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1.
Previous studies that have examined self-efficacy-performance relationships have used novice performers. It is unclear if these findings would generalize to "experienced" performers. Based on Bandura's self-efficacy theory, this study was designed to investigate (a) the effects of false information feedback on self-efficacy beliefs and subsequent weightlifting performance, and (b) whether self-efficacy or past performance is most related to subsequent weightlifting performance. Experienced weightlifters engaged in six performance sessions, each consisting of a one-repetition-maximum bench press. Male subjects (N = 36) were randomly assigned to one of three treatment groups: accurate performance information, false information that they lifted more than their actual lift, or false information that they lifted less than their actual lift. Before each session, subjects indicated the amount of weight they were 100%, 75%, and 50% confident they could lift. Results replicated existing research findings regarding deception and performance; false positive feedback increased future bench press performance. In addition, results indicated that past weightlifting performance accounted for nearly all of the variance in subsequent performance. This finding is discussed in light of the difficulty in extending the predictions of self-efficacy theory to sport settings where athletes have gained experience by undergoing repeated training trials.  相似文献   

2.
The purpose of this study was to determine the association between weightlifting performance and vertical barbell acceleration patterns. Barbell kinematic time-series data were tracked from 18 snatches from six weightlifters during a regional weightlifting competition. These data were used to calculate vertical barbell accelerations. Time-series data were normalised to 100% of lift phase, defined as the time interval between barbell lift-off and maximum height of the barbell during each snatch lift. The time-series data were then entered into a pattern recognition algorithm that extracted principal patterns and calculated principal pattern scores. Body mass-normalised lift weight, which was used to quantify weightlifting performance, was significantly correlated (r = 0.673; P = 0.033) with a pattern that captured a difference in peak vertical barbell acceleration between the transition and the second pull phase. This correlation indicated that barbell acceleration profiles of higher weight snatch lifts were characterised by smaller decreases in acceleration during the second knee bend and smaller peak acceleration during the second pull phase. Weightlifting coaches and sports scientist should monitor and track vertical acceleration of the barbell, with focus on acceleration profiles that limit (1) deceleration during the transition phase between the first and second pull and (2) peak acceleration during the second pull phase of the snatch.  相似文献   

3.
Abstract

The present study compared the changes in markers of muscle damage after bouts of resistance exercise employing the Multiple-sets (MS) and Half-pyramid (HP) training systems. Ten healthy men (26.1±6.3 years), who had been involved in regular resistance training, performed MS and HP bouts, 14 days apart, in a randomised, counter-balanced manner. For the MS bout, participants performed three sets of maximum repetitions at 75%-1RM (i.e. 75% of a One Repetition Maximum) for the three exercises, starting with the bench press, followed by pec deck and decline bench press. For the HP bout, the participants performed three sets of maximum repetitions with 67%-1RM, 74%-1RM and 80%-1RM for the first, second and third sets, respectively, for the same three exercise sequences as the MS bout. The total volume of load lifted was equated between both bouts. Muscle soreness, plasma creatine kinase (CK) activity, myoglobin (Mb) and C-reactive protein (CRP) concentrations were assessed before and for three days after each exercise bout, and the changes over time were compared between MS and HP using two-way repeated measures ANOVA. Muscle soreness developed significantly (P<0.01) after both bouts, but no significant difference was observed between MS and HP. Plasma CK activity and Mb concentration increased significantly (P<0.01) without significant differences between bouts, and CRP concentration did not change significantly after either bout. These results suggest that the muscle damage profile is similar for MS and HP, probably due to the similar total volume of load lifted.  相似文献   

4.
Abstract

In this study, we compared the effectiveness of ratio and allometric scaling for normalizing power and strength in elite male rugby union players. Rugby union forwards (n = 18) and backs (n = 20) were assessed for squat jump and bench throw peak power, and box squat and bench press one-repetition maximum strength. The performance data for the forwards and backs were compared using ratio (P/BM) and allometric scaling (P/BMb ), where P represents performance, BM is body mass in kilograms, and b is a power exponent. A proposed allometric exponent (0.67) and exponents (±95% confidence intervals) derived for the box squat (0.33 ± 0.31), bench press (0.45 ± 0.30), bench throw (0.46 ± 0.36), and squat jump (0.64 ± 0.31) exercises were used. In general, the absolute expression of power and strength was superior for the heavier forwards, but after ratio scaling these performance measures then favoured the lighter backs. There were no performance differences between the forwards and backs after allometric scaling using either the proposed or the derived exponents. Thus, allometric scaling may provide a more effective method for normalizing power and strength in elite athletes when body size is a confounding variable.  相似文献   

