Skin application of menthol enhances maximal isometric lifting performance

Topical application of menthol to the skin improves perception (i.e., makes subjects feel cooler) and changes sub-maximal neuromuscular recruitment facilitating force generation. We explored the effect of menthol (0.2% concentration; sprayed on the legs), on perception and maximal, dynamic (DLT) and isometric (IMLT) [weight] lifting tasks. Nine resistance trained males (mean ± SD: 24 ± 5 years; 75.7 ± 8.8 kg; 174 ± 10 cm; 5 repetition maximum deadlift [5RM] 132.3 ± 28.5 kg) were tested using a repeated measures design; we hypothesized performance would improve. Prior to completing the DLT (i.e., deadlift performance 75% 1RM) and a mid-thigh pull dynamometer IMLT, subjects were sprayed with (~125 mL) of Menthol or Control-Spray. Performance, electromyography (root mean squared rmsEMG; rectus femoris[RF], biceps femoris[BF], medial gastrocnemius[MG]), perceptions (Leg thermal sensation[TSlegs] and comfort[TClegs], perceived exertion [RPE] and readiness to train), heart rate and skin temperature were measured. Data were compared using ANOVA (effect size ηp²) and t-test to 0.05 alpha level supported by Bayesian analysis. DLT performance was unchanged although BF rmsEMG was higher (i.e., greater muscle activation in final [10th] repetition). IMLT force production was higher in the Menthol-Spray (148 ± 30 kgf) condition (Control-Spray 140 ± 30 kgf; p = .035, ηp² = .444) with corresponding higher rmsEMG (BF 3.8 ± 1.46 vs. Control-Spray 2.9 ± 0.34 v; p = .049, ηp² = .403). TSlegs was lower after Menthol-Spray prior to IMLT; subjects felt slightly cool. Menthol-Spray enhances isometric weightlifting performance with corresponding changes in neuromuscular activity; partially supporting our hypothesis