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Bibliografia sobre Supino

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Electromyographic activity of the pectoralis major and anterior deltoid muscles during three upper-body lifts.

Welsch EA, Bird M, Mayhew JL.

Exercise Science Program, Truman State University, Kirksville, Missouri 63501, USA. elizabethwelsch@hotmail.com

The purpose of this study was to examine the differences in activation levels and times of activation for the pectoralis major and anterior deltoid when performing the concentric phase of 3 upper-body lifts. Twelve college-age men and women with various degrees of lifting experience performed 3 repetitions using the 6 repetition maximum in a barbell bench press, dumbbell bench press, and dumbbell fly while being monitored for electromyographic activity in both muscles. Motor unit activation of both muscles was not significantly different during all 3 lifts. However, dumbbell flys had significantly less relative time of activation than did barbell or dumbbell bench presses. Therefore, dumbbell flys may be better suited as an auxiliary lift, whereas barbell and dumbbell bench presses may be used interchangeably in training programs. The compatibility of the barbell and dumbbell bench presses may aid lifters in overcoming training plateaus by alternating exercises for the same muscle groups.

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PMID: 15903389 [PubMed - indexed for MEDLINE]


 
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No difference in 1RM strength and muscle activation during the barbell chest press on a stable and unstable surface.

Goodman CA, Pearce AJ, Nicholes CJ, Gatt BM, Fairweather IH.

Centre for Ageing, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, Melbourne, Australia. goodmanc@unimelb.edu.au

Exercise or Swiss balls are increasingly being used with conventional resistance exercises. There is little evidence supporting the efficacy of this approach compared to traditional resistance training on a stable surface. Previous studies have shown that force output may be reduced with no change in muscle electromyography (EMG) activity while others have shown increased muscle EMG activity when performing resistance exercises on an unstable surface. This study compared 1RM strength, and upper body and trunk muscle EMG activity during the barbell chest press exercise on a stable (flat bench) and unstable surface (exercise ball). After familiarization, 13 subjects underwent testing for 1RM strength for the barbell chest press on both a stable bench and an exercise ball, each separated by at least 7 days. Surface EMG was recorded for 5 upper body muscles and one trunk muscle from which average root mean square of the muscle activity was calculated for the whole 1RM lift and the concentric and eccentric phases. Elbow angle during each lift was recorded to examine any range-of-motion differences between the two surfaces. The results show that there was no difference in 1RM strength or muscle EMG activity for the stable and unstable surfaces. In addition, there was no difference in elbow range-of-motion between the two surfaces. Taken together, these results indicate that there is no reduction in 1RM strength or any differences in muscle EMG activity for the barbell chest press exercise on an unstable exercise ball when compared to a stable flat surface. Moreover, these results do not support the notion that resistance exercises performed on an exercise ball are more efficacious than traditional stable exercises.

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PMID: 18296960 [PubMed - indexed for MEDLINE]


 
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Fatigue effects on bar kinematics during the bench press.

Duffey MJ, Challis JH.

Biomechanics Laboratory, University Park, The Pennsylavania Stae University, Pennsylvania 16802, USA.

The bench press is one of the most popular weight training exercises. Although most training regimens incorporate multiple repetition sets, there are few data describing how the kinematics of a lift change during a set to failure. To examine these changes, recreational lifters (10 men and 8 women) were recruited. The maximum weight each subject could bench press (1RM) was determined. Subjects then performed as many repetitions as possible at 75% of the 1RM load. Three-dimensional kinematic data were recorded and analyzed for all lifts. Statistical analysis revealed that differences between maximal and submaximal lifts and the kinematics of a submaximal lift change as a subject approaches failure in a set. The time to lift the bar more than doubled from the first to the last repetition, causing a decrease in both mean and peak upward velocity. Furthermore, the peak upward velocity occurred much earlier in the lift phase in these later repetitions. The path the bar followed also changed, with subjects keeping the bar more directly over the shoulder during the lift. In general, most of the kinematic variables analyzed became more similar to those of the maximal lift as the subjects progressed through the set, but there was considerable variation between subjects as to which repetition was most like the maximal lift. This study shows that there are definite changes in the lifting kinematics in recreational lifters during a set to failure and suggests it may be particularly important for coaches and less-skilled lifters to focus on developing the proper bar path, rather than reaching momentary muscular failure, in the early part of a training program.

