MAXIMUM ISOMETRIC FORCE PRODUCTION CHARACTERISTICS IN FIVE MUSCLE GROUPS IN YOUNG, MIDDLE-AGED AND OLDER MEN

1986 ◽  
Vol 18 (supplement) ◽  
pp. S7
Author(s):  
S. B. Going ◽  
B. H. Massey ◽  
T. C. Lohman ◽  
M. G. Bemben
1992 ◽  
Vol 4 (4) ◽  
pp. 537-545 ◽  
Author(s):  
C. B. Christ ◽  
R. A. Boileau ◽  
M. H. Slaughter ◽  
R. J. Stillman ◽  
J. A. Cameron ◽  
...  

2001 ◽  
Vol 281 (1) ◽  
pp. R155-R161 ◽  
Author(s):  
Timothy J. Koh ◽  
Susan V. Brooks

We tested the hypothesis that lengthening contractions and subsequent muscle fiber degeneration and/or regeneration are required to induce exercise-associated protection from lengthening contraction-induced muscle injury. Extensor digitorum longus muscles in anesthetized mice were exposed in situ to repeated lengthening contractions, isometric contractions, or passive stretches. Three days after lengthening contractions, maximum isometric force production was decreased by 55%, and muscle cross sections contained a significant percentage (18%) of injured fibers. Neither isometric contractions nor passive stretches induced a deficit in maximum isometric force or a significant number of injured fibers at 3 days. Two weeks after an initial bout of lengthening contractions, a second identical bout produced a force deficit (19%) and a percentage of injured fibers (5%) that was smaller than those for the initial bout. Isometric contractions and passive stretches also provided protection from lengthening contraction-induced injury 2 wk later (force deficits = 35 and 36%, percentage of injured fibers = 12 and 10%, respectively), although the protection was less than that provided by lengthening contractions. These data indicate that lengthening contractions and fiber degeneration and/or regeneration are not required to induce protection from lengthening contraction-induced injury.


2012 ◽  
Vol 513 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Dilip N. Athreya ◽  
Guy Van Orden ◽  
Michael A. Riley

2018 ◽  
Vol 43 (8) ◽  
pp. 816-821 ◽  
Author(s):  
David Bender ◽  
Jeremy R. Townsend ◽  
William C. Vantrease ◽  
Autumn C. Marshall ◽  
Ruth N. Henry ◽  
...  

The purpose of this study was to examine the effects of acute beetroot juice (BR) administration on repeated sprint performance and isometric force production in adolescent males. Twelve male adolescents (age, 16.8 ± 1.0 years; height, 178.8 ± 9.2 cm; mass, 74.8 ± 12.5 kg; peak height velocity, 2.53 ± 1.2 years) participated in this double-blind, placebo-controlled, crossover designed study. Participants consumed 2 × 70 mL of BR (∼12.9 mmol NO3−; Beet It Sport) or a nitrate-depleted placebo (PL) at 2.5 h prior to performing isometric mid-thigh pulls (IMTP) and 4 repeated 20-s Wingate sprints interspersed with 4 min of rest. Sprint data were analyzed by a 2 × 4 (group × time) repeated-measures ANOVA while a dependent t test was used to compare conditions for IMTP peak force. A significant main effect for time (p < 0.05) was observed for peak power (PP), average power (Pavg), and fatigue index (FI) across sprints. Compared with sprint 1, sprint 4 resulted in significant decreases in PP (p < 0.000; −16.6%) and Pavg (p = 0.000; −21.8%) and FI was significantly elevated (p < 0.000; 15.2%). No significant group × time interactions were observed between conditions for PP (p = 0.402), Pavg (p = 0.479), or FI (p = 0.37). IMTP peak force was significantly higher (p = 0.004; 13.9%) following BR consumption compared with PL. The repeated sprint protocol resulted in significant fatigue while BR did not influence sprint performance. However, it appears BR administration may improve peak force production in adolescent males.


2009 ◽  
Vol 35 (2) ◽  
pp. 439-446 ◽  
Author(s):  
Jacob J. Sosnoff ◽  
Andrew D. Valantine ◽  
Karl M. Newell

1990 ◽  
Vol 61 (4) ◽  
pp. 338-343
Author(s):  
Robert W. Christina ◽  
James H. Cauraugh ◽  
Aaron Shire

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