Muscles and joints are frequently hurt when they are asked
to exceed their range of motion; resulting in tears, strains, dislocations etc.
Static stretching can improve flexibility, but depending on the activity,
rarely in sport are you asked to hold a muscle in a stretched position for an
extended period. Think of how the hamstrings are stretched when kicking a
football, the shoulders position during a throw or the hips when squatting;
it’s a dynamic movement.
While most associate increased strength with improved force
output, one of the main reasons resistance training improves an athlete’s
durability is due to the improvements in absorbing force. In short, stopping
unwanted movement.
Loaded stretching’s efficacy is due to improving both the
athlete’s ability to move with a full range of motion and to be strong in a full range of motion. Thus
when a joint is fully stretched and at its most vulnerable, the athlete is
strong enough to prevent it from going any further.
As for bigger muscles, according to the highly influential
research by Brad Shoenfeld; there are three factors to muscular growth:
muscular tension, muscle damage and metabolic stress (Schoenfeld, 2010). By
accentuating the eccentric portion of the exercise, more muscle damage is
achieved (in a positive way). Holding the stretched position for long periods
of time leads to occlusion of the muscle (starving it of oxygen temporarily,
leading to metabolic stress) and a significant amount of tension when loaded
appropriately.
How do I do it?
Easy, just hold an exercise at the end of your range of
motion where a stretch is placed on the muscle. For example, at the bottom of a
bench press. Note that dumbbells would be the superior option in order to sink
further into the stretch. An overhead squat is another example of loaded
stretching for the shoulder capsule, if someone is working on overhead
mobility.
Some exercises will work better than others; such as the
aforementioned dumbbell bench press over a barbell. Quads are tricky to
appropriately stretch; the quads flexibility during a squat movement is
unlikely to be the limiting factor and it is highly impractical to sufficiently
load the quads when stretched at both the knee and hip (imagine bringing your
foot back to your hips to stretch your quads, then pushing against your hand).
However, holding the bottom position of a lunge (with a long step) would be
sufficient for stretching the hips.
For how long?
Depends on your goal. For injury prevention / athletic
purposes, you’re training to resist having a muscle / joint being pushed that
bit too far when something does not go right; holding for extended periods is
not applicable. Holding 1-2 seconds after each rep, or 5-10 seconds at the end
of a set should be sufficient. For hypertrophy, the more metabolic stress you
can achieve the better. Holding for 30 seconds plus will have your muscles
screaming.
Suggestions for each muscle:
- Chest
- Bottom of a DB Chest Press
- Bottom of a DB Fly
- Shoulders
- Top of an overhead squat
- Bottom of a high incline press
- Biceps
- Bottom of a DB incline curl
- Triceps
- Bottom of a French press / skullcrusher
- Lats
- Bottom of a pull up or DB row
- Glutes
- Bottom of a long step lunge
- Quads
- Tricky. You could use a standing reach and push your foot into your hand / fixed object, but of all the major muscles this is the least practical to perform loaded stretching
- Hamstrings
- Bottom of a stiff legged deadlift
- Calves
- Bottom of a calf press
References:
Schoenfeld, B.J. (2014) The mechanisms of muscle hypertrophy
and their application to resistance training. Journal of Strength and Conditioning Research 24(10): 2857-2872