PMID: 17530967 [PubMed - indexed for MEDLINE]

 
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Effects of increased eccentric loading on bench press 1RM.

Doan BK, Newton RU, Marsit JL, Triplett-McBride NT, Koziris LP, Fry AC, Kraemer WJ.

The Biomechanics Laboratory, Ball State University, Muncie, Indiana 47306, USA. bkdoan@bsuvc.bsu.edu

The purpose of this study was to measure the effects of additional eccentric loading on subsequent concentric strength. Eight subjects with some experience in weight training volunteered to perform maximal attempts in the barbell bench press using detaching hooks that allowed them to lower 105% of their concentric 1 repetition maximum (RM) and raise 100%. The detaching hooks allowed attachment of extra weight to the bar and would release from the bar at the bottom of the lift, reducing the weight lifted during the concentric phase of the lift. After determining their 1RM for the bench press, the subjects attempted to increase their performance by using a heavier eccentric load with the detaching hooks. All 8 subjects who completed the study increased their 1RMs by 5 to 15 pounds. The use of additional eccentric loading significantly (p = 0.008) increased the weight that could be lifted on the subsequent concentric phase and therefore 1RM performance. This phenomenon was a result of the enhancement of stretch-shortening cycle performance by the increased eccentric load. Athletes who are interested in developing 1RM strength in the bench press may benefit from the use of additional eccentric loading.

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PMID: 11834100 [PubMed - indexed for MEDLINE]


 
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Validation of an optical encoder during free weight resistance movements and analysis of bench press sticking point power during fatigue.

Drinkwater EJ, Galna B, McKenna MJ, Hunt PH, Pyne DB.

School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia. edrinkwater@csu.edu.au

During the concentric movement of the bench press, there is an initial high-power push after chest contact, immediately followed by a characteristic area of low power, the so-called "sticking region." During high-intensity lifting, a decline in power can result in a failed lift attempt. The purpose of this study was to determine the validity of an optical encoder to measure power and then employ this device to determine power changes during the initial acceleration and sticking region during fatiguing repeated bench press training. Twelve subjects performed a free weight bench press, a Smith Machine back squat, and a Smith Machine 40-kg bench press throw for power validation measures. All barbell movements were simultaneously monitored using cinematography and an optical encoder. Eccentric and concentric mean and peak power were calculated using time and position data derived from each method. Validity of power measures between the video (criterion) and optical encoder scores were evaluated by standard error of the estimate (SEE) and coefficient of variation (CV). Seven subjects then performed 4 sets of 6 free weight bench press repetitions progressively increasing from 85 to 95% of their 6 repetition maximum, with each repetition continually monitored by an optical encoder. The SEE for power ranged from 3.6 to 14.4 W (CV, 1.0-3.0%; correlation, 0.97-1.00). During the free weight bench press training, peak power declined by approximately 55% (p < 0.01) during the initial acceleration phase of the final 2 repetitions of the final set. Although decreases in power of the sticking point were significant (p < 0.01), as early as repetition 5 (-40%) they reached critically low levels in the final 2 repetitions (>-95%). In conclusion, the optical encoder provided valid measures of kinetics during free weight resistance training movements. The decline in power during the initial acceleration phase appears a factor in a failed lift attempt at the sticking point.

Publication Types:


PMID: 17530976 [PubMed - indexed for MEDLINE]


 
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The influence of grip width and forearm pronation/supination on upper-body myoelectric activity during the flat bench press.

Lehman GJ.

Department of Graduate Studies and Research, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada. glehman@cmcc.ca

The myoelectric signal of the sternoclavicular and clavicular portions of the pectoralis major, the biceps brachii, and the lateral head of triceps brachii of 12 healthy men was collected during an isometric hold of 5 different bench press exercises. Grip width (narrow, mid, and wide) and the level of supination/pronation was varied to determine how these factors influence myoelectric amplitude during the flat bench press. A supinated grip resulted in increased activity for the biceps brachii and the clavicular portion of the pectoralis major. Additionally, moving from wide to narrower grip widths increased triceps activity and decreased the sternoclavicular portion of the pectoralis major. However, if the grip was supinated, moving to a narrower grip position did not result in a decrease in muscle activity of the sternoclavicular portion of the pectoralis major. The increase in triceps brachii activity when moving to a narrower grip width was not influenced by the level of supination. Considering the small changes that occur during changes in grip width, the choice of grip position should be determined by the positions athletes adopt during their sport. Sport specificity should supercede attempts to train specific muscle groups.

