Wyniki wyszukiwania - Biblioteka Nauki

1

The Effects of Load and Effort-Matched Concentric and Eccentric Knee Extension Training in Recreational Females

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Fisher J. , Langford C.

Human Movement

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2014

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tom 15

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nr 3

147-151

EN

Purpose. The purpose of this study was to compare the effects of load and intensity of effort-matched concentric and eccentric knee extension training on isometric strength. Methods. Unilateral isometric torque was measured using a MedX knee extension after which eleven recreationally trained females performed both concentric-only (CONC) and eccentric-only (ECC) unilateral knee extension exercise once per week for 8 weeks. Participants performed a single set of both CONC and ECC exercise loadmatched at 80% of maximum isometric torque for each condition. All participants exercised to repetition maximum in both CONC and ECC conditions at a pace of ~3 s duration for each muscle action. This ensured that participants exercised to the same intensity of effort for both CONC and ECC training interventions. Results. Analyses revealed significant increases in isometric torque for both CONC (14.8%) and ECC (13.0%) conditions (p < 0.05). Absolute change from pre- to post-intervention was compared for CONC and ECC training conditions revealing no statistically significant differences (p > 0.05). Effect sizes are reported as 0.60 (CONC) and 0.53 (ECC). In addition, analyses revealed significantly greater mean total training volume for ECC compared with CONC conditions (15903 vs. 8091, respectively; p < 0.001). Conclusions. The present findings indicate that, when matched for intensity of effort, both CONC and ECC knee extension exercise can significantly improve strength to the same extent. This supports previous research that load and repetitions are not as important as intensity of effort in resistance exercise.

2

Aerobic and Anaerobic Energy During Resistance Exercise at 80% 1RM

100%

Vianna J. , Lima J. , Saavedra F. , Reis V.

Journal of Human Kinetics

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2011

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tom 29A

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nr Special Issue

69-74

EN

The present study investigated the accumulated oxygen deficit (AOD) method to assess the energy cost in resistance exercises (RE). The aim of the study was to evaluate the aerobic and anaerobic energy release during resistance exercises performed at 80% 1-RM in four exercises (half squat, bench press, triceps extension and lat pull down), as well as the accuracy of its estimation. The sample comprised 14 men (age = 26.6 ± 4.9 years; height = 177.7 ± 0.1 cm; body mass = 79.0 ± 11.1 kg; and estimated fat mass = 10.5 ± 4.6%). Test and re-test of 1-RM were applied to every exercise. Low-intensity bouts at 12, 16, 20, and 24% of 1-RM were conducted. Energy cost was then extrapolated to 80% 1-RM exhaustive bout and relative energy contribution were assessed. By utilizing the AOD method, the results of the present study suggest a great proportion of anaerobic metabolism during exercise at 80% 1-RM in the four RE that were analyzed: Bench press = 77,66±6,95%; Half squat = 87,44±6,45%; Triceps extension = 63,91±9,22%; Lat pull down = 71,99±13,73 %. The results of the present study suggest that AOD during resistance exercises presents a pattern that does not match the reports in the literature for other types of exercise. The accuracy of the total energy demand estimation at 80% 1-RM was acceptable in the Bench press, in the Triceps extension and in the Lat pull down, but no in the Half squat. More studies are warranted to investigate the validity of this method in resistance exercise.

3

Can Energy Cost During Low-Intensity Resistance Exercise be Predicted by the OMNI-RES Scale?

100%

Vianna J. , Reis V. , Saavedra F. , Damasceno V. , Silva S. , Goss F.

