Have you ever been able to touch your toes? Many people who cannot achieve this merely put it to genetics. “I’m not naturally flexible”. The truth is, many people are not naturally flexible, they simply put in the time to develop their flexibility. Of course, there are those who are naturally flexible, but this doesn’t mean that you can’t achieve the same suppleness. To develop flexibility, like developing muscle, you have to spend time working on that specific goal. 10-15 minutes of stretching after your workout is not enough to GAIN flexibility. You need to approach stretching as you would any other form of exercise; sets, reps, time under tension.
When discussing mobility and flexibility, we must first differentiate between “tight” and “shortened” muscles. Many people believe when they stretch they are lengthening the sarcomeres, the protein fibers that make up muscle, eventually increasing sarcomeres (sarcomerogenesis)1. However, what is more often the case is that the nervous system is relaxing and letting go of tightness as it adapts to the new range. When the body remains in certain positions for extended times, or if there are imbalances, the nervous system will adapt and increase tone to muscle. This creates “tightness”, not a true shortening of the muscle. By stretching we send signals to the nervous system that this new range is safe and it will reduce tone as it becomes more comfortable within the new ranges2. This will require repeated bouts of stimulus for the adaptation to remain.
However, when the muscle fibers remain in a shortened overly tonic state, they will eventually shorten by removing sarcomeres and setting a new baseline length. This is when true muscle shortening occurs and extensive stretching is required to correct the change. If your muscles are truly shortened, they will require much more work and time under tension to adapt and lay down new sarcomeres. Studies show that bouts of at least 30 second holds for stretches provide enough stimulus for adaptation3. In my experience, I have found that 3-5 sets of 30-60 second stretches work well.
Looking at the bigger picture, what is important for increasing and maintaining mobility and flexibility is posture and alignment. As mentioned above, the body initially tightens due to prolonged positions and imbalances. If we correct imbalances and improve posture, the body is able to relax and rely on its natural system of alignment without using extra muscular tone. Systems like Pilates are fantastic for improving posture and core engagement which facilitates alignment and mobility.
- Zöllner AM, Abilez OJ, Böl M, Kuhl E. Stretching Skeletal Muscle: Chronic Muscle Lengthening through Sarcomerogenesis. PLoS ONE 2012;7
- Guissard N, Duchateau J. Neural aspects of muscle stretching. Exerc Sport Sci Rev. 2006 Oct;34(4):154-8.
- Passive extensibility of skeletal muscle: review of the literature with clinical implications. Gajdosik RL. Clin Biomech (Bristol, Avon). 2001 Feb;16(2):87-101.