PMID: 16095407 [PubMed - indexed for MEDLINE]

 
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Efficacy of instability resistance training.

Cowley PM, Swensen T, Sforzo GA.

Department of Exercise and Sport Sciences, Ithaca College, Ithaca, USA. pmcowley@syr.edu

The use of the stability ball as a platform for upper-body resistance training has gained much attention in recent years. However, the efficacy of such training regimens remains largely unstudied. The purpose of this study was to evaluate the influence of platform (unstable vs. stable, stability ball vs. flat bench) on strength and work capacity during barbell chest-press exercise. We also sought to determine the effects of a barbell chest-press training program performed on a stability ball or flat bench on strength, work capacity, and abdominal power. Fourteen young women (20 - 23 yr) performed a 1 repetition maximum (1RM) barbell chest-press and the YMCA bench press test (YBT) on a stability ball and flat bench, as well as two field tests measuring abdominal power. The women were then assigned to perform 3 weeks of barbell chest-press training on a stability ball (SB group) or flat bench (FB group); assignment was balanced based on 1RM strength. Barbell chest-press training included 3 sets of 3 - 5 repetitions at loads greater or equal to 85 % of 1RM. The 1RM barbell chest-press, YBT, front abdominal power test (FAPT), and side abdominal power test (SAPT) were used to evaluate changes in strength, work capacity, and abdominal power, respectively. The chest-press tests were completed on both platforms following the training program. Platform (stability ball vs. flat bench) had no influence on strength, but work capacity was initially 12 % lower on the stability ball compared to the flat bench. In response to training, both groups significantly increased strength and work capacity, and there were no group differences. The increase in 1RM strength was 15 % and 16 % on the stability ball and flat bench for the SB group, and 16 % and 19 % for the FB group, respectively. The increase in work capacity was 32 % and 13 % on the stability ball and flat bench for the SB group, and 27 % and 26 % for the FB group, respectively. Both groups significantly improved on the FAPT, and there were no group differences. Performance on the FAPT improved by 5 % for the SB group, and 22 % for the FB group. Performance on the SAPT did not change. Barbell chest-press training performed on either the stability ball or flat bench increased strength and work capacity, and these changes were transferable across platforms. Thus, the stability ball is an effective platform for barbell chest-press training in untrained women over a short duration.

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PMID: 17497582 [PubMed - indexed for MEDLINE]


 
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Electromyographic activity of the trunk stabilizers during stable and unstable bench press.

Norwood JT, Anderson GS, Gaetz MB, Twist PW.

University College of the Fraser Valley, Abbotsford, British Columbia, Canada.

The purpose of this study was to investigate the effectiveness of instability training in the recruitment of core stabilizing muscles during dynamic multijoint movement. Surface electromyography (EMG) was measured from 6 muscles (latissimus dorsi, rectus abdominus, internal obliques, erector spinae, and soleus) while subjects performed a 9.1-kg bench press on stable and unstable surfaces. There were 4 exercises in total: (a) stable surfaces for shoulders and feet, (b) upper-body instability, (c) lower-body instability, and (d) dual instability. Five seconds of EMG were recorded during each bench press and were subsequently smoothed with root mean squares calculated for the entire time-series. A repeated-measures analysis of variance (ANOVA) was used to test overall differences between exercise conditions for each muscle. Paired equal variance t-tests with a stepwise Bonferroni correction for multiple contrasts (alpha = 0.05/total number of contrasts) were performed for muscles with significant repeated-measures ANOVA results. The results show significant increases in EMG with increasing instability. Specifically, the dual instability bench press resulted in the greatest mean muscle activation of the 3 stability conditions, with single instability conditions being significantly greater than the stable condition. This pattern of results is consistent with the position that performing the bench press in a progressively unstable environment may be an effective method to increase activation of the core stabilizing musculature, while the upper- and lower-body stabilizers can be activated differentially depending on the mode of instability.