Journal of Human Kinetics

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2011

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tom 29A

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nr Special Issue

75-82

EN

The aim of the present study was to assess the precision of the OMNI-RES scale to predict energy cost (EC) at low intensity in four resistance exercises (RE). 17 male recreational body builders (age = 26.6 ± 4.9 years; height = 177.7 ± 0.1 cm; body weight = 79.0 ± 11.1 kg and percent body fat = 10.5 ± 4.6%) served as subjects. Initially tests to determine 1RM for four resistance exercises (bench press, half squat, lat pull down and triceps extension) were administered. Subjects also performed resistance exercise at 12, 16, 20, and 24% of 1RM at a rate of 40 bpm until volitional exhaustion. Oxygen uptake (VO2) and rate of perceived exertion (RPE) using the OMNI-RES were obtained during and after all RE. EC was calculated using VO2 and the caloric values of VO2 for non-protein RER. Regression analyses were performed for every RE, using EC as the dependent and RPE as the predictor variable. The triceps extension, lat pull down and bench press, RPE correlated strongly with EC (R > 0.97) and predicted EC with a error of less than 0.2 kcal.min-1. In conclusion, RPE using the OMNI-RES scale can be considered as an accurate indicator of EC in the bench press, lat pull down and triceps extension performed by recreational bodybuilders, provided lower intensities are used (up to 24% of 1-RM) and provided each set of exercise is performed for the maximal sustainable duration. It would be interesting in future studies to consider having the subjects exercise at low intensities for longer durations than those in the present study.

4

Influence of Resistance Training on Blood Pressure in Patients with Metabolic Syndrome and Menopause

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Cardoso G. A. , Silva A. S. , Araújo de Souza A. , Pereira dos Santos M. A. , Brito da Silva R. S. , Mateus de Lacerda L. , Motae M. P.

Journal of Human Kinetics

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2014

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tom 43

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nr 1

87-95

EN

This study investigated the chronic and acute influence of resistance exercise on blood pressure in women with metabolic syndrome before and after climacteric. Twenty sedentary women, nine non-menopausal (RNM) and 11 menopausal (RM), performed training for 12 weeks. Meanwhile, 23 controls, 11 not menopausal (CNM) and 12 menopausal (CM), remained sedentary. Blood pressure was measured before and after the training period in conditions of rest and after a session of exercise. Training promoted variations in blood pressure at rest from 116±13 to 118±10 mmHg (p=0.73) and from 128±12 mmHg to 120±11mmHg (p=0.12) in RNM and RM, respectively. CNM and CM varied from 115±11 to 116±12 mmHg (p=0.9) and from 115±14 mmHg to 116±13 mmHg (p=0.74). Blood pressure values in one acute session did not differ between groups (p>0.05). Resistance training did not improve blood pressure in women with metabolic syndrome, regardless of climacteric.

5

Relationship Between Fatigue Index and Number of Repetition Maxima with Sub-Maximal Loads in Biceps Curl

100%

Pekünlü E. , Atalağ O.

Journal of Human Kinetics

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2013

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tom 38

169-181

EN

The aim of this study was to investigate the relationship between the number of repetition maxima to volitional failure (RM) at 60%, 75%, 90% of 1RM and fatigue index (FI), a determinant of the muscular endurance level. Thirty four resistance trained male participants attended two testing sessions. The first session was conducted to assess 1RM load and RM at 60%, 75% and 90% of 1RM in the supine biceps curl (SBC) exercise. In the second session, a FI test protocol consisting of five sets of SBC with 90 s rest between sets was performed to determine FI values. Each set was performed to volitional failure using a sub-maximal load in the range of 15-20RM. Hypothetical high FI and low FI groups (17 participants with the highest and lowest FI values, respectively) were formed for statistical analyses. ANOVA results revealed that RM at 60%, 75%, 90% of 1RM were not significantly different between FI groups when controlled for mean repetition tempo (p=0.11, p=0.38, p=0.13, respectively). Pearson’s correlation coefficients revealed that no significant relationship was present between FI values and RM at 60%, 75%, 90% of 1RM (p=0.40, p=0.46, p=0.14, respectively). In conclusion, the muscular endurance level of participants defined in terms of FI value was not an indicator of RM in SBC. Therefore, athletes with different muscular endurance levels can use similar percentages of 1RM in biceps curl exercise in their training programs when the aim is to elicit training adaptations related to specific RM zones.

6

An Efficient Method of Key-Frame Extraction Based on a Cluster Algorithm

100%

Moir G. L. , Graham B. W. , Davis S. E. , Guers J. J. , Witmer C. A.

