Power-Time, Force-Time, and Velocity-Time Curve Analysis during the Jump Squat: Impact of Load

2008 ◽  
Vol 24 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Prue Cormie ◽  
Jeffrey M. McBride ◽  
Grant O. McCaulley
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Peak Power ◽  
Peak Power Output ◽  
Power Development ◽  
Time Curve ◽  
Force Time ◽  
The Impact ◽  
External Loads ◽  
Male Subjects

The purpose of this investigation was to examine the impact of load on the power-, force- and velocity-time curves during the jump squat. The analysis of these curves for the entire movement at a sampling frequency of 200–500 Hz averaged across 18 untrained male subjects is the most novel aspect of this study. Jump squat performance was assessed in a randomized fashion across five different external loads: 0, 20, 40, 60, and 80 kg (equivalent to 0 ± 0, 18 ± 4, 37 ± 8, 55 ± 12, 74 ± 15% of 1RM, respectively). The 0-kg loading condition (i.e., body mass only) was the load that maximized peak power output, displaying a significantly (p≤ .05) greater value than the 40, 60, and 80 kg loads. The shape of the force-, power-, and velocity-time curves changed significantly as the load applied to the jump squat increased. There was a significantly greater rate of power development in the 0 kg load in comparison with all other loads examined. As the first comprehensive illustration of how the entire power-, force-, and velocity-time curves change across various loading conditions, this study provides extensive evidence that a load equaling an individuals body mass (i.e., external load = 0 kg) maximizes power output in untrained individuals during the jump squat.

Reducing Anxiety and Anxiety Sensitivity With High-Intensity Interval Training in Adults With Asthma

2020 ◽  
Vol 17 (8) ◽  
pp. 835-839
Author(s):  
Carley O’Neill ◽  
Shilpa Dogra
Keyword(s):  
Anxiety Sensitivity ◽  
Power Output ◽  
High Intensity ◽  
Peak Power ◽  
Interval Training ◽  
Peak Power Output ◽  
Sensitivity Index ◽  
High Intensity Interval Training ◽  
High Intensity Interval ◽  
The Impact

Background: Low- and moderate-intensity exercise training has been shown to be effective for reducing general anxiety and anxiety sensitivity among adults with asthma. Exercise frequency and intensity have been shown to play an integral role in reducing anxiety sensitivity; however, less is known about the impact of high-intensity interval training (HIIT) on anxiety in adults with asthma. Methods: A 6-week HIIT intervention was conducted with adults with asthma. Participants completed HIIT (10% peak power output for 1 min, 90% peak power output for 1 min, repeated 10 times) 3 times per week on a cycle ergometer. Preintervention and postintervention assessments included the Anxiety Sensitivity Index-3 and the Body Sensations Questionnaire. Results: Total Anxiety Sensitivity Index-3 (PRE: 17.9 [11.8]; POST 12.4 [13], P = .002, Cohen d = 0.4, n = 20) and Body Sensations Questionnaire (PRE: 2.4 [1.0]; POST: 2.0 [0.8], P = .007, Cohen d = 0.3) improved from preintervention to postintervention. Conclusion: A 6-week HIIT intervention leads to improved anxiety among adults with asthma. Future research should determine the impact of HIIT among adults with asthma with clinical anxiety.

scholarly journals Determining the Peak Power Output for Weightlifting Derivatives Using Body Mass Percentage: A Practical Approach

2021 ◽  
Vol 3 ◽  
Author(s):  
Marcel Lopes dos Santos ◽  
Adam Jagodinsky ◽  
Kristen M. Lagally ◽  
Valmor Tricoli ◽  
Ricardo Berton
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Peak Power ◽  
Practical Approach ◽  
Peak Power Output ◽  
Mass Percentage

scholarly journals Preexercise Cycling Protocol Alters Pacing Behavior in Competitive Time Trials

2020 ◽  
Vol 15 (9) ◽  
pp. 1303-1308
Author(s):  
Marco J. Konings ◽  
Florentina J. Hettinga
Keyword(s):  
Power Output ◽  
Repeated Measures ◽  
Peak Power ◽  
Perceived Exertion ◽  
Time Trial ◽  
Cycle Ergometer ◽  
Peak Power Output ◽  
Experimental Conditions ◽  
And Performance ◽  
The Impact