PMID: 17530936 [PubMed - indexed for MEDLINE]

 
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The effect of continuous repetition training and intra-set rest training on bench press strength and power.

Lawton T, Cronin J, Drinkwater E, Lindsell R, Pyne D.

Strength and Conditioning, Australian Institute of Sport, Belconnen ACT, Australia.

AIM: The purpose of this research was to compare the effects of continuous repetition and intra-set rest training on maximal strength and power output of the upper body. METHODS: The 6 repetition maximum (6RM) and bench press throw power output against masses of 20, 30 and 40 kg of 26 elite junior male basketball and soccer players were tested on 2 separate occasions for reliability purposes. Subjects were then randomly assigned to either a continuous repetition (CR - 4 sets x 6 repetitions) or intra-set rest (ISR - 8 sets x 3 repetitions) training regime over 6-weeks. Volume (sets x repetitions x %6RM) between groups was equated and both groups completed all sets in the same time period (13 minutes and 20 seconds). The total concentric work time was determined to identify differences in training regimes. Independent sample t-tests on preintervention and postintervention percentage change scores were analysed for significant differences (p<0.05). RESULTS: The observed coefficients of variation (1.7% to 4.8%) and intraclass correlation coefficients (r=0.87 to 0.98) indicated stability of these measures across testing occasions. The CR group significantly increased 6RM strength (9.7%) compared with the ISR group (4.9%). The total concentric work time was significantly longer in CR training than ISR (36.03+/- 4.03 s and 31.74+/-4.71 s; p=0.13). Power output increases across the 20, 30 and 40 kg loads ranged from 5.8% to 10.9% for both training groups but the between-group percentage change scores were not significantly different. CONCLUSIONS:Bench press training involving 4 sets of 6 continuous repetitions elicited a greater improvement in bench press strength than 8 sets of 3 repetitions at the same percentage load of their 6RM. Both ISR and CR training were equally effective in increasing power output.

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PMID: 15758847 [PubMed - indexed for MEDLINE]


 
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Effect of post-tetanic potentiation of pectoralis and triceps brachii muscles on bench press performance.

Requena B, Zabala M, Ribas J, Ereline J, Pääsuke M, González-Badillo JJ.

Department of Physical Education and Sport, University of Granada, Spain. brequena@ugr.es

The effect of post-tetanic potentiation (PTP) induced in the pectoralis and triceps brachii muscles by high-frequency submaximal percutaneous electrical stimulation (PES) on average and maximal power attained in bench press throwing was measured in 12 healthy men. Three PES regimens were used: (a) a 7-second and (b) a 10-second trial at 100 Hz, and (c) an intermittent trial with 8 1-second tetanic trains at 100 Hz with rest periods of 20 seconds. Only nonsignificant (p > 0.05) increase was observed in average power at 8 minutes and in maximal power at 5, 8, and 11 minutes after tetanus after 7-second trial, and in maximal power at 5 and 8 minutes after tetanus after an intermittent trial. These data indicate that PES application was a noneffective stimulus for increased bench press performance. A great interindividual variability response was observed and, therefore, PTP induction for improving upper-body muscle performance needs further experiments.

PMID: 16095412 [PubMed - indexed for MEDLINE]

 
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A modified YMCA bench press test as a predictor of 1 repetition maximum bench press strength.

Kim PS, Mayhew JL, Peterson DF.

Department of Physiology, Kirksville College of Osteopathic Medicine, Missouri 63501, USA.

This study evaluated the influence of cadence on the Young Men's Christian Association (YMCA) bench press test for predicting 1 repetition maximum (1RM) bench press test performance. Fifty-eight medical students (37 men, 21 women) were evaluated for anthropometric variables (age, height, weight, fat-free mass, and percent fat), 1RM bench press, and 2 cadence tests of muscular endurance performed at cadences of 30 and 60 repetitions per minute (reps.min(-1)). Each test was performed on a separate day, with 5 days rest in between. There was no significant difference among the number of repetitions performed at each cadence by men, whereas women performed significantly more repetitions at the slower cadence. Repetitions at either cadence were good predictors of 1RM bench press in both genders (men: 30 reps.min(-1), r(2) = 0.757, standard error of the estimate [SEE] = 8.0 kg; 60 reps.min(-1), r(2) = 0.884, SEE = 8.2 kg; women: 30 reps.min(-1), r(2) = 0.754, SEE = 3.1 kg; 60 reps.min(-1), r(2) = 0.816, SEE = 2.7 kg). The addition of anthropometric dimensions to the regression equations did not improve predictive accuracy. Using both fast and slow cadences, the YMCA bench press test can provide a valid estimation of 1RM performance in untrained young men and women.