Journal of Human Kinetics

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2013

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tom 39

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nr 1

15-23

EN

The purpose of the present study was to investigate the effects of different configurations of repetitions within a set of deadlifts on the mechanical variables of concentric force, concentric time under tension, impulse, work, power, and fatigue. Eleven resistance trained men (age: 21.9 ± 1.0 years; deadlift 1 repetition maximum: 183.2 ± 38.3 kg) performed four repetitions of the deadlift exercise with a load equivalent to 90% of 1 repetition maximum under three different set configurations: Traditional (continuous repetitions); Doubles cluster (repetitions 1 and 2, and 3 and 4 performed continuously with a 30 s rest inserted between repetitions 2 and 3); Singles cluster (30 s rest provided between repetitions). The order of the sessions was counterbalanced across the subjects and the mechanical variables were calculated during each repetition from the synchronized signals recorded from force platforms and a motion analysis system. Relative to the Traditional set, the insertion of rest periods in the cluster set configurations resulted in greater time under tension (p < 0.001) and therefore, greater impulse (p < 0.001) during the repetitions. Reductions in power were observed during the cluster sets compared to the Traditional set (p = 0.001). The Doubles cluster set resulted in greater fatigue scores for power compared to the Traditional set (p = 0.04). The influence of cluster sets on mechanical variables appears to be mediated by the mechanical characteristics of the exercise (i.e. stretch-shortening cycle) and the competing physiological mechanisms of fatigue and potentiation.

7

Acute effects of dropsets among different resistance training methods in upper body performance

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Melibeu Bentes C. , Simão R. , Bunker T. , Rhea M. R. , Miranda H. , Matassoli Gomes T. , Da Silva Novaes J.

Journal of Human Kinetics

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2012

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tom 34

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nr 1

105-111

EN

The aim of this study was to compare the influence of including dropset exercises in different orders, both in the pre-exhaustion, as in the post-exhaustion method, and to analyze the performance of total work on the bench press and chest flying exercise. Twenty-two male volunteers with a recreational experience in ST were evaluated in six visits in non-consecutive days, at approximately the same time of the day. During the first visit, subjects signed an informed consent form and underwent an anthropometric evaluation and testing of 10RM. The second visit involved a re-test of 10RM. From third to sixth visits, the subjects were randomly grouped into the following experimental situations: 3rd Visit (V3 - Post-exhaustion): Bench Press (dropset) + Chest Flying (10RM); 4th visit (V4 - Post-exhaustion): Bench Press (10RM) + Chest Flying (dropset); 5th Visit (V5 - pre-exhaustion): Chest Flying (dropset) + Bench Press (10RM); 6th Visit (V6 - pre-exhaustion): Chest Flying (10RM) + Bench Press (dropset). The protocol of dropset was performed with 3 sets and no rest intervals 10RM + 80% 10RM + 60% 10RM. An interval between sets was adopted for 2 minutes. The primary results showed a significant difference in Total Work for visits V3 and V6, which was included in the dropset multiarticular exercises. These results suggest that the exercise order with the dropset method in the preexhaustion or post-exhaustion methods had an acute influence on Total Work.

8

Central and Peripheral Fatigue During Resistance Exercise – A Critical Review

88%

Zając A. , Chalimoniuk M. , Gołaś A. , Lngfort J. , Maszczyk A.