5.
Abstract

The purpose of this study was to examine the relationships among mechanomyographic (MMG) amplitude, power output, and bar velocity during the free-weight bench press exercise. Twenty-one resistance-trained men [one-repetition maximum (1-RM) bench press = 125.4 ± 18.4 kg] performed bench press muscle actions as explosively as possible from 10% to 90% of the 1-RM while peak power output and peak bar velocity were assessed with a TENDO Weightlifting Analyzer. During each muscle action, surface MMG signals were detected from the right and left pectoralis major and triceps brachii, and the concentric portion of the range of motion was selected for analysis. Results indicated that power output increased from 10% to 50% 1-RM, followed by decreases from 50% to 90% 1-RM, but MMG amplitude for each of the muscles increased from 10 to 80%1-RM. The results of this study indicate that during the free-weight bench press exercise, MMG amplitude was not related to power output, but was inversely related to bar velocity and directly related to the external load being lifted. In future research, coaches and sport scientists may be able to estimate force/torque production from individual muscles during multi-joint, dynamic constant external resistance muscle actions.  相似文献   

6.
Abstract

The purpose of this study was to compare the effect on strength gains of two isoinertial resistance training (RT) programmes that only differed in actual concentric velocity: maximal (MaxV) vs. half-maximal (HalfV) velocity. Twenty participants were assigned to a MaxV (n = 9) or HalfV (n = 11) group and trained 3 times per week during 6 weeks using the bench press (BP). Repetition velocity was controlled using a linear velocity transducer. A complementary study (n = 10) aimed to analyse whether the acute metabolic (blood lactate and ammonia) and mechanical response (velocity loss) was different between the MaxV and HalfV protocols used. Both groups improved strength performance from pre- to post-training, but MaxV resulted in significantly greater gains than HalfV in all variables analysed: one-repetition maximum (1RM) strength (18.2 vs. 9.7%), velocity developed against all (20.8 vs. 10.0%), light (11.5 vs. 4.5%) and heavy (36.2 vs. 17.3%) loads common to pre- and post-tests. Light and heavy loads were identified with those moved faster or slower than 0.80 m·s?1 (～60% 1RM in BP). Lactate tended to be significantly higher for MaxV vs. HalfV, with no differences observed for ammonia which was within resting values. Both groups obtained the greatest improvements at the training velocities (≤0.80 m·s?1). Movement velocity can be considered a fundamental component of RT intensity, since, for a given %1RM, the velocity at which loads are lifted largely determines the resulting training effect. BP strength gains can be maximised when repetitions are performed at maximal intended velocity.  相似文献   

7.
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8.
ABSTRACT

The velocity and magnitude in which the eccentric phase of an exercise is completed directly affects performance during the concentric phase. Therefore, the purpose of this research was to investigate the effects of eccentric phase duration on concentric outcomes at 60% and 80% of one-repetition maximum (1RM) in the squat and bench press. Sixteen college-aged, resistance-trained males completed 1RM testing, established normative eccentric durations, and performed fast (0.75 times normative) and slow (2.0 times normative) metronome-controlled eccentric duration repetitions. Outcome measures assessed during the concentric phase were: average concentric velocity (ACV), peak concentric velocity (PCV), rating of perceived exertion (RPE), range of motion (ROM), and barbell path. Eccentric duration was significantly and inversely correlated with ACV at 60% (r = ?0.408, p = 0.004) and 80% (r = ?0.477, p = 0.001) of 1RM squat. At 60% of 1RM squat, both fast and slow eccentric conditions produced greater (p < 0.001) PCV than normative duration with fast also producing greater PCV than slow (p = 0.044). Eccentric duration had no impact on RPE, ROM, or barbell path. Our results report for the first time that resistance-trained males performing a deliberately faster eccentric phase may enhance their own squat and bench press performance.  相似文献   

9.
Abstract

Marked differences in the patterns of speed and accuracy of throwing were evident during a practice program characterized by different information feedback conditions for a sample of high school males. Analysis of subsequent performance scores via covariance procedures indicated an important role for information feedback. Improvement or reduction in performance was, in general, specific to the type and completeness of feedback provided and/or withheld during the practice program.  相似文献   

