Why do you stretch?

Now let us just explore: Why do you want / need to be flexible?
Are you trying to prevent injuries?
Sorry to tell you, but there is only inconsequential (high quality) scientific proof that static stretching or PNF stretching does that! I’ll discuss dynamic stretching a little later.
 Yoga not for you, because, you are not flexible?
Yoga teachers usually are flexible! But more important: if they are not strong, their flexibility actually can be a risk for injuries!
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​So how come you are (not) flexible? Is it functional or it is a lack of enough movement?
Sometimes having short muscles can be functional and beneficial, for example if you are a soccer player. While kicking a ball, the knee has to extend quick and short hamstrings will help to slow down the movement and help to reduce the stress on passive structures knee capsule, crucial and collateral ligaments.
Or cyclist and ice skaters (speed): they have limited range of motion of the hip flexor (M. ilipsoas), because they need to be strong in a shortened position: “sitting” deep on the ice or bike and lifting the leg in a small range of motion pulling the pedal up on the bike.
Most people stretch because they think it is important to be flexible. Only when you have specific “functions” in mind, longer muscles might make sense.
And then trying to stretch to lengthen might not be the solution. Different studies show that stretching does not alter tissues quick, only when stretching is performed a lot over a long time. And then the changes will be more through neurological adaptations then tissue lengthening.
 
So, what is the solution if you want longer muscles? 
Strengthen, not just lengthen!
Train muscles eccentric in an elongated state. 
Eccentric training causes sarcomerogenisis (O'Sullivan et al. (2012): This means that the muscle creates new sarcomeres (image 1) in the muscle, leading to a longer and stronger muscle in an elongated state.

Dynamic stretching is similar to a form of lengthen the muscle and strengthen (static or dynamic) and does come close to training eccentric in an elongated state.
 
What does this eccentric training look like? For example, for the hamstrings it can be done by Romanian deadlift and also with Nordic curls.
 
Romanian deadlift:
Lower 3-5 seconds’ eccentric and move quick concentric
You might know this move from body pump classes or doing them at the gym.

Squat and stoop technique
And if you are a builder this is functional (even though the advice is to bend the knees while lifting, called squad technique), there is also the stoop technique that has equal load on the lower back and guess what? By the way does that looks like the Romanian deadlift? According to Timmins et al. (2016) this may be achieved in 14 days of 3 sessions per week. (More research is needed though).

And yes: Aussie health and safety regulations does only advice squat, but the stoop technique happens to show that the load is almost equal on Lumbar spine disc L4/5. Depending on the task and I guess the mobility of the person!
 
Conclusion: Strengthen eccentric in elongated state to lengthen!
With weight training, in yoga or at work!
 
Want to find out what works for you or not?
Call 0415442029 for a consultation/private yoga lesson
 
 
​References:

Behm DG,  Blazevich AJ, AD Kay (2016) Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review
- Applied physiology …, 2015 - NRC Research Press

Dreischarf, M Rohlmann, A et al (2016) In vivo loads on a vertebral body replacement during different lifting techniques Journal of Biomechanics
Volume 49, Issue 6, 11 April 2016, Pages 890-895

Konrad et al. (2014): https://www.ncbi.nlm.nih.gov/pubmed/24856792

Freitas et al. (2015): https://www.ncbi.nlm.nih.gov/pubmed/25486299

Weppler et al. (2010): https://www.ncbi.nlm.nih.gov/pubmed/20075147

O'Sullivan et al. (2012):https://www.ncbi.nlm.nih.gov/pubmed/22522590

Timmins et al. (2016): https://www.ncbi.nlm.nih.gov/pubmed/26460634