Chronic Adaptations To Resistance Training Of Soleus H-reflex

Previous studies have shown that 3-4 weeks of training (strength, endurance, ballistic, and even sensorimotor) have not shown a significant increase or decrease in the soleus H-reflex. However, chronic effects of lifting weights might have different results. PURPOSE: Therefore, this study analyzes H-reflex amplitude from students that have been consistently lifting weights for 12 months or more. METHODS: Seven healthy young adults (M ± SD 23 ± 4.1 yrs.) answered a health questioner which included an activity portion where the amount of time spent weightlifting per week was recorded. The tibial nerve was stimulated, and soleus activity was recorded while participants stood shoulder width apart looking straight forward. We started with the M-wave recruitment curve with an intensity at 5 mA and increasing by 5 mA every 8-10 seconds until the max was reached (Mmax). To ensure the stimulus strength remained relatively constant for all participants, an intensity was used that elicited a M-wave of 15% of Mmax. At this intensity we evoked 10 H-reflexes, averaged, and normalized to Mmax (H-reflex; %Mmax). A Pearson correlation was run to identify the relationship between minutes per week lifting weights and H-reflex; alpha set at 0.05. RESULTS: Preliminary findings show there is a strong negative relationship (r = -0.65) between time lifting weights per week and H-reflex; however, it was not significant. (p = 0.1) CONCLUSIONS: Despite previous research suggesting that a few weeks of training does not significantly alter the soleus reflex, our preliminary results indicate a trend where more time spent lifting weights each week is associated with a lower reflex size.