10.
The goal of this randomized, double-blind, cross-over study was to assess the acute effects of caffeine ingestion on muscular strength and power, muscular endurance, rate of perceived exertion (RPE), and pain perception (PP) in resistance-trained men. Seventeen volunteers (mean?±?SD: age?=?26?±?6 years, stature?=?182?±?9?cm, body mass?=?84?±?9?kg, resistance training experience?=?7?±?3 years) consumed placebo or 6?mg?kg?1 of anhydrous caffeine 1?h before testing. Muscular power was assessed with seated medicine ball throw and vertical jump exercises, muscular strength with one-repetition maximum (1RM) barbell back squat and bench press exercises, and muscular endurance with repetitions of back squat and bench press exercises (load corresponding to 60% of 1RM) to momentary muscular failure. RPE and PP were assessed immediately after the completion of the back squat and bench press exercises. Compared to placebo, caffeine intake enhanced 1RM back squat performance (+2.8%; effect size [ES]?=?0.19; p?=?.016), which was accompanied by a reduced RPE (+7%; ES?=?0.53; p?=?.037), and seated medicine ball throw performance (+4.3%, ES?=?0.32; p?=?.009). Improvements in 1RM bench press were not noted although there were significant (p?=?.029) decreases in PP related to this exercise when participants ingested caffeine. The results point to an acute benefit of caffeine intake in enhancing lower-body strength, likely due to a decrease in RPE; upper-, but not lower-body power; and no effects on muscular endurance, in resistance-trained men. Individuals competing in events in which strength and power are important performance-related factors may consider taking 6?mg?kg?1 of caffeine pre-training/competition for performance enhancement.  相似文献   

11.
Abstract

Muscular and aerobic capacity changes resulting from three months of wrestling training were examined in a group of normally active 7- to 9-year-old boys (N = 23) who competed in an intramural league tournament. A nontraining group of twenty-two boys of similar age, height, and weight served as control subjects, and were studied during the same period of time. The subjects were measured for body dimensions and skinfolds, and were given measures of back lift, leg press, and arm endurance (dips and chins). They were also measured for [Vdot]E max, [Vdot]O 2 max, and HR max employing a progressive treadmill protocol. Results of ANCOVA analyses indicated that (1) the mean improvements in [Vdot]E max (2.93 1·min ?1 ) and in [Vdot]O 2 max (+ 6.6 ml·kg ?1 ·min ?1 ) were not significantly greater than control (p > .05), nor was HR max; (2) arm endurance improved significantly over control (p < .05), as did the leg press, but the back lift was not improved significantly (p > .05); (3) no significant change occurred in height, weight, or in some of skinfolds (p > .05), but the wrestlers were less endomorphic and more ectomorphic than their control counterparts, and were judged essentially equivalent in mesomorphy. It is concluded that wrestling training in young boys improves strength, but does not improve aerobic capacity more than one would expect to see in normal children of similar age and size.  相似文献   

12.
Understanding how loading affects power production in resistance training is a key step in identifying the most optimal way of training muscular power – an essential trait in most sporting movements. Twelve elite male sailors with extensive strength-training experience participated in a comparison of kinematics and kinetics from the upper body musculature, with upper body push (bench press) and pull (bench pull) movements performed across loads of 10–100% of one repetition maximum (1RM). 1RM strength and force were shown to be greater in the bench press, while velocity and power outputs were greater for the bench pull across the range of loads. While power output was at a similar level for the two movements at a low load (10% 1RM), significantly greater power outputs were observed for the bench pull in comparison to the bench press with increased load. Power output (P max) was maximized at higher relative loads for both mean and peak power in the bench pull (78.6 ± 5.7% and 70.4 ± 5.4% of 1RM) compared to the bench press (53.3 ± 1.7% and 49.7 ± 4.4% of 1RM). Findings can most likely be attributed to differences in muscle architecture, which may have training implications for these muscles.  相似文献   

13.
Abstract

We examined the performance and organizational stressors encountered by elite and non-elite athletes within the competition environment. Twelve sport performers (6 elite, 6 non-elite) were interviewed about both performance and organizational-related demands experienced when preparing for competition. The framework presented identifies five performance (i.e. preparation, injury, expectations, self-presentation, and rivalry) and five organizational (i.e. factors intrinsic to the sport, roles in the sport organization, sport relationships and interpersonal demands, athletic career and performance development issues, and organizational structure and climate of the sport) stress sources. A similar quantity of performance (#PS) and organizational (#OS) stressors were encountered by elite performers (#PS = 127; #OS = 72) as by non-elite athletes (#PS = 123; #OS = 74), with some demands being common and others unique to each group. Although the findings suggest that, prior to competing, sport performers encounter more stressors pertinent to performance than those emanating from the organization, these observations highlight that all the demands faced by athletes should be considered when preparing and implementing interventions to manage competition stress.  相似文献   

