice a day (Cipriani et al., 2003). Furthermore, a review into the effectiveness of PNF versus static stretching, found equal improvements in hip ROM and hamstring flexibility (Lempke et al., 2018). Performing these exercises for 6 to 8 weeks have been found sufficient.
Research into the efficacy of these stretching methods on injury risk in sport is extensive, however the data is somewhat inconclusive. A review looking into the impact of stretching on sports injury found little to no effect on injury risk (Thacker et al., 2005). Similarly, Witvrouw et al (2004) argued there was insufficient data to support either for or against. However, it is important to note, there are huge irregularities across the research for compliance, participants, stretching procedure, injury type and type of sport. Making the results of the research difficult to apply to the general populations.
Despite these findings, restricted ROM can be unfavourable. Muscle tightness creates tension and impairs its ability to contract effectively (Walker 2013). Shortened muscles can contribute to muscle and joint pain; reduced movement control, and ultimately may affect sport performance.
In addition, restricted ROM through muscle tightness can lead to a muscle imbalance. Our muscles are in a kinetic chain, and one tightness or weakness can stimulate another one further down the line. For example, hip flexibility and strength are noted as risk factors for quadricep injury (Vigotsky et al., 2015), and limited quadricep flexibility has been identified as a significant predictor to sustaining a hamstring injury in football (Gabbe et al., 2005). Football players that had the lowest flexibility at the knee measured using the Thomas Test, were less likely to complete the season without an injury. Furthermore, poor mobility at the hip can lead to a limited hip rotation capacity, which has been suggested to increase stress throughout the lower body, and increase the risk of knee and ankle injuries (João et al., 2008).
The use of foam rolling has been found to significantly increase the range of motion at the hip, and even further when combined with static stretching (Mohr et al., 2014). It’s role in pre and post exercise routines have shown improvements to muscle soreness and strain injuries. Furthermore, it’s been found to increase the range of movement at the hip and ankle, and promote faster recovery from training (Cheatham et al., 2015), which in turn can possibly help to prevent musculoskeletal (MSK) problems later down the line.
Notably, not all sports require the same levels of flexibility for performance, but those that exclude this training could potentially limit their physical capacity and put themselves at risk of injury. Looking at measures of mobility at key joints can help to determine when someone is ready to return to sport.
Optimi Health supports the use of mobility practises for joint health, recovery and to support the return to play process following injury.