Maximal Muscular Strength Research Articles

Improving Power Output in Older Adults Using Plyometrics in a Body Mass-Supported Treadmill.

Dobbs, TJ, Simonson, SR, and Conger, SA. Improving power output in older adults using plyometrics in a body mass-supported treadmill. J Strength Cond Res 32(9): 2458-2465, 2018-The purpose of this study was to determine if performing plyometrics in a body mass-supported treadmill would lead to greater increases in power output and functional strength in older adults compared with traditional strength training. Twenty-three participants were randomized to strength (SG, n = 8), plyometric (PG, n = 8), or control (CG, n = 7) groups. The SG and PG exercised 3 times per week for 8 weeks, whereas the CG performed no exercise. Timed sit-to-stand and stair climb, estimated maximal muscular isotonic strength, and isokinetic strength were assessed pre- and posttraining. Significant improvements occurred in the PG vs. CG in the timed chair sit-to-stand (22.11 ± 8.48%; p = 0.013), timed stair climb (14.68 ± 6.28%; p = 0.002), and stair climb power (16.59 ± 9.07%; p < 0.001). PG and SG significantly increased their estimated 1 repetition maximum in the leg extension and single leg lunge (p < 0.05), and PG was significantly more powerful at all 3 velocities in both flexion and extension compared with SG and CG ranging from 24.54 to 61.85% (p < 0.001) except for 60°·s extension during isokinetic testing. Eight weeks of plyometrics in a body mass-supported treadmill can significantly improve functional strength and power in older adults. In this study, the PG increased muscular strength at the same rate or better than the SG without performing any resistance training. The PG also outperformed SG during the functional tests. These results suggest that plyometrics, if modified and performed in a safe environment, can increase muscular strength and power and improve functional abilities in older adults.

Acute Effects of Resistance Exercise in Depressed Black/African American People Living with HIV

In the US, Blacks/African Americans (AA) comprise the largest proportion of People Living with HIV (PLWH). Depressive symptoms and fatigue are highly prevalent among PLWH. Depressive symptoms are linked to progression of HIV disease, and fatigue is linked to severity of depressive symptoms. Resistance exercise (RE) is shown to have psychological benefits in non-HIV depressed populations, and these benefits are hypothesized to be intensity-dependent. To date, no study has examined the use of a single bout of RE for management of affect and fatigue with depressed PLWH. PURPOSE: To test the acute effects of RE intensity on affect, arousal, and distress among sedentary AA PLWH who screen positive for depression. METHODS: Twenty-five men and 17 women ages 24-66 (47.5±11.2) with a Center for Epidemiologic Studies Depression Scale score of ≥10 completed a battery of questionnaires and 10 repetition maximum (10RM) muscular strength tests. Participants were randomized into: moderate intensity RE (MRE) (i.e., 70% of 10RM), n=21, or vigorous intensity RE (VRE) (i.e., 100% of 10RM), n=21. They had to complete 3 sets of 10 repetitions for 5 exercises. Affect, arousal, and distress were measured with the Feeling Scale, Felt Arousal Scale, and Subjective Units of Distress Scale, respectively. Measures were administered at PRE, MID, POST, at 15-minute DELAY, and at 30-minute DELAY. Changes were analyzed using ANOVAs, with Bonferroni adjustments. RESULTS: There were significant group x time interactions for affect (p<.05), and distress (p<.01), and main effect of time for arousal (p<.01). With MRE, affect improved PRE to POST (p<.01), PRE to DELAY15 (p<.01), and PRE to DELAY30 (p<.01), and arousal increased PRE to MID, and PRE to POST (p’s<.01). In addition, distress reduced PRE to all time points (p’s<.01). With VRE, affect decreased PRE to MID (p<.01), while arousal increased PRE to MID, and PRE to POST (p’s<.01). In addition, distress reduced PRE to Delay15 (p<.01), and PRE to DELAY30 (p<.01). CONCLUSIONS: Results suggest that an acute bout of MRE is more effective than VRE in improving affect, increasing energy, and reducing distress in depressed AA PLWH. However, VRE also appears to have distress-reducing benefits. These findings should be considered when prescribing exercise for symptom management in this population.

Muscular Strength is Independently Associated with Cystatin C: The KORA-Age Study.

