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Purpose <p>To compare the effects of 6&#xa0;weeks of combined high- and low-load lower body resistance training (H + L) to high-load only training (H) on maximal strength, muscle thickness (MT), and electromyographic (EMG<sub>RMS</sub>)–torque relationships of the vastus lateralis during an absolute muscular endurance (AME) task. </p> Methods <p>Twenty-eight untrained males performed maximal voluntary contractions (MVCs) and trapezoidal muscle actions to failure at the same absolute 50% MVC for the knee extensors before (PRE) and after training (POST<sub>ABS</sub>). Individual <i>b</i>- and <i>a</i>-terms were calculated from the log-transformed EMG<sub>RMS</sub>–torque relationships during the linearly increasing (LI) and decreasing (LD) segments of the first (FMA) and last muscle action (LMA). The <i>b-</i>terms examine the rate of change in EMG<sub>RMS</sub> in relation to torque and the <i>a-</i>terms reflect an upward/downward shifting of the overall relationship without changing EMG<sub>RMS</sub> linearity. Steady torque EMG<sub>RMS</sub> was normalized (N-EMG<sub>RMS</sub>).</p> Results <p>After training: maximal strength increased similarly between the groups (<i>p</i> &lt; 0.001). MT increased for both groups (<i>p</i> &lt; 0.001–0.01), but was greater for H + L (<i>p</i> &lt; 0.022). Only H + L improved AME (<i>p</i> &lt; 0.001). The <i>b</i>-terms decreased, whereas the <i>a</i>-terms increased for both groups during the FMA LD and LMA LI (<i>p</i> &lt; 0.001–0.030). N-EMG<sub>RMS</sub> for H + L decreased across muscle actions (<i>p</i> &lt; 0.001).</p> Conclusion <p>Despite similar increases in strength, only H + L improved AME, exhibited greater hypertrophy, and required less muscle excitation at steady torque. The changes in <i>b</i>- and <i>a</i>-terms suggest reduced muscle excitation was necessary to match torque during the upper regions of FMA LD and LMA LI. Therefore, H + L training may improve strength and endurance, and reduce neural cost during sustained activities.</p>

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The influence of high-load and combined high- and low-load resistance training on electromyographic behavior during an absolute muscular endurance task

  • 期刊论文

  • 发表日期：

    2025年6月24日

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  • Alex A. Olmos,
  • Stephanie A. Sontag,
  • Daniel J. Lawson,
  • Lyric D. Richardson,
  • Brenden L. Roth,
  • Sunggun Jeon,
  • Jaiden C. Smith,
  • Allen L. Redinger,
  • Michael A. Trevino

摘要

Purpose

To compare the effects of 6 weeks of combined high- and low-load lower body resistance training (H + L) to high-load only training (H) on maximal strength, muscle thickness (MT), and electromyographic (EMGRMS)–torque relationships of the vastus lateralis during an absolute muscular endurance (AME) task.

Methods

Twenty-eight untrained males performed maximal voluntary contractions (MVCs) and trapezoidal muscle actions to failure at the same absolute 50% MVC for the knee extensors before (PRE) and after training (POSTABS). Individual b- and a-terms were calculated from the log-transformed EMGRMS–torque relationships during the linearly increasing (LI) and decreasing (LD) segments of the first (FMA) and last muscle action (LMA). The b-terms examine the rate of change in EMGRMS in relation to torque and the a-terms reflect an upward/downward shifting of the overall relationship without changing EMGRMS linearity. Steady torque EMGRMS was normalized (N-EMGRMS).

Results

After training: maximal strength increased similarly between the groups (p < 0.001). MT increased for both groups (p < 0.001–0.01), but was greater for H + L (p < 0.022). Only H + L improved AME (p < 0.001). The b-terms decreased, whereas the a-terms increased for both groups during the FMA LD and LMA LI (p < 0.001–0.030). N-EMGRMS for H + L decreased across muscle actions (p < 0.001).

Conclusion

Despite similar increases in strength, only H + L improved AME, exhibited greater hypertrophy, and required less muscle excitation at steady torque. The changes in b- and a-terms suggest reduced muscle excitation was necessary to match torque during the upper regions of FMA LD and LMA LI. Therefore, H + L training may improve strength and endurance, and reduce neural cost during sustained activities.