Purpose: The behavior of an opponent has been shown to alter pacing and performance. To advance our understanding of the impact of perceptual stimuli such as an opponent on pacing and performance, this study examined the effect of a preexercise cycling protocol on exercise regulation with and without an opponent. Methods: Twelve trained cyclists performed 4 experimental, self-paced 4-km time-trial conditions on an advanced cycle ergometer in a randomized, counterbalanced order. Participants started the time trial in rested state (RS) or performed a 10-min cycling protocol at 67% peak power output (CP) before the time trial. During the time trials, participants had to ride alone (NO) or against a virtual opponent (OP). The experimental conditions were (1) RS-NO, (2) RS-OP, (3) CP-NO, and (4) CP-OP. Repeated-measures analyses of variance (P < .05) were used to examine differences in pacing and performance in terms of power output. Results: A faster pace was adopted in the first kilometer during RS-OP (318 [72] W) compared with RS-NO (291 [81] W; P = .03), leading to an improved finishing time during RS-OP compared with RS-NO (P = .046). No differences in either pacing or performance were found between CP-NO and CP-OP. Conclusions: The evoked response by the opponent to adopt a faster initial pace in the 4-km time trial disappeared when cyclists had to perform a preceding cycling protocol. The outcomes of this study highlight that perceived exertion alters the responsiveness to perceptual stimuli of cyclists during competition.

CYP1A2 Genotype Polymorphism Influences the Effect of Caffeine on Anaerobic Performance in Trained Males

2021 ◽  
pp. 1-6
Author(s):  
Shahin Minaei ◽  
Morteza Jourkesh ◽  
Richard B. Kreider ◽  
Scott C. Forbes ◽  
Tacito P. Souza-Junior ◽  
...  
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Peak Power ◽  
Anaerobic Power ◽  
Random Order ◽  
Peak Power Output ◽  
Fatigue Index ◽  
Double Blind ◽  
Minimum Power ◽  
Output Only

The purpose was to investigate the effects of CYP1A2 −163C > A polymorphism on the effects of acute caffeine (CAF) supplementation on anaerobic power in trained males. Sixteen trained males (age: 21.6 ± 7.1 years; height: 179.7 ± 5.6 cm; body mass: 72.15 ± 6.8 kg) participated in a randomized, double-blind, placebo (PLA) controlled crossover design. Participants supplemented with CAF (6 mg/kg of body mass) and an isovolumetric PLA (maltodextrin) in random order and separated by 7 days, before an all-out 30-s anaerobic cycling test to determine peak, average, and minimum power output, and fatigue index. Genomic deoxyribonucleic acid was extracted to identify each participants CYP1A2 genotype. Six participants expressed AA homozygote and 10 expressed C alleles. There was a treatment by genotype interaction for peak power output (p = .041, η2 = .265, observed power = 0.552) with only those expressing AA genotype showing improvement following CAF supplementation compared with PLA (CAF: 693 ± 108 watts vs. PLA: 655 ± 97 watts; p = .039), while no difference between treatments was noted in those expressing C alleles (CAF: 614 ± 92 watts vs. PLA: 659 ± 144 watts; p = .135). There were no other interaction or main effects for average or minimum power output, or fatigue index (p > .05). In conclusion, the ingestion of 6 mg/kg of CAF improved peak power output only in participants with the AA genotype compared with PLA; however, expression of the CYP1A2 did not influence average or minimum power output or fatigue index.

The effect of load based on body mass percentage on peak power output in the hang power clean, hang high pull, and mid-thigh clean pull

2021 ◽  
Author(s):  
Marcel LOPES DOS SANTOS ◽  
Ricardo BERTON ◽  
Adam E. JAGODINSKY ◽  
Michael R. TORRY ◽  
Kristen M. LAGALLY
Keyword(s):  
Body Mass ◽  
Power Output ◽  
Peak Power ◽  
Peak Power Output ◽  
Mass Percentage ◽  
Power Clean

The Influence of Recovery Duration on High-Intensity Exercise Performance After Oral Creatine Supplementation

1997 ◽  
Vol 22 (5) ◽  
pp. 454-467 ◽  
Author(s):  
William H. Cooke ◽  
William S. Barnes
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Peak Power ◽  
Creatine Supplementation ◽  
Cycle Ergometer ◽  
Peak Power Output ◽  
Significant Group ◽  
Before And After ◽  
Maximal Peak ◽  
Male Subjects