14.
Abstract

The efficacy of caffeine ingestion in enhancing aerobic performance is well established. However, despite suggestions that caffeine may enhance resistance exercise performance, research is equivocal on the effect of acute caffeine ingestion on resistance exercise performance. It has also been suggested that dampened perception of perceived exertion and pain perception might be an explanation for any possible enhancement of resistance exercise performance due to caffeine ingestion. Therefore, the aim of this study was to examine the acute effect of caffeine ingestion on repetitions to failure, rating of perceived exertion (RPE) and muscle pain perception during resistance exercise to failure. Eleven resistance trained individuals (9 males, 2 females, mean age±SD=26.4±6.4 years), took part in this double-blind, randomised cross-over experimental study whereby they ingested a caffeinated (5 mg kg?1) or placebo solution 60 minutes before completing a bout of resistance exercise. Experimental conditions were separated by at least 48 hours. Resistance exercise sessions consisted of bench press, deadlift, prone row and back squat exercise to failure at an intensity of 60% 1 repetition maximum. Results indicated that participants completed significantly greater repetitions to failure, irrespective of exercise, in the presence of caffeine (p=0.0001). Mean±S.D of repetitions to failure was 19.6±3.7 and 18.5±4.1 in caffeine and placebo conditions, respectively. There were no differences in peak heart rate or peak blood lactate values across conditions (both p >0.05). RPE was significantly lower in the caffeine compared to the placebo condition (p=0.03) and was significantly higher during lower body exercises compared to upper body exercises irrespective of substance ingested (p=0.0001). For muscle pain perception, a significant condition by exercise interaction (p=0.027) revealed that muscle pain perception was lower in the caffeine condition, irrespective of exercise. With caffeine, pain perception was significantly higher in the deadlift and back squat compared to the bench press. However, with placebo, pain perception was significantly higher for the deadlift and back squat compared to the prone row only. Therefore, acute caffeine ingestion not only enhances resistance exercise performance to failure but also reduces perception of exertion and muscle pain.  相似文献   

15.
Abstract

The aims of this study were to determine if the primary time constant (τ) for oxygen uptake ([Vdot]O2) at the onset of moderate-intensity treadmill exercise is related to endurance running performance, and to establish if τ could be considered a determinant of endurance running performance. Thirty-six endurance trained male runners performed a series of laboratory tests, on separate days, to determine maximal oxygen uptake ([Vdot]O2max), the ventilatory threshold (VT) and running economy. In addition, runners completed six transitions from walking (4 km · h?1) to moderate-intensity running (80% VT) for the determination of the [Vdot]O2 primary time constant and mean response time. During all tests, pulmonary gas-exchange was measured breath-by-breath. Endurance running performance was determined using a treadmill 5-km time-trial, after which runners were considered as combined performers (n=36) and, using a ranking system, high performers (n=10) and low performers (n=10). Relationships between τ and endurance running performance were quantified using correlation coefficients (r). Stepwise multiple regression was used to determine the primary predictor variables of endurance running performance in combined performers. Moderate correlations were observed between τ, mean response time and endurance running performance, but only for the combined performers (r=?0.55, P=0.001 and r=?0.50, P=0.002, respectively). The regression model for predicting 5-km performance did not include τ or mean response time. The velocity at [Vdot]O2max was strongly correlated to endurance running performance in all groups (r=0.72 – 0.84, P < 0.01) and contributed substantially to the prediction of performance. In conclusion, the results suggest that despite their role in determining the oxygen deficit and having a moderate relationship with endurance running performance, neither τ nor mean response time is a primary determinant of endurance running performance.  相似文献   

16.
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17.

