scholarly journals Isometric force production before and after chemical skinning in isolated muscle fibres of the frog Rana temporaria.

1989 ◽  
Vol 410 (1) ◽  
pp. 171-185 ◽  
Author(s):  
G Elzinga ◽  
G J Stienen ◽  
M G Wilson
Keyword(s):  
Rana Temporaria ◽  
Isometric Force ◽  
Force Production ◽  
Muscle Fibres ◽  
Before And After ◽  
Frog Rana Temporaria ◽  
Isometric Force Production

Feedback about isometric force production yields more random variations

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

Postactivation Potentiation of Force Is Independent of H-Reflex Excitability

2008 ◽  
Vol 3 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Matthew J. Hodgson ◽  
David Docherty ◽  
E. Paul Zehr
Keyword(s):  
Isometric Force ◽  
Plantar Flexion ◽  
Force Production ◽  
H Reflex ◽  
Postactivation Potentiation ◽  
Neural Excitability ◽  
Reflex Excitability ◽  
Before And After ◽  
History Of ◽  
A Minor

The contractile history of muscle can potentiate electrically evoked force production. A link to voluntary force production, related in part to an increase in reflex excitability, has been suggested.Purpose:Our purpose was to quantify the effect of postactivation potentiation on voluntary force production and spinal H-reflex excitability during explosive plantar fexion actions.Methods:Plantar flexor twitch torque, soleus H-reflex amplitudes, and the rate of force development of explosive plantar fexion were measured before and after 4 separate conditioning trials (3 × 5 s maximal contractions).Results:Twitch torque and rate of force production during voluntary explosive plantar flexion were significantly increased (P < .05) while H-reflex amplitudes remained unchanged. Although twitch torque was significantly higher after conditioning, leading to a small increase in the rate of voluntary force production, this was unrelated to changes in reflex excitability.Conclusion:We conclude that postactivation potentiation may result in a minor increase in the rate of voluntary isometric force production that is unrelated to neural excitability.

Acute beetroot juice administration improves peak isometric force production in adolescent males

2018 ◽  
Vol 43 (8) ◽  
pp. 816-821 ◽  
Author(s):  
David Bender ◽  
Jeremy R. Townsend ◽  
William C. Vantrease ◽  
Autumn C. Marshall ◽  
Ruth N. Henry ◽  
...  
Keyword(s):  
Isometric Force ◽  
Force Production ◽  
Sprint Performance ◽  
Peak Force ◽  
Adolescent Males ◽  
Height Velocity ◽  
Beetroot Juice ◽  
Repeated Sprint ◽  
Group Time ◽  
Isometric Force Production

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.

The energetic cost of activation of white muscle fibres from the dogfish Scyliorhinus canicula

1997 ◽  
Vol 200 (3) ◽  
pp. 495-501 ◽  
Author(s):  
F Lou ◽  
N Curtin ◽  
R Woledge
Keyword(s):  
Heat Production ◽  
White Muscle ◽  
Isometric Force ◽  
Force Production ◽  
Total Heat ◽  
Energetic Cost ◽  
Maximum Efficiency ◽  
Muscle Fibres ◽  
Scyliorhinus Canicula ◽  
A Value

The energetic cost of activation was measured during an isometric tetanus of white muscle fibres from the dogfish Scyliorhinus canicula. The total heat production by the fibres was taken as a measure of the total energetic cost. This energy consists of two parts. One is due to crossbridge interaction which produces isometric force, and this part varies linearly with the degree of filament overlap in the fibres. The other part of the energy is that associated with activation of the crossbridges by Ca2+, mainly with uptake of Ca2+ into the sarcoplasmic reticulum by the ATP-driven Ca2+ pump. Total heat production was measured at various degrees of filament overlap beyond the optimum for force development. Extrapolation of heat versus force production data to evaluate the heat remaining at zero force gave a value of 34&plusmn;5 % (mean &plusmn; s.e.m., N=24) for activation heat as a percentage of total heat production in a 2.0 s isometric tetanus. Values for 0.4 and 1.0 s of stimulation were similar. Comparison with values in the literature shows that the energetic cost of activation in dogfish muscle is very similar to that of frog skeletal muscle and it cannot explain the lower maximum efficiency of dogfish muscle compared with frog muscle. The proportion of energy for activation (Ca2+ turnover) is similar to that expected from a simple model in which Ca2+ turnover was varied to minimize the total energy cost for a contraction plus relaxation cycle.

The adaptive range of 1/f isometric force production.

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

Time Needed to Change the Isometric Force Production of a Response

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