Any book that runs to seven editions over a period of 30 years must be doing something right. The first edition of this book appeared in 1985, and it seems remarkable that the two authors of that e...

Research methods in physical activity.

EMG amplitude, fatigue threshold, and time to task failure: A meta-analysis.

Centala, J, Pogorel, C, Pummill, SW, and Malek, MH. Listening to fast-tempo music delays the onset of neuromuscular fatigue. J Strength Cond Res 34(3): 617-622, 2020-Studies determining the effect of music on physical performance have primarily focused on outcomes such as running time to exhaustion, blood lactate, or maximal oxygen uptake. The electromyographic fatigue threshold (EMGFT) is determined through a single incremental test and operationally defined as the highest exercise intensity that can be sustained indefinitely without an increase in EMG activity of the working muscle. To date, no studies have examined the role of fast-tempo music on EMGFT. The purpose of this investigation, therefore, was to determine whether fast-tempo music attenuates neuromuscular fatigue as measured by the EMGFT. We hypothesized that listening to fast-tempo music during exercise would increase the estimated EMGFT compared with the control condition. Secondarily, we hypothesized that maximal power output would also increase as a result of listening to fast-tempo music during the exercise workbout. Ten healthy college-aged men (mean ± SEM: age, 25.3 ± 0.8 years [range from 22 to 31 years]; body mass, 78.3 ± 1.8 kg; height: 1.77 ± 0.02 m) visited the laboratory on 2 occasions separated by 7 days. The EMGFT was determined from an incremental single-leg knee-extensor ergometer for each visit. In a randomized order, subjects either listened to music or no music for the 2 visits. All music was presented as instrumentals and randomized with a tempo ranging between 137 and 160 b·min. The results indicated that listening to fast-tempo music during exercise increased maximal power output (No Music: 48 ± 4; Music: 54 ± 3 W; p = 0.02) and EMGFT (No Music: 27 ± 3; Music: 34 ± 4 W; p = 0.008). There were, however, no significant mean differences between the 2 conditions (no music vs. music) for absolute and relative end-exercise heart rate as well as end-exercise rating of perceived exertion for the exercised leg. These findings suggest that listening to fast-tempo music increased overall exercise tolerance as well as the neuromuscular fatigue threshold. The results are applicable to both sport and rehabilitative settings.

Listening to Fast-Tempo Music Delays the Onset of Neuromuscular Fatigue

Cognitive fatigue tasks performed before exercise may reduce exercise capacity. The electromyographic fatigue threshold (EMGFT) is the highest exercise intensity that can be maintained without significant increase in the electromyography (EMG) amplitude vs. time relationship. To date, no studies have examined the effect of cognitive fatigue on the estimation of the EMGFT. The purpose of this study, therefore, was to determine whether cognitive fatigue before performing exercise reduces the estimated EMGFT. Eight healthy college-aged men were recruited from a university student population and visited the laboratory on multiple occasions. In a randomized order, subjects performed either the cognitive fatigue task (AX continuous performance test) for 60 minutes on one visit (experimental condition) or watched a video on trains for 60 minutes on the other visit (control condition). After each condition, subjects performed the incremental single-leg knee-extensor ergometry test while the EMG amplitude was recorded from the rectus femoris muscle and heart rate was monitored throughout. Thereafter, the EMGFT was calculated for each subject for each visit and compared using paired samples t-test. For exercise outcomes, there were no significant mean differences for maximal power output between the 2 conditions (control: 51 +/- 5 vs. fatigue: 50 +/- 3 W), but there was a significant decrease in EMGFT between the 2 conditions (control: 31 +/- 3 vs. fatigue: 24 +/- 2 W; p = 0.013). Moreover, maximal heart rate was significantly different between the 2 conditions (control: 151 +/- 5 vs. fatigue: 132 +/- 6; p = 0.027). These results suggest that performing the cognitive fatiguing task reduces the EMGFT with a corresponding reduction in maximal heart rate response.

Reduced Electromyographic Fatigue Threshold After Performing a Cognitive Fatiguing Task.

Morse, JJ, Pallaska, G, Pierce, PR, Fields, TM, Galen, SS, and Malek, MH. Acute low-dose caffeine supplementation increases electromyographic fatigue threshold in healthy men. J Strength Cond Res 30(11): 3236-3241, 2016-The purpose of this study is to determine whether consumption of a single low-dose caffeine drink will delay the onset of the electromyographic fatigue threshold (EMGFT) in the superficial quadriceps femoris muscles. We hypothesize that the EMGFT values for the caffeine condition will be significantly higher than the EMGFT values for the placebo condition. On separate occasions, 10 physically active men performed incremental single-leg knee-extensor ergometry 1 hour after caffeine (200 mg) or placebo consumption. The EMGFT was determined for each participant for both conditions. The results indicated a significant increase for maximal power output (16%; p = 0.004) and EMGFT (45%; p = 0.004) in the caffeine condition compared with placebo. These findings suggest that acute low-dose caffeine supplementation delays neuromuscular fatigue in the quadriceps femoris muscles.

Acute Low-Dose Caffeine Supplementation Increases Electromyographic Fatigue Threshold in Healthy Men

INTRODUCTION The purpose of this study was to determine the intersession reliability of the electromyographic fatigue threshold (EMGFT ) for cycle ergometry. METHODS On separate occasions, 10 healthy, college-aged men performed an incremental test to voluntary exhaustion on a cycle ergometer. The EMG amplitude vs. time relationships for each power output from the quadriceps femoris muscles were analyzed using linear regression. EMGFT was defined operationally as the average of the highest power output that resulted in a non-significant slope coefficient (P >  0.05) and the lowest power output that resulted in a significant (P <  0.05) positive slope coefficient. The EMGFT values for trials 1 and 2 were used to calculate the intraclass correlation coefficient (ICC). RESULTS Overall, the reliability of the EMGFT (ICC2,1  = 0.85; 95% confidence interval 0.49-0.96) was in the "excellent" category. CONCLUSIONS The EMGFT for cycle ergometry is a reliable measure for assessing muscular fatigue.

Travis M. Buskirk

Papers

Test-retest reliability of the electromyographic fatigue threshold for cycle ergometry.