Does Strength Training Reduce Flexibility?
AFS Education
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Does resistance training reduce flexibility? Should you always stretch after lifting to prevent muscles from shortening? Do bigger muscles reduce one’s flexibility? These are some of the most common questions/concerns new clients have when starting a program involving resistance training. How much should you be concerned about your flexibility when you start a resistance training program?
The answer to all of these questions is an emphatic NO! In fact, resistance training when performed through a full range of motion actually IMPROVES flexibility! This may be hard to believe if you typically are “tight” a day or two after training; this “tightness”, however, is an acute transient effect due to muscle damage. Consistent resistance training through a full range of motion actually improves flexibility.
Research
A recent study comparing static stretching and strength training found the following:
· Stretching and strength training increased hamstring flexibility to the same degree.
· Resistance training outperformed static stretching at improving hip flexibility.
· Resistance training improved strength around all joints while stretching did not.
How?
During strength training, there is a lifting and lowering phase. It is the lowering phase (think of lowering a dumbbell down on a bicep curl) where the flexibility benefit of strength training is derived. During this lowering (or “eccentric”) phase, new muscle fibers can actually be laid down “in series” with one another. This means that the muscle is actually structurally lengthened by doing exercises that emphasize a controlled lowering phase through full ranges of motion. Now, with that said, if you only work through small ranges of motion, you obviously will not benefit from any of these benefits in flexibility. Additionally, if you already have mobility deficits in certain areas of your body (your shoulders for example) doing certain exercises may exacerbate that deficit. This is why it is so important to have some knowledgeable guidance when undergoing a strength training program.
Conclusion
Contrary to common gym lore, resistance training does not reduce flexibility. When an exercise is performed properly, through a full range of motion, it will actually help increase your flexibility. For individuals looking to significantly improve flexibility, a combination of resistance training and static stretching would optimize results.