Stretching, Mobility and the Confused

Stretching and warming up are essential to preventing injury, increasing and creating balance throughout the body. But there is a difference between the two.
A lot of misinformed fitness professionals and coaches static stretch their clients and athletes before strength training, endurance, sport, ect. They do this in order to “warm up the muscles”.

The problem is that static stretching does not warm-up the muscles and should not be done pre-training. It has been seen to interfere with proper nerve function causing loss of strength and proprioception (sense of self in space), decreasing performance and actually increasing risk of injury.

When Should Stretching Be Done Then?

Static stretching should only be done to muscles that are overly tight and need to be stretched. Being hyperflexible is only slighty less dangerous than being hypoflexible. In other words, do not stretch muscles that do not  feel tight or a joint that has full range of motion. Static stretching is best done when the muscles are warmed up (post exercise, body temperature over 109) and/or right before bed, so that when your body repairs at night, it repairs the muscles to their ideal range of motion (ROM).

What is the ideal or average Range of Motion?

Normal Values for Range of Motion of Joints according to Merck Manual
Joint Motion Range (°)
Hip Flexion 0–125
Extension 115–0
Hyperextension† 0–15
Abduction 0–45
Adduction 45–0
Lateral rotation 0–45
Medial rotation 0–45
Knee Flexion 0–130
Extension 120–0
Ankle Plantar flexion 0–50
Dorsiflexion 0–20
Foot Inversion 0–35
Eversion 0–25
Metatarsophalangeal joints Flexion 0–30
Extension 0–80
Interphalangeal joints of toes Flexion 0–50
Extension 50–0
Shoulder Flexion to 90° 0–90
Extension 0–50
Abduction to 90° 0–90
Adduction 90–0
Lateral rotation 0–90
Medial rotation 0–90
Elbow Flexion 0–160
Extension 145–0
Pronation 0–90
Supination 0–90
Wrist Flexion 0–90
Extension 0–70
Abduction 0–25
Adduction 0–65
Metacarpophalangeal joints Abduction 0–25
Adduction 20–0
Flexion 0–90
Extension 0–30
Interphalangeal proximal joints of fingers Flexion 0–120
Extension 120–0
Interphalangeal distal joints of fingers Flexion 0–80
Extension 80–0
Metacarpophalangeal joint of thumb Abduction 0–50
Adduction 40–0
Flexion 0–70
Extension 60–0
Interphalangeal joint of thumb Flexion 0–90
Extension 90–0

*A goniometer would be ideal for measuring joint angles, but visual estimates are just as good to me.

Lastly, it must be understood that static stretching is not the only way to increase joint flexibility. Strength training is also a great way to build flexibility in the joints from neurological demands and actual tissue manipulation.