The purpose of this study was to determine the effects of creatine supplementation on the ability to reproduce and maintain a high percentage of peak power output during the second of two bouts of high-intensity cycle sprinting following four different recovery intervals. Eighty healthy, active male subjects were randomly assigned to one of two groups (creatine or placebo) and one of four recovery intervals (30, 60, 90, or 120 s). Two maximal cycle ergometer sprints, separated by the assigned recovery interval were performed before and after a 5-day supplementation protocol in which 20 g/day of creatine (plus 4 g/day glucose) or 24 g/day glucose placebo were ingested by subjects from creatine and placebo groups, respectively. Maximal peak power output (PP) and the absolute time to fatigue (TTF) were compared pre- versus postsupplementation. No significant group interactions were noted in this study. Specifically, creatine supplementation had no effect on subjects' ability to reproduce or maintain a high percentage of PP during the second bout of exercise. Key words: ergogenic aids, cycle ergometry, short-term fatigue

scholarly journals Physiological and perceptual responses to training and competition in elite female netball players

2021 ◽  
Author(s):  
◽  
Laurence Birdsey
Keyword(s):  
Strength Training ◽  
Power Output ◽  
Peak Power ◽  
Peak Velocity ◽  
Training Session ◽  
Peak Power Output ◽  
Jump Height ◽  
Match Play ◽  
Neuromuscular Performance ◽  
The Impact

Few studies have reported the physical demands of, and physiological responses to, training and competition in international netball players. This thesis set out to investigate this in female players via a series of studies. Study one characterised the playing demands of international match-play, and the physiological and perceptual responses to an international netball tournament. Mid-court performed at a higher Player LoadTM (mean difference ± standard deviation: 85.7% ± 49.6%), and internal intensity (mean heart rate: 3.7% ± 3.8%) than goal-based positions. Neuromuscular performance decreased after a single match (jump height: 4.0% ± 2.5%) whilst markers of muscle damage, soreness and perceived fatigue accumulated across the tournament. Study two characterised the physiological and perceptual responses to a regularly performed netball-training session. Neuromuscular performance was enhanced immediately post-exercise (Cohen’s d effect size, percent change: peak power output: 0.47, 5%), returned to baseline two hours post, and was reduced 24 h post-training (peak power output: 0.27, 3%; jump height: 0.39, 6%). Study three investigated the effect of training-session order. Performing netball prior to strength training resulted in enhanced neuromuscular performance two hours post-training (peak power output: 1.2, 5%; jump height: 1.2, 9%; peak velocity: 1.0, 3%), whilst strength followed by netball reduced neuromuscular performance at 20 h post (peak power output: 1.1, 4%; jump height: 1.4, 10%; peak velocity: 1.4, 4%). This thesis provides a detailed investigation in to the responses to netball training and competition, as well as the impact of training-session order on neuromuscular, perceptual and endocrine responses over 20 h. Training should be individualised to condition players for the positional-specific external and internal demands of international match-play. To optimise training performance, two hours post-training could be a more favourable time to perform explosive training than the following day, whilst technical netball training should precede strength training when both sessions are performed within the same training day.

scholarly journals Peak Power Output in the Bench Pull Is Maximized After Four Weeks of Specific Power Training

2016 ◽  
Vol 30 (4) ◽  
pp. 966-972
Author(s):  
Russell I. Jolley ◽  
Jon E. Goodwin ◽  
Daniel J. Cleather
Keyword(s):  
Power Output ◽  
Peak Power ◽  
Peak Power Output ◽  
Specific Power ◽  
Power Training

Abstract P134: Preliminary Data: Dietary Nitrate Supplementation Does Not Extend Dry Static Apnea Or Wingate Performance

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Colin Carriker ◽  
Phillip Armentrout ◽  
Sarah Levine ◽  
James Smoliga
Keyword(s):  
Power Output ◽  
Preliminary Data ◽  
Repeated Measures ◽  
Peak Power ◽  
Hold Time ◽  
Wingate Test ◽  
Peak Power Output ◽  
Breath Hold ◽  
Dietary Nitrate ◽  
Nitrate Supplementation