Journal of Human Kinetics

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2015

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tom 49

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nr 1

159-169

EN

Resistance exercise is a popular form of conditioning for numerous sport disciplines, and recently different modes of strength training are being evaluated for health benefits. Resistance exercise differs significantly in nature, and several variables determine the direction and range of adaptive changes that occur in the muscular and skeletal system of the body. Some modes of resistance training can also be effective in stimulating the cardiovascular system. These variables include exercise selection (general, specific, single or multi joint, dynamic, explosive), type of resistance (free weights, variable resistance, isokinetics), order of exercise (upper and lower body or push and pull exercises), and most of all the training load which includes intensity expressed as % of 1RM, number of repetitions, number of sets and the rest interval between sets. Manipulating these variables allows for specific adaptive changes which may include gains in muscle mass, muscle strength or muscle endurance. It has been well established that during resistance exercise fatigue occurs, regardless of the volume and intensity of work applied. The peripheral mechanisms of fatigue have been studied and explained in more detail than those related to the CNS. This review is an attempt to bring together the latest knowledge regarding fatigue, both peripheral and central, during resistance exercise. The authors of this review concentrated on physiological and biochemical mechanisms underlying fatigue in exercises performed with maximal intensity, as well as those performed to exhaustion with numerous repetitions and submaximal load.

9

Energy Expenditure Combining Strength and Aerobic Training

88%

Vilaça J. , Bottaro M. , Santos C.

Journal of Human Kinetics

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2011

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tom 29A

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nr Special Issue

21-25

EN

The combination of Strength Training (ST) with Aerobic Training (AT) exercises in the same training session, which commonly appears in literature as the concurrent training, is widely used in fitness and physical condition programs, especially when the aim is to increase the energy expenditure during and after training session. The aim of this study was to identify, through literature, whether the combination of exercises of the ST with exercises of the AT allows changes in body composition and energy expenditure during and after the training session. Chronic studies have showed a positive effect on body composition (decreased in relative body fat) when the ST are combined with AT. Similarly, the acute effects of the order of combining these two types of exercise does not seem to affect energy expenditure, measured by oxygen consumption (VO2), during the training session and only change this expenditure in the first 15 minutes after the training session. In conclusion, we can say that the studies indicate that the combination of exercises of the ST with exercises of the AT has a positive effect on changes in body composition, and energy expenditure during and after training sessions.

10

Effect of Fatigue Upon Performance and Electromyographic Activity in 6-RM Bench Press

88%

Tillaar R. v. d. , Saeterbakken A.

Journal of Human Kinetics

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2014

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tom 40

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nr 1

57-65

EN

The aim of this study was to examine the effect of fatigue during one set of 6-RM bench pressing upon the muscle patterning and performance. Fourteen resistance-trained males (age 22.5±2.0 years, stature 1.82±0.07 m, body mass 82.0±7.8 kg) conducted a 6-RM bench press protocol. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were measured in each repetition during the 6-RM bench press. Total lifting time increased and the velocity in the ascending movement decreased (p≤0.001). However, the kinematics in the descending phase deferred: the time decreased and velocity increased during the 6-RM (p≤0.001). Generally, muscles increased their EMG amplitude during the six repetitions in the ascending movement, while only three of the seven measured muscles showed an increase over the six repetitions in the descending part in 6-RM bench pressing. It was concluded that the bench pressing performance decreased (lower barbell velocities and longer lifting times) with increasing fatigue in the 6-RM execution. Furthermore EMG increased in the prime movers and the trunk stabilizers (abdominal and spine), while the antagonist muscle (biceps) activity was not affected by fatigue during the lifting phase in a single set of 6-RM bench pressing

11

Intermittent resistance exercise: evolution from the steady state

63%

Scott C. B.

Central European Journal of Sport Sciences and Medicine

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2014

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tom 06

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nr 2

EN

Oxygen uptake measurements are without question useful and a staple measurement for the estimation of exercise energy costs. However, steady state models cannot be used to successfully model intermittent resistance exercise energy costs. Our laboratory has taken steps to avoid such comparisons between these discrepant exercises. We have separated out exercise and recovery periods during resistance training and utilize capacity (kJ) estimates as opposed to rate measures (kJ min–1). Moreover, we avoid anaerobic threshold concepts as applied to resistance exercise. When viewed accordingly, resistance exercise energy costs are opposite those of the steady state model: exercise oxygen uptake is highest for steady state exercise and lowest for resistance exercise, recovery oxygen uptake can be the highest energy cost for resistance exercise whereas for steady state exercise it may or may not be meaningful, and anaerobic energy costs represent a significant component of resistance exercise that plays little to no role with steady state exercise.