Preheated muscles respond better to light strength training
If, due to a serious injury or illness, you are unable to do strength training as it should be done, but you can still train with light weights, then there might be a way to increase the muscle-strengthening impact of your light workout. According to a Japanese human study, which appeared in BMC Musculoskeletal Disorders, a 20-minute exposure to heat makes muscles more sensitive to the growth stimulus of light strength training.
The researchers divided 30 healthy men into 2 equally large groups. During the 6 weeks that their experiment took, the researchers got the men to train their triceps 3 times a week with the lying triceps dumbbell extension. The men made 3 sets of 8 reps with 30 percent of the weight with which they could just make 1 rep.
Besides training, the experimental group received heat treatment before the men trained their triceps. This meant that the researchers wrapped the men's triceps for 20 minutes with a towel and a heat pad pre-heated to 75 degrees Celsius. As a result, the temperature in the triceps increased from 34 degrees to 37 degrees Celsius.
According to previously published studies, a short-term heat treatment in the muscles activates the protein HSP72. HSP72 is a heat shock protein that protects muscle cells against the negative effects of heat stress. It seems that HSP72 triggers anabolic processes. For example, it stimulates the manufacture of IGF-1 and activitates anabolic signaling molecules like mTOR and Akt in muscle cells.
The combination of light strength training and heat resulted in more muscle strength and more muscle size than light strength training alone.
BMC Musculoskelet Disord. 2019;20(1):603.
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