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PMID: 12173960 [PubMed - indexed for MEDLINE]


 
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A kinetic and electromyographic comparison of the standing cable press and bench press.

Santana JC, Vera-Garcia FJ, McGill SM.

Institute of Human Performance, Boca Raton, Florida 33432, USA.

This study compared the standing cable press (SCP) and the traditional bench press (BP) to better understand the biomechanical limitations of pushing from a standing position together with the activation amplitudes of trunk and shoulder muscles. A static biomechanical model (4D Watbak) was used to assess the forces that can be pushed with 2 arms in a standing position. Then, 14 recreationally trained men performed 1 repetition maximum (1RM) BP and 1RM single-arm SP exercises while superficial electromyography (EMG) of various shoulder and torso muscles was measured. The 1RM BP performance resulted in an average load (74.2 +/- 17.6 kg) significantly higher than 1RM single-arm SP (26.0 +/- 4.4 kg). In addition, the model predicted that pushing forces from a standing position under ideal mechanical conditions are limited to 40.8% of the subject's body weight. For the 1RM BP, anterior deltoid and pectoralis major were more activated than most of the trunk muscles. In contrast, for the 1RM single-arm SP, the left internal oblique and left latissimus dorsi activities were similar to those of the anterior deltoid and pectoralis major. The EMG amplitudes of pectoralis major and the erector muscles were larger for 1RM BP. Conversely, the activation levels of left abdominal muscles and left latissimus dorsi were higher for 1RM right-arm SP. The BP emphasizes the activation of the shoulder and chest muscles and challenges the capability to develop great shoulder torques. The SCP performance also relies on the strength of shoulder and chest musculature; however, it is whole-body stability and equilibrium together with joint stability that present the major limitation in force generation. Our EMG findings show that SCP performance is limited by the activation and neuromuscular coordination of torso muscles, not maximal muscle activation of the chest and shoulder muscles. This has implications for the utility of these exercise approaches to achieve different training goals.

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PMID: 18076235 [PubMed - in process]


 
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Prediction of 1 repetition maximum in high-school power lifters.

Kravitz L, Akalan C, Nowicki K, Kinzey SJ.

Exercise Physiology Laboratories, University of New Mexico, Johnson Center #1160, Albuquerque, New Mexico 87111, USA. lkravitz@unm.edu

Eighteen elite male power lifters performed 1-repetition maximum (1RM) and submaximal strength tests (70, 80, and 90% 1RM) to develop prediction equations for the squat (SQ), bench press (BP), and deadlift (DL) exercises. For each equation, stepwise multiple-regression prediction procedure included the maximum number of repetitions (REPS) completed at a given %1RM weight (REPWT). For SQ and BP the 70% 1RM yielded the best 1RM prediction equations: (1RM SQ [kg]) = 159.9 + (0.103 x REPS x REPWT) + (-11.552 x REPS), with a standard error of the estimate (SEE) of 5.06 kg; (1RM BP [kg]) = 90.66 + (0.085 x REPS x REPWT) + (-5.306 x REPS), with an SEE of 2.69 kg. For DL the 80% 1RM yielded the best prediction equation: (1RM DL [kg]) = 156.08 + (0.098 x REPS x REPWT) + (-12.106 x REPS), with an SEE of 4.97 kg. The athlete's years lifted (number of years of power lifting experience) was highly correlated with the 1RM strength for BP and DL (r > 0.70) but not for SQ (r < 0.70). No bodily structural dimension variable had a significant correlation with 1RM strength (r < 0.70). The results of this study indicate that 1RM SQ, BP, and DL may be predicted with an acceptable degree of accuracy in elite male high-school power lifter subjects.

PMID: 12580673 [PubMed - indexed for MEDLINE]

 
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The effects of competition and the presence of an audience on weight lifting performance.