Purpose: The relationships among students' self-efficacy, 2 × 2 achievement goals (mastery-approach [MAp], mastery-avoidance [MAv], performance-approach [PAp], and performance-avoidance goals), and achievement performance remain largely unanswered. We tested a model of the mediating role of self-efficacy on the relationship between 2 × 2 achievement goals and cardiorespiratory fitness. Method: A sample of 276 middle school students (115 boys and 161 girls; 91 sixth graders, 87 seventh graders, and 98 eighth graders), aged 12 to 15 years (M age = 13.34, SD = 0.96), responded to the Achievement Goals Questionnaire (Conroy, Elliot, &; Hofer, 2003) and Self-Efficacy Questionnaire (Gao, Newton, &; Carson, 2008) referenced to the fitness test. Their cardiorespiratory fitness was assessed via the Progressive Aerobic Cardiorespiratory Endurance Run (PACER) 3 days later. Results: Structural equation modeling demonstrated an acceptable model fit to the data, χ 2 (2, N = 105) = 1.66. Self-efficacy had a statistically significant direct effect on the PACER after controlling for the effects of the achievement goals (γ self-efficacy-PACER  = .21). MAv and PAp also had direct effects on PACER performance (γ MAv-PACER  = ? .24, and γ PAp-PACER  = .24, respectively). MAp failed to exert direct effect on the PACER. However, the indirect effect of MAp on the PACER via self-efficacy was small although it was statistically significant. Additionally, the indirect effects of MAv and PAp on PACER through self-efficacy were not significant. Conclusions: Students' self-efficacy fully mediated the effect of MAp on fitness performance, as well as partially mediated the effects of MAv and PAp on cardiorespiratory fitness performance. Study implications are provided for educators and practitioners.  相似文献   

18.
Abstract

The purpose of this study was to examine the relationships between decision-making self-efficacy and task self-efficacy and subsequent decision-making and task performance. Sixty undergraduate students (30 males, 30 females) participated in this study, which involved infield defensive plays in softball. The physical task required participants to throw a ball at a target. The decision-making task required participants to watch video scenes depicting different infield defensive situations and decide where to throw the ball in each situation. Both tasks used manipulated failure. Self-efficacy was assessed before performance. Strength of decision-making and task self-efficacy predicted physical performance, but not decision-making performance.  相似文献   

19.
Prestigious professional organisations have questioned the efficacy of resistive training by children or have often neglected to address weightlifting in their position papers on resistive training for children. The purpose of this paper was to address the deficit in data regarding the efficacy of training children for weightlifting and to report data regarding to safety in this population. Eleven subjects (3 female, 8 male) who had trained at the USA Weightlifting Development Centre in Shreveport Louisiana for a minimum of 22 months (mean = 28.8; SD +/- 4.4) served as subjects for this study. Means for the pool of subjects subjected to t-test to compare data obtained at each subject's initial competition with that obtained at the individual's most recent competition revealed significant positive changes in body weight, snatch weight, clean and jerk weight, and total weight lifted. The latter three were significant both in absolute weight and in weight lifted per kg of body weight. Total weight lifted at competitions plotted separately for boys and for girls across time indicated an apparently steeper slope of improvement for boys. The latter were not tested for significance because of the small sample sizes. The lack of injury in training and in 534 competitive lifts was discussed. None required medical attention or loss of training time. It was concluded that there can be no doubt regarding the efficacy of weightlifting as carried out at the USA Weightlifting Development Centre. The importance of proper application of scientific theory of conditioning in a conservative manner for this population was emphasised.  相似文献   

20.
Abstract

The aim of the study was to examine the sticking region and concomitant neuromuscular activation of the prime movers during six-repetition maximum (RM) bench pressing. We hypothesised that both peak velocities would decrease and that the electromyography (EMG) of the prime movers (deltoid, major pectoralis and triceps) would increase during the pre-sticking and sticking region during the six repetitions due to fatigue. Thirteen resistance-trained males (age 22.8 ± 2.2 years, stature 1.82 ± 0.06 m, body mass 83.4 ± 7.6 kg) performed 6-RM bench presses. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, and triceps brachii during the pre-, sticking and post-sticking region of each repetition in a 6-RM bench press were analysed. For both the sticking as the post-sticking region, the time increased significantly from the first to the sixth repetition. Vertical barbell height at the start of sticking region was lower, while the height at the end of the sticking region and post-sticking region did not change during the six repetitions. It was concluded that in 6-RM bench pressing performance, the sticking region is a poor mechanical force region due to the unchanged barbell height at the end of the sticking region. Furthermore, when fatigue occurs, the pectoralis and the deltoid muscles are responsible for surpassing the sticking region as indicated by their increased activity during the pre- and sticking region during the six-repetitions bench press.  相似文献   

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