Introduction: Previous studies have examined dietary nitrate supplementation and its effects on dry static apnea, and peak power. Dietary nitrate supplementation has been found to increase maximal apnea and peak power output. The purpose of this study was to determine the effects of beetroot juice on dry static apnea and Wingate performance. Hypothesis: Dietary nitrate will improve maximal breath hold time and peak power output. Dietary nitrate will improve tolerance to CO2, thereby improving maximal breath hold time and anaerobic capacity. Methods: In a randomized, double-blind, counterbalanced study, five healthy males (20.4±0.89 years) visited the lab on 3 separate occasions each separated by one week. Visit 1 served as a Wingate and breath hold familiarization visit. Prior to visits 2 and 3 participants were instructed to drink a beverage either a placebo (negligible nitrate content, PL) or dietary nitrate rich beverage (12.4 mmol nitrate, NIT) during the 4 days leading up to their next visit. Visits 2 and 3 consisted of two submaximal breath holds (80% of maximal determined during visit 1), with 2 minutes of rest between and three minutes of rest preceding the final breath hold for maximal duration. Finally, participants completed a standardized 10-minute warmup on the cycle ergometer before completing a 30-second maximal effort Wingate test. Results: A linear mixed effects model was used to determine whether treatment (NIT vs. PL) was associated with differences in VCO2 or PetCO2. Time (0, 10, 20, 30 min post-breath hold) and Treatment both served as repeated measures. Models were developed using multiple repeated measures covariance matrix structures, and the model with the lowest AIC was chosen as the final model. The interaction between time and treatment was included in the original models, and was removed if it was not statistically significant. Time was a statistically significant factor for VCO2 and PetCO2 (p < 0.001). Treatment, and the Time x Treatment interaction was not significant for either variable. No differences between NIT and PL were observed during the Wingate test for either time to peak power (5.02±2.45 and 6.2±2.43 sec, respectively) or maximal power (9.73±1.01 and 9.72±1.03 watts/kg, respectively) and fatigue index (49.42±14.98 and 47.30±6.99 watts/sec, respectively). Conclusion: Preliminary data indicates that in a general population four days of dietary nitrate supplementation may not improve breath hold time, tolerance to carbon dioxide in the lungs, or Wingate performance.

Force-velocity and force-power properties of single muscle fibers from elite master runners and sedentary men

1996 ◽  
Vol 271 (2) ◽  
pp. C676-C683 ◽  
Author(s):  
J. J. Widrick ◽  
S. W. Trappe ◽  
D. L. Costill ◽  
R. H. Fitts
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Power Output ◽  
Peak Power ◽  
Isometric Force ◽  
Peak Force ◽  
Peak Power Output ◽  
Type I ◽  
Shortening Velocity ◽  
Force Velocity

Gastrocnemius muscle fiber bundles were obtained by needle biopsy from five middle-aged sedentary men (SED group) and six age-matched endurance-trained master runners (RUN group). A single chemically permeabilized fiber segment was mounted between a force transducer and a position motor, subjected to a series of isotonic contractions at maximal Ca2+ activation (15 degrees C), and subsequently run on a 5% polyacrylamide gel to determine myosin heavy chain composition. The Hill equation was fit to the data obtained for each individual fiber (r2 > or = 0.98). For the SED group, fiber force-velocity parameters varied (P < 0.05) with fiber myosin heavy chain expression as follows: peak force, no differences: peak tension (force/fiber cross-sectional area), type IIx > type IIa > type I; maximal shortening velocity (Vmax, defined as y-intercept of force-velocity relationship), type IIx = type IIa > type I; a/Pzero (where a is a constant with dimensions of force and Pzero is peak isometric force), type IIx > type IIa > type I. Consequently, type IIx fibers produced twice as much peak power as type IIa fibers, whereas type IIa fibers produced about five times more peak power than type I fibers. RUN type I and IIa fibers were smaller in diameter and produced less peak force than SED type I and IIa fibers. The absolute peak power output of RUN type I and IIa fibers was 13 and 27% less, respectively, than peak power of similarly typed SED fibers. However, type I and IIa Vmax and a/Pzero were not different between the SED and RUN groups, and RUN type I and IIa power deficits disappeared after power was normalized for differences in fiber diameter. Thus the reduced absolute peak power output of the type I and IIa fibers from the master runners was a result of the smaller diameter of these fibers and a corresponding reduction in their peak isometric force production. This impairment in absolute peak power production at the single fiber level may be in part responsible for the reduced in vivo power output previously observed for endurance-trained athletes.

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