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Jules Mitchell
MS in exercise science (biomechanics), California State University Long Beach · author of Yoga Biomechanics: Stretching Redefined
Go-to expert for: the science of stretching
Who and why
Jules Mitchell is a yoga teacher, educator and massage therapist with a master's degree in exercise science focused on biomechanics. Her book, Yoga Biomechanics: Stretching Redefined, uses research from sport science and rehabilitation to explain what stretching does and does not do. She teaches stretching science and research literacy to yoga teachers worldwide and is a former adjunct faculty member at Arizona State University.
Why it matters after 50: Many older adults stretch to feel less stiff. Knowing what stretching actually changes helps you choose sensible goals and combine it with strength work for joints that move well and feel safe.
What Mitchell recommends
- Feeling tight is a sensation, not a measure of how long a muscle is. Much of the range you gain from regular stretching comes from your nervous system getting used to the stretch.Some evidence
- Think of stretching as one way of loading your tissues. Muscles, tendons and connective tissue adapt to the loads you give them over time.Note
- Strength matters as much as flexibility. Hard muscle work loads tendons more than passive stretching, which is why strengthening is the usual approach for irritated tendons.Some evidence
- Fit the pose to your body, not your body to the pose. Use props and vary positions instead of forcing a standard shape.Personal habit
- If a tendon is irritated, gentler stretching that backs off from the end of your range may be enough. She notes this has not been tested directly.Note
Signature: Yoga Biomechanics: Stretching Redefined
Her book shifts the focus from flexibility itself to how body tissues adapt to load. It examines common yoga and stretching beliefs through biomechanics research and frames pose changes as a way of managing load.
In your plan
Choose her for mobility: stretching treated like training, built up gradually week by week.
Research and honest caveats
Stretching changes sensation more than length
A review found that gains in range after single sessions and 3- to 8-week stretching programmes are mostly explained by changes in sensation rather than longer muscles.
Weppler & Magnusson, Physical Therapy, 2010
Four weeks of daily hamstring stretching
Stretching 20 minutes each weekday raised tolerance to stretch but did not make the hamstrings more extensible.
Folpp et al., Australian Journal of Physiotherapy, 2006
- She is an educator who interprets research rather than a lead scientist on stretching trials, and the studies above are by other researchers. Long-term effects of stretching (beyond about 8 weeks) on the tissues themselves are still not well studied.
Career highlights
- 2015Profiled while finishing her master's thesis on the science of stretching (CSU Long Beach)
- 2018–19Published Yoga Biomechanics: Stretching Redefined (Handspring Publishing)