Stretching is a commonly used method thought to improve muscle length. Contrary to belief, there is a lack of studies correlating stretching with improved muscle length.
Moreover, stretching lacks the research behind many of its glorious claims (injury prevention, sports performance, etc.). In fact, a couple of studies indicate being more flexible is an injury risk.
This purpose of this investigation was conducted to determine the acute effect of passive static stretching of the lower-body musculature on lower-body strength in a one repetition maximum (1RM) squat exercise in young (18 – 24 years) moderately trained men.
What was done
Two different warm-ups were used prior to the strength testing on nonconsecutive days. The first warm-up consisted of an active dynamic warm-up (AD) with variable resistance training machines and free weights. The second warm-up added passive static stretching (PSS) of the lower-body musculature before the AD warm-up. The PSS consisted of three sets of 10-second stretches for the quadriceps, hamstring, calf, abdominal and lower-back musculature.
Following the warm-up, each subject performed multiple trials of the squat exercise following a progressive resistance protocol until the 1RM was determined.
Paired t-tests revealed a significant decrease in both 1RM squat (8.36%) and lower-body stability/balance (22.68%) following PSS.
This study confirms other findings, suggesting PSS directly following a strength exercise decreases performance. This is potentially secondary to impairment on the muscle-tendon unit (MTU). The idea is the decrease in force production is a result of slack in the tendon following stretching; resulting in less force production.
Neuromuscular alterations may also explain the decrease in performance, as reflex sensitivity may decrease following PSS.
This study suggests it would be unwise to perform PSS directly before a maximal power exercise. Combine this study with finding other research and it appears that swimmers should not perform PSS directly before their race.
- Gergley JC. Rotational Med Ball Slam Acute Effect of Passive Static Stretching on Lower-
body Strength in Moderately Trained Males. J Strength Cond Res. 2012 Jun 11. [Epub ahead of print]
Originally Posted July 2012