The purpose of this study was to investigate if there is a link between muscular strength (MS) and markers of chronic kidney disease (CKD) among older adults. The cross-sectional analysis based on 1041 men and women, aged 65-94 years, who participated in the KORA-Age study. Participants underwent an interview and extensive examinations including anthropometric measurements, diseases and drug intake registration, determination of health-related behaviors, collection of blood samples for measurements of cystatin C and maximal muscle strength evaluation. One-Way ANOVA revealed significant differences in both mean cystatin C (1.16±0.37 vs. 1.03±0.29 vs. 0.93±0.24 mg/L, p<0.001) and mean eGFRcysC (63.61±18.61 vs. 72.14±18.92 vs. 79.87±18.19 ml/min/1.73 m2, p<0.05) across thirds of maximal muscular strength (from lowest to highest). MS in the lowest third was significantly associated with increased odds of having elevated cystatin C (OR: 1.70, 95% CI: 1.01-2.85, p=0.043) after controlling for age, gender, fat mass, fat-free mass, alcohol intake, smoking status, number of regularly used medications, multimorbidity status, hs-CRP, telomere length and levels of physical activity. Lower levels of MS are independently associated with higher concentrations of cystatin C and lower eGFRcysC in older individuals. Increasing the levels of muscular strength may be useful to prevent the age-related CKD disease of older adults.

The Importance of Muscular Strength: Training Considerations.

This review covers underlying physiological characteristics and training considerations that may affect muscular strength including improving maximal force expression and time-limited force expression. Strength is underpinned by a combination of morphological and neural factors including muscle cross-sectional area and architecture, musculotendinous stiffness, motor unit recruitment, rate coding, motor unit synchronization, and neuromuscular inhibition. Although single- and multi-targeted block periodization models may produce the greatest strength-power benefits, concepts within each model must be considered within the limitations of the sport, athletes, and schedules. Bilateral training, eccentric training and accentuated eccentric loading, and variable resistance training may produce the greatest comprehensive strength adaptations. Bodyweight exercise, isolation exercises, plyometric exercise, unilateral exercise, and kettlebell training may be limited in their potential to improve maximal strength but are still relevant to strength development by challenging time-limited force expression and differentially challenging motor demands. Training to failure may not be necessary to improve maximum muscular strength and is likely not necessary for maximum gains in strength. Indeed, programming that combines heavy and light loads may improve strength and underpin other strength-power characteristics. Multiple sets appear to produce superior training benefits compared to single sets; however, an athlete's training status and the dose-response relationship must be considered. While 2- to 5-min interset rest intervals may produce the greatest strength-power benefits, rest interval length may vary based an athlete's training age, fiber type, and genetics. Weaker athletes should focus on developing strength before emphasizing power-type training. Stronger athletes may begin to emphasize power-type training while maintaining/improving their strength. Future research should investigate how best to implement accentuated eccentric loading and variable resistance training and examine how initial strength affects an athlete's ability to improve their performance following various training methods.

Exercise at an onsite facility with or without direct exercise supervision improves health‐related physical fitness and exercise participation: An 8‐week randomised controlled trial with 15‐month follow‐up

Physical activity and exercise participation is limited by a perceived lack of time, poor access to facilities and low motivation. The aim was to assess whether providing an exercise program to be completed at the workplace with or without direct supervision was effective for promoting health-related physical fitness and exercise participation. Fifty university employees aged (Mean±SD) 42.5±11.1years were prescribed a moderate- to vigorous-intensity aerobic and resistance exercise program to be completed at an onsite facility for 8weeks. Participants were randomly allocated to receive direct exercise supervision or not. Cardiorespiratory fitness (V̇O2max ) and maximal muscular strength were assessed at baseline and 8 weeks. Self-report physical activity was assessed at baseline, 8 weeks and 15 months post-intervention. Attendance or exercise session volume were not different between groups. Cardiorespiratory fitness (Mean±95% CI); +1.9±0.7mL·kg·min-1 ; P<.001), relative knee flexion (+7.4±3.5Nm·kg-1 %; P<.001) and extension (+7.4±4.6 Nm·kg-1 %; P<.01) strength increased, irrespective of intervention group. Self-reported vigorous-intensity physical activity increased over the intervention (mean±95% CI; +450±222 MET·minutes per week; P<.001), but did not remain elevated at 15 months (+192±276 MET·minutes per week). Providing a workplace exercise facility to complete an individually-prescribed 8-week exercise program is sufficient to improve health-related physical fitness in the short-term independent to the level of supervision provided, but does not influence long-term participation. SO WHAT?: Lower cost onsite exercise facility supervision is as effective at improving physical health and fitness as directly supervised exercise, however ongoing support may be required for sustained physical activity behaviour change.

Maksimalna sila stiska šake u funkciji preciznosti i tačnosti gađanja iz službenog pištolja CZ 99 - generički modeli

Gun training with official weapons is one of the most important training activities in the police. The aim of this paper is to determine the relations and define the prediction model between the accuracy and precision of pistol shooting, as a specific motoric task, and the maximum muscular strength of the hand grip, as a basic indicator of general physical hand preparation. The sample covered a total of 46 subjects: students of the Faculty of Sport and Physical Education who selected the subject Shooting within the study program (N = 19, 11 male students and 8 female students), active Ministry of the Interior officers (N = 6), competitors in practical shooting, IPSC (N = 4), recreational shooters (N = 10, 8 men and 2 women), and beginners (N = 7) who have only passed one hour of basic training in firearms. For the measurement of the maximal muscle force of the hand finger flexor, a standardized test - 'grip of the hand' was used while the shooting was carried out from the CZ 99 handgun, using the precision shot method from a distance of 6 meters. Criterion variables were: accuracy and precision of shooting, while the predictive variables were the maximum forces of the left and right hand, as well as a summary indicator of the achieved maximum force level of both hands. Based on the obtained results, it can be concluded that the accuracy of shooting statistically correlates with the following variables: inversely proportional to the accuracy (r = -0.889, p = 0.000) and proportional to all variables of the maximum force of hand grip, as measures of the strength of the upper extremities ( Fmax_R, Fmax_L and Fmax_SUM at r = 0.437, p = 0.002, r = 0.439, p = 0.002 ir = 0.443, p = 0.002, respectively). In relation to the accuracy of the shooting, a statistically significant but inversely proportional correlation with all variables of the maximum force of the hand grip were determined (Fmax_R, Fmax_L and Fmax_SUM at r = -0.356, p = 0.015, r = -0.375, p = 0.010 ir = -0.369, p = 0.012, respectively). In general, based on the obtained results of this study, it can be concluded that the maximum force of the hand grip, as an indicator of arm strength, is statistically significant, and at the level of influence of 19.3% positively influences the accuracy, i.e. with 13.4% positively affects the accuracy of the shooting from the CZ 99 official handgun in a precision shooting situation from a distance of 6 meters.

Comparing the effects of two distinct eccentric modalities to traditional resistance training in resistance trained, higher functioning older adults

BackgroundThe effects of eccentric resistance exercise are of interest in the older adult cohort, but to our knowledge, there is no research on the relative effects of different eccentric modalities on a range of outcomes in higher functioning, resistance trained older adults. Methods33 resistance-trained older adults (aged 67±4.5years) were randomized into one of three supervised training groups: traditional (TRE), eccentric only (ERE) or eccentrically biased resistance exercise (EBRE) on a 45°, plate-loaded leg press machine. Participants trained twice per week with maximal strength, functional capacity, body composition and blood biomarkers measured before and after the eight-week intervention. ResultsBoth eccentric and concentric strength, and important functional tasks for independent living significantly improved independent of group. Body composition and blood biomarkers were found to significantly improve in the EBRE group only however, no statistical differences were found between groups. ConclusionCompared to traditional resistance training, the two eccentric modalities investigated here were equally effective for improvements in maximum muscular strength, functional capacity, body composition and metabolic biomarkers. When training the resistance trained older adult, very heavy isoinertial external loads (at least 70% of one repetition maximum) are effective irrespective of contraction mode. With heavy strength training, resistance trained older adults can continue to expect improvements in health and function.

Effects of Resistance Training and Protein Supplementation in Breast Cancer Survivors

This study aimed to evaluate 12 wk of resistance training (RT; n = 16) and protein supplementation (RT + protein; n = 17) on muscular strength, body composition, and blood biomarkers of muscle (insulin-like growth factor 1 [IGF-1]), fat (adiponectin), and inflammation (human C-reactive protein [CRP]) in breast cancer survivors (BCS). Thirty-three BCS (59 ± 8 yr) were measured pre- and posttraining for one-repetition maximum (1-RM) muscular strength (chest press and leg extension), body composition (lean mass [LM] and fat mass [FM]) via dual-energy x-ray absorptiometry, and serum concentrations of IGF-1, adiponectin, and CRP. RT consisted of 2 d·wk using 10 exercises for two sets of 10-12 repetitions and a third set to failure at ~65%-85% of 1-RM. RT + protein consumed 20 g of protein twice a day. ANOVA was used for analyses. Significance was set at P ≤ 0.05. Average RT intensity was 65%-81% of 1-RM and was not different between RT and RT + protein. There were no group-time interactions for strength, LM, FM, and biomarkers. Both groups significantly increased upper (+31 ± 18 kg) and lower (+19 ± 12 kg) body strength, LM (+0.9 ± 1.0 kg) and decreased FM (-0.5 ± 1.2 kg), and percent body fat (-1.0% ± 1.2%). Serum levels of IGF-1 significantly increased from baseline to 12 wk in both RT (102 ± 34 to 115 ± 33 ng·mL) and RT + protein (110 ± 40 to 119 ± 37 ng·mL); adiponectin and CRP did not change. Twelve weeks of RT at 65%-81% of 1-RM, 2 d·wk in BCS, was well tolerated and significantly improved strength, body composition, and IGF-1. Supplemental protein (40 g·d) did not induce a change in any variable. However, on the basis of food logs, reductions in total calories and dietary protein intake from whole foods resulted in only a net protein increase of 17 g·d for RT + protein, which may have influenced the results.

Variants of strength athletics (progression) and its application in training practice especially considering the speed of exercise performance

The aim of the study was to present the modifications of strength athletics, enabling the competitors to achieve maximal muscular stimulations, leading to the development of specific strength in large muscle groups. The application goal was also determined, involving presentation of exercise sets used in strength sports and combat sports, developing specific strength in major muscle groups, particularly considering the tempo of exercising in each training sub-periods. The reference sources are reviewed as well as the earlier publications, describing the basic modalities of strength athletics. The versions of this approach connected with methodical recommendations of Polish Strength Athletics School, established by Augustyn Dziedzic are also presented. Each variant of strength athletics is described in terms of its usefulness for developing maximal strength, anaerobic endurance, mastering motor habits (techniques), applying exercises which have a similar or a more complex structure than these previously applied and a fast tempo of exercising. Tempo variations are attributed to each sub-period of the training cycle, considering the frequency of application and exercise sets, aimed at the development of large muscle groups are presented. It is emphasized that strength athletics should be regarded as a set of approaches, which, regularly applied, allow considerable increases of maximal muscular strength, anaerobic endurance and mastering motor habits. It has been confirmed that the application of different modalities of exercising tempo not only enriches their resources, but also can increase muscular strength and power, significantly contributing to the improvement of athletic performance in combat sports.

Improving Power Output in Older Adults Utilizing Plyometrics in an AlterG Treadmill

In older adults, muscular strength has been shown to decline by up to 1-2% per year, and muscular power declines at an even higher rate. Plyometric training has shown benefits for increasing muscle force, power, and agility in adolescents and recreational adults; however, data on older adults is lacking. The AlterG treadmill allows for improved mobility, strength, and safety while improving functional capacity related to endurance, strength, and power. PURPOSE: To determine the effects of performing plyometrics in an AlterG treadmill on power output and functional strength in older adults when compared to traditional strength training. METHODS: Twenty-three subjects were randomized to a strength (SG) (n = 8), plyometric (PG) (n = 8), or control (CG) (n = 7). SG and PG exercised 3x/week for 8 weeks and CG performed no exercise. SG performed sets of 3x10 at 65-80% of one-repetition maximum (1RM) (estimated from 3-5RM) on the leg press (LP), leg extension (LE), and single leg lunge (LL). PG performed 3x10 in the squat jump, single leg bound, and power skipping at an intensity range of 65-80% body mass. Timed sit-to-stand and stair climb, estimated maximal muscular strength, and isokinetic power during leg flexion and extension were compared pre and post intervention. A 2 x 3 repeated measures ANOVA was used to determine differences between groups. Data was reported as percent change from baseline. RESULTS: Significant improvements occurred in the PG in the timed sit-to-stand (22.11 ± 8.48%, p = 0.013), timed stair climb (14.68 ± 6.28%, p = 0.002), and stair climb power (16.59 ± 9.07%, p < 0.001). PG and SG significantly increased their estimated 1RM in the LE and LL (p < 0.05). PG was significantly more powerful at all 3 velocities in both flexion and extension except at 60°/sec extension, ranging from 24.54 ± 19.94% to 85.74 ± 62.23% (p < 0.001). PG increased muscular strength similarly or better than SG without performing resistance training. CONCLUSIONS: Eight weeks of plyometrics in an AlterG treadmill improved functional strength and power in older adults, accomplished through performing exercise requiring less total work per exercise session. Results suggest that plyometrics, if modified and performed in a safe environment, can increase muscular strength and power and improve functional abilities in older adults.

중년 여성의 등속성 기능과 골밀도의 상관관계 분석

This study conducted a correlation analysis between body composition and isokinetic function, isokinetic function and bone density of middle-aged female and young female in order to prevent osteoporosis of middle-aged female.BR As for the result of correlation analysis between body composition and isokinetic function, the stretch of muscle power and age showed negative correlation(p.01)(p.05), and hamstring also showed negative correlation but the difference was insignificant. Maximum muscular strength of left flexor showed significant correlation with weight, body fat and basal metabolic rate(p.01), while the maximum muscular strength of right flexor showed significant correlation with weight(p.01), body fat and basal metabolic rate(p.05). Also, angular velocity 180°/sec left protractor muscle power weight, body fat, basal metabolic rate(p.01) and angular velocity 180°/sec right protractor muscle power showed significant correlation with weight(p.05). Left flexor muscle power showed significant correlation with weight, skeletal muscle mass, basal metabolic rate(p.01) while right side showed significant correlation with weight(p.01), skeletal muscle mass, basal metabolic rate(p.05). As for the correlation analysis of bone density and isokinetic function, left and right of angular velocity 180°/sec flexor muscle power showed significant correlation(p.05) with caput osis femoris. This indicates the aging of female reduces muscle strength, power and bone density. Therefore, health care for aging female is urgent, and in order to prevent decrease of bone density and bone health management, there is a need to conduct not only the extensor muscle exercise, but also the exercise program for muscle strength and power of hamstring.

The relationship between knee joint angle and knee flexor and extensor muscle strength.

[Purpose] The aim of this study was to determine a relationship between joint angle and muscular strength. In particular, this research investigated the differences in maximum muscular strength and average muscular strength at the knee-joint posture. [Subjects and Methods] The study subjects comprised eight female students in their 20s attending S University in Busan. None of the subjects had functional disabilities or had experienced damage to the lower extremities in terms of measurement of muscular strength. A BIODEX system III model (Biodex medical system, USA) was used to measure joint angles and muscular strength. The axis of the dynamometer was consistent with the axis of motion, and measurements were made at 25° and 67° to examine differences in maximum muscular strength according to joint angle. [Results] The maximum muscular strength both knee-joint extension value, at 67° and flexion value, at 25° the value was larger. The average muscular strength both knee-joint extension value, at 67° and flexion value, at 25° the value was larger. [Conclusion] The results of this study reveal that muscular strength does not reach maximum at particular range angles, such as the knee-joint resting posture angle or the knee-joint middle range angle. Rather, a stretched muscle is stronger than a contracted muscle. Therefore, it is considered that it will be necessary to study the effects of the joint change ratio on muscular strength on the basis of the maximum stretched muscle.

Muscular strength is associated with self-esteem in college men but not women.

Muscular strength is a well-known predictor of morbidity and mortality. Similarly, self-esteem is a predictor of health and well-being. The relationship between these two variables, however, is currently unknown. This study examined the cross-sectional relationship between maximal muscular strength (i.e. handgrip and one-repetition-maximum (1-RM) squat) and global self-esteem in 126 college students. Significant correlations were found between both measures of muscular strength and self-esteem. Further analyses revealed that these relationships were only significant for men. Based on these results, additional research is needed to further explore the relationship between muscular strength and self-esteem, especially in other demographic groups and longitudinally.

Effects of Creatine Supplementation on Athletic Performance and Body Composition after Complex Training

Complex training takes advantage of the phenomenon known as postactivation potentiation (PAP), which is an acute enhancement of jump performance following the heavy resistance exercise (HRE). Numerous of researches have shown fatigue mask the PAP effect in the early stage of recovery and the PAP is an individualized phenomenon. Creatine (Cr) supplementation plays an important role in short term energy metabolism of skeletal muscle. PURPOSE: To examine the effects of Cr supplementation on athletic performance and body composition after 4 weeks of complex training with optimal individual PAP time. METHOD: Thirty two explosive athletes conducted the tests of body composition, counter movement jump (CMJ), 30 m sprint and 1-repetition maximal (1 RM) half squat strength. A matched pair design was used to assign the subjects into creatine group (Cr gr.) or placebo group (Pla gr.) by their maximal muscular strength. Subjects consumed 5 g of Cr or methyl cellulose (Pla gr.) plus 5 g of glucose 4 times per day for 6 days. The 1 RM half squat strength was test again after the supplementation to calculate the weight of HRE in complex training. Meanwhile, subjects ingested 2 g of Cr (or methyl cellulose) plus 2 g of glucose per day till the end of study. Thereafter, complex training (6 sets, 5 RM of half squat and 8 jumps, with optimal individual PAP time for rest) was executed 3 times per week for 4 weeks. Body composition and athletic performance were tested after the training periods. RESULTS: After 4 weeks of training, time for 30 m sprint (Cr gr.: 4.31 ± 0.20 vs. 4.13 ± 0.17 s; Pla gr.: 4.26 ± 