Strength development can assist in day-to-day life, sporting performance and even health markers. When we consider developing an individual, both strength and flexibility are important components of health, and need to be equally developed. However, does one effect the other? Can strength training and flexibility be developed together? There is a common conception that frequent strength training is associated with a reduction in flexibility, or that flexible individuals will struggle to develop maximal strength.
It’s now quite a well-established fact that static stretching prior to strength training influences muscular recruitment, load capacity and even markers of power. However is there a way of developing both fitness components harmoniously?
Previous research has established that strength training in a circuit fashion has actually improved the flexibility of sedentary adult women (Monteiro et al., 2011). Logically this seems plausible; when we consider that squat and hinge patterns provide a primitive yet critical form of flexibility training, it becomes apparent that the notion of completing compound movements with technical efficiency requires a tremendous level of flexibility. What’s more, rather than stretching through isolated movements, developing flexibility through the movement patterns provides a more functional enhancement of the individual’s flexability.
Siamo et al., (2012) recently confirmed these findings demonstrating improved flexibility through a 16 week strength training regime. It is now generally regarded that following 6 months of strength training, flexibility will be enhanced, providing the personal trainer is proficient in coaching the movements, and correcting form where necessary.
When we look closer at strength training, one of the main reasons for loss of flexibility may lay in the range of motion completed for the movement. When we visit the gym, a common error noted in many movements is a poor range of motion, particularly in strength training where significant loads are employed. Overloading clients, forcing movements to be completed in poor ranges, may be one of the key contributing factors to reduced or poor flexibility.
However despite this, one can only assume a cause and effect. It may be that we as personal trainers and coaches should include more flexibility training into strength training regimes. Until recently little research has examined the effects of varying levels of flexibility and strength in a training program, let alone their interaction at varying levels. Recently Leite et al., (2015) examined influences of strength and flexibility training combined or isolated on strength and flexibility gains. The study involved separating individuals into 4 groups:
- Strength training only
- Flexibility training only
- Strength training with flexability training
- Flexibility training with strength training
The researchers examined 10RM strength in the bench press and leg press, as well as the sit and reach test and goniometry. Interestingly all groups, apart from the flexibility only group, improved in bench press strength. The researchers did not note any further significant differences between the groups, however slightly different treatment effects were associated which each group. Key points:
- The largest treatment effects were observed in the strength group who developed strength the most; the flexibility group had the lowest level of overall strength development
- Both combination groups demonstrated lower strength development scores than the strength only training group
- No differences in flexibility where observed in any group, in any of the comparisons
In conclusion it appears that combining strength and flexibility training is not detrimental to flexibility, however combining the two forms of training may reduce the rate of strength development. Whereas strength training did not appear to negatively effect flexibility development. However caution should be noted as the sample size per group was relatively low and further long term studies are required to asses the long term effects of strength training on flexibility.