Rhea MR, Landers DM, Alvar BA, Arent SM.

Exercise Science Research Institute, Arizona State University, Tempe, Arizona 85287, USA. matthew.rhea@asu.edu

The purpose of this investigation was to examine the effects of the presence of an audience and competition on maximal weight lifting performance. Thirty-two recreationally trained participants (15 men, 17 women; 21 +/- 2.5 years) performed a 1 repetition maximum (1 RM) bench press during 3 different situations (coaction, competitive coaction, and audience condition). Subjects also completed the Activation-Deactivation Adjective Checklist Short Form following the 3 trials to measure arousal state during each of the 3 trials. Significant differences (p < 0.05) were found between competitive coaction and coaction trials as well as between audience and coaction trials. Both men and women demonstrated the highest performance in front of an audience (105 +/- 48 kg) followed by competition (103 +/- 46 kg) and then the coaction trial (93 +/- 43 kg). No significant difference in arousal was measured between trials. The data suggest that performing a maximal lift in the presence of an audience or in competition facilitates performance and support the self-presentation and self-awareness theories. Social facilitation effects should be controlled in research settings and may aid the performance of weight lifting activities during events or competition.

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PMID: 12741867 [PubMed - indexed for MEDLINE]


 
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Partial rupture of the pectoralis major muscle in athletes.

Roi GS, Respizzi S, Dworzak F.

Dipartimento di Scienze e Tecnologie Biomediche, Università di Milano, Italy.

Partial rupture of the pectoralis major muscle is quite a rare event in sports traumatology and information about its treatment is lacking in literature. In this paper the long term effect of conservative non-surgical treatment in two body-builders and one shot-putter is discussed, who reported the partial rupture while performing bench lifts with barbells. Functional recovery was evaluated a few years after the injury (from 4 to 7) with an isokinetic dynamometer (Cybex II, Lumex INC N.Y.), measuring maximal shoulder adduction-abduction torques at different angular speeds (60, 180, and 300 degrees/s). The results were compared with those of five healthy athletes practicing either body-building or weight-lifting. From the present study we conclude the following: the non-invasive treatment of a partial rupture of the pectoralis major muscle may produce almost complete functional recovery; in normal subjects adduction muscles are advantageous in comparison to the abduction ones.

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PMID: 2318568 [PubMed - indexed for MEDLINE]


 
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"Psyching-up" enhances force production during the bench press exercise.

Tod DA, Iredale KF, McGuigan MR, Strange DE, Gill N.

Biomechanical Laboratory, Centre for Sport and Exercise Science, Waikato Institute of Technology, Hamilton, New Zealand. dvt@aber.ac.uk

We investigated the effect of "psyching-up" on force production during the bench press. Twelve men (mean age +/- SD: 27.4 +/- 11.2 years) and 8 women (20.9 +/- 2.5 years) with strength-training experience performed 5 bench press repetitions on a modified Biodex isokinetic dynamometer during 3 interventions. The interventions were counterbalanced and included a free-choice psych-up, a cognitive distraction, and an attention-placebo. Peak force recorded after psyching-up (mean +/- SD: 764 +/- 269 N.m) was significantly different from both distraction (703 +/- 282 N.m, p = 0.003) and attention-placebo (708 +/- 248 N.m, p = 0.01). The mean percentage increase in peak force from distraction to psyching-up was 11.8% (6 to 18%, 95% confidence interval [CI]) and 8.1% from placebo to psyching-up (3 to 13%, 95% CI). The results of the present study indicate that psyching-up may increase force production during the bench press exercise in participants with at least 1 year strength-training experience.

Publication Types:


PMID: 16095409 [PubMed - indexed for MEDLINE]

Items 1 - 3 of 3
One page.
 
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Fatigue effects on bar kinematics during the bench press.

Duffey MJ, Challis JH.

Biomechanics Laboratory, University Park, The Pennsylavania Stae University, Pennsylvania 16802, USA.

The bench press is one of the most popular weight training exercises. Although most training regimens incorporate multiple repetition sets, there are few data describing how the kinematics of a lift change during a set to failure. To examine these changes, recreational lifters (10 men and 8 women) were recruited. The maximum weight each subject could bench press (1RM) was determined. Subjects then performed as many repetitions as possible at 75% of the 1RM load. Three-dimensional kinematic data were recorded and analyzed for all lifts. Statistical analysis revealed that differences between maximal and submaximal lifts and the kinematics of a submaximal lift change as a subject approaches failure in a set. The time to lift the bar more than doubled from the first to the last repetition, causing a decrease in both mean and peak upward velocity. Furthermore, the peak upward velocity occurred much earlier in the lift phase in these later repetitions. The path the bar followed also changed, with subjects keeping the bar more directly over the shoulder during the lift. In general, most of the kinematic variables analyzed became more similar to those of the maximal lift as the subjects progressed through the set, but there was considerable variation between subjects as to which repetition was most like the maximal lift. This study shows that there are definite changes in the lifting kinematics in recreational lifters during a set to failure and suggests it may be particularly important for coaches and less-skilled lifters to focus on developing the proper bar path, rather than reaching momentary muscular failure, in the early part of a training program.

PMID: 17530967 [PubMed - indexed for MEDLINE]

 
Related Articles, Links

Validation of an optical encoder during free weight resistance movements and analysis of bench press sticking point power during fatigue.

Drinkwater EJ, Galna B, McKenna MJ, Hunt PH, Pyne DB.

School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia. edrinkwater@csu.edu.au

During the concentric movement of the bench press, there is an initial high-power push after chest contact, immediately followed by a characteristic area of low power, the so-called "sticking region." During high-intensity lifting, a decline in power can result in a failed lift attempt. The purpose of this study was to determine the validity of an optical encoder to measure power and then employ this device to determine power changes during the initial acceleration and sticking region during fatiguing repeated bench press training. Twelve subjects performed a free weight bench press, a Smith Machine back squat, and a Smith Machine 40-kg bench press throw for power validation measures. All barbell movements were simultaneously monitored using cinematography and an optical encoder. Eccentric and concentric mean and peak power were calculated using time and position data derived from each method. Validity of power measures between the video (criterion) and optical encoder scores were evaluated by standard error of the estimate (SEE) and coefficient of variation (CV). Seven subjects then performed 4 sets of 6 free weight bench press repetitions progressively increasing from 85 to 95% of their 6 repetition maximum, with each repetition continually monitored by an optical encoder. The SEE for power ranged from 3.6 to 14.4 W (CV, 1.0-3.0%; correlation, 0.97-1.00). During the free weight bench press training, peak power declined by approximately 55% (p < 0.01) during the initial acceleration phase of the final 2 repetitions of the final set. Although decreases in power of the sticking point were significant (p < 0.01), as early as repetition 5 (-40%) they reached critically low levels in the final 2 repetitions (>-95%). In conclusion, the optical encoder provided valid measures of kinetics during free weight resistance training movements. The decline in power during the initial acceleration phase appears a factor in a failed lift attempt at the sticking point.

Publication Types:


PMID: 17530976 [PubMed - indexed for MEDLINE]


 
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Ratings of perceived exertion and muscle activity during the bench press exercise in recreational and novice lifters.

Lagally KM, McCaw ST, Young GT, Medema HC, Thomas DQ.

Biomechanics Laboratory, School of Kinesiology and Recreation, Illinois State University, Normal, Illinois 61790, USA. kmlagal@ilstu.edu

This study examined ratings of perceived exertion (RPE) and electromyography (EMG) during resistance exercise in recreational and novice lifters. Fourteen novice (age = 21.5 +/- 1.5 years) and 14 recreationally trained (age = 21.9 +/- 2.2 years) women volunteered to perform the bench press exercise at 60 and 80% of their 1 repetition maximum (1RM). RPE and EMG were measured during both intensities. Statistical analyses revealed that active muscle RPE increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (12.32 +/- 1.81 vs. 15.14 +/- 1.74). Integrated EMG also increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (in the pectoralis major; 98.62 +/- 17.54 vs. 127.98 +/- 29.02). No significant differences in RPE or EMG were found between novice and recreational lifters. These results indicate that RPE is related to the relative exercise intensity lifted as well as muscle activity during resistance exercise for both recreational and novice lifters. These results support the use of RPE as a method of resistance exercise intensity estimation for both types of lifters.

Publication Types:


PMID: 15142009 [PubMed - indexed for MEDLINE]