by Dolores G. Ortega, Robert W. Smith, Jocelyn E. Arnett, Tyler J. Neltner, Trevor D. Roberts, Richard J. Schmidt, Glen O. Johnson and Terry J. Housh
Original Research
The purpose of this study was to examine the effects of anchor scheme (RPE vs. torque) on the composite, inter- and intra-individual torque and neuromuscular patterns of responses (PoR) during fatiguing forearm flexion tasks. Twelve men (mean±SD: age=20.9±2.2 yrs.; height=179.8±5.3 cm; body mass=80.2±9.9 kg) performed maximal voluntary isometric contractions (MVIC) before and after sustained, isometric forearm flexion tasks to failure anchored to RPE=4 (RPEFT) and the torque (TRQFT) that corresponded to RPE=4. The amplitude (AMP) and mean power frequency (MPF) of the electromyographic and mechanomyographic (MMG) signals were recorded from the biceps brachii. Polynomial regression analyses were used to define the individual and composite relationships for normalized torque and neuromuscular parameters versus normalized time. Dependent t-tests were used to determine mean differences for time to task failure (TTF) and performance fatigability (PF=% decline in MVIC). The RPEFT had a greater TTF (p=0.006), but lower PF (p<0.001) than the TRQFT. During the RPEFT, the composite PoR indicated significant (p≤0.05) linear decreases for torque, EMG MPF, MMG MPF, and NME, a linear increase for MMG AMP, and no relationship for EMG AMP. During the TRQFT, the composite PoR indicated significant (p≤0.05) linear decreases for EMG MPF, MMG MPF, and NME, linear increases in EMG AMP and MMG AMP, and no relationship for torque. The individual PoR indicated substantial variability within and between anchor schemes. These findings indicated that TTF and PF as well as the composite, inter-, and intra-individual PoR were dependent on the anchor scheme of the fatiguing task.
American Journal of Sports Science and Medicine. 2024, 12(1), 7-19. DOI: 10.12691/ajssm-12-1-2
Pub. Date: March 01, 2024
by G.D. Fernandes and Victor Maldonado
Original Research
Negative splitting (i.e., finishing the race faster) is a tactic commonly employed by elite marathon athletes, even though research supporting the strategy is scarce. The presence of pacers allows the main runner to run behind a formation, preserving energy. Our aim is to show that, in the presence of pacers, the most efficient pacing strategy is positive splitting. We evaluated the performance of an elite marathon runner from an energetic standpoint, including drag values obtained through Computational Fluid Dynamics (CFD). In varying simulations for different pacing strategies, the energy for both the main runner and his pacer were conserved and the total race time was calculated. In order to achieve minimum race time, the main runner must start the race faster and run behind the pacers, and when the pacers drop out, finish the race slower. Optimal race times are obtained when the protected phase is run 2.4 to 2.6% faster than the unprotected phase. Our results provide strong evidence that positive splitting is indeed the best pacing strategy when at least one pacer is present, causing significant time savings in official marathon events.
American Journal of Sports Science and Medicine. 2024, 12(1), 1-6. DOI: 10.12691/ajssm-12-1-1
Pub. Date: February 02, 2024