Trisha A. McLain

Muscle activation of the quadriceps and hamstrings during incremental running

The aim of this study was to determine the patterns of responses for the electromyographic (EMG) amplitude vs. oxygen uptake ( V̇ O2) relationships from muscles of the quadriceps femoris and hamstrings during incremental treadmill running. Methods: Twelve men volunteered to perform an incremental test to exhaustion while EMG signals were recorded from the vastus lateralis, vastus medialis, biceps femoris, and semitendinosus muscles. Polynomial regression analyses were used to determine the best model fit for the EMG amplitude vs. V̇ O2 relationships. Results: There were significant (P < 0.05) increases in EMG amplitude across V̇ O2 for the vastus lateralis (quadratic, R = 0.995), vastus medialis (quadratic, R = 0.997), biceps femoris (cubic, R = 0.999), and semitendinosus (linear, R = 0.992) muscles as well as the hamstrings‐to‐quadriceps ratio (cubic, R = 0.999). Conclusion: These findings indicate that the patterns of responses for muscle activation vs. exercise intensity appear to be unique among muscles of the thigh. Muscle Nerve 52: 1023–1029, 2015

Development of an Anaerobic Sprint Running Test Using a Nonmotorized Treadmill.

Abstract McLain, TA, Wright, GA, Camic, CL, Kovacs, AJ, Hegge, JM, and Brice, GA. Development of an anaerobic sprint running test using a nonmotorized treadmill. J Strength Cond Res 29(8): 2197–2204, 2015—The purpose of this study was to determine the test-retest reliability of a newly developed anaerobic sprint running test (ASRT) on a nonmotorized treadmill (NMT). Twenty-six collegiate male athletes (21.2 ± 2.1 years; 181.3 ± 6.5 cm; 79.0 ± 9.3 kg) completed 3 trials of a 25-second maximal effort sprint on an NMT against a workload set to 18% of their individual body mass. Anaerobic power was determined by relative peak power output (PP) and anaerobic capacity was determined by relative mean power output (MP) during the test. Blood lactate (BLa) responses and fatigue index (FI) were also determined. Test-retest reliability was assessed by intraclass correlation coefficients (ICCs) and coefficients of variation (CV%). Results indicated no significant difference between the 3 trials for PP (T1 = 29.95 ± 6.51 W·kg−1, T2 = 28.57 ± 5.55 W·kg−1, T3 = 29.47 ± 5.94 W·kg−1), MP (T1 = 20.97 ± 3.64 W·kg−1, T2 = 20.50 ± 3.46 W·kg−1, T3 = 21.17 ± 3.79 W·kg−1), and FI (T1 = 55 ± 8%, T2 = 51 ± 8%, T3 = 52 ± 9%). Reliability between the 3 trials for PP (ICC: r = 0.96, CV: 7%) and MP (ICC: r = 0.97, CV: 6%) was considered high. Reliability for FI exhibited an ICC of r = 0.83 (CV: 6%). Postsprint BLa values were not significantly different (p = 0.49) between the 3 trials. Test-retest reliability for postsprint BLa was found to be good (r = 0.68, CV = 8.8%). The results of the study indicate that the ASRT is reliable for assessing PP and MP in highly motivated subjects. In addition, anaerobic testing using the ASRT may be a more sport-specific test to assess anaerobic performance for many coaches and athletes.

A comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and A-mode ultrasound to assess body composition in college-age adults.

There is currently a dearth of scientific literature exploring the agreement of A‐mode ultrasound (US) body composition analysis with dual‐energy X‐ray absorptiometry (DXA) and air displacement plethysmography (ADP). Objective: To investigate the agreement of US with DXA and ADP for estimating fat mass (FM) and fat‐free mass (FFM).