Neuromuskulär elektrisk stimulering sänder signaler för anabolism

[King Grub]

och sätter igång processer för hypertrofi, i synnerhet stimulering med hög frekvens.

Purpose

Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation settings to increase muscle mass and strength. However, the effects of NMES on muscle growth are not clear and no human studies have compared anabolic signaling between low-frequency (LF-) and high-frequency (HF-) NMES. The purpose of this study was to determine the skeletal muscle anabolic signaling response to an acute bout of LF- and HF-NMES.

Methods

Eleven young healthy volunteers (6 men; 5 women) received an acute bout of LF- (20 Hz) and HF- (60 Hz) NMES. Muscle biopsies were obtained from the vastus lateralis muscle prior to the first NMES treatment and 30-mins following each NMES treatment. Phosphorylation of the following key anabolic signaling proteins was measured by Western blot and proteins are expressed as a ratio of phosphorylated to total: mammalian target of rapamycin (mTOR), p70-S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E binding protein 1 (4E-BP1).

Results

Compared to Pre-NMES, phosphorylation of mTOR was upregulated 40.2% for LF-NMES (P = 0.018) and 68.4% for HF-NMES (P < 0.0001) and HF-NMES was 29.3% greater than LF-NMES (P = 0.026). Phosphorylation of S6K1 after HF-NMES was 96.6% higher than Pre-NMES (P = 0.001), was not different between Pre-NMES and LF-NMES (although was 50.4% higher after LF-) or LF- and HF-NMES (P > 0.05). There were no differences between treatment conditions for 4E-BP1 phosphorylation (P > 0.05).

Conclusion

An acute bout of LF- and HF-NMES upregulated anabolic signaling with HF-NMES producing a greater anabolic response compared to LF-NMES, suggesting that HF-stimulation may provide a stronger stimulus for processes that initiate muscle hypertrophy. Additionally, the stimulation frequency parameter should be considered by clinicians in the design of optimal NMES treatment protocols.

High-Frequency Neuromuscular Electrical Stimulation Increases Anabolic Signaling. Medicine & Science in Sports & Exercise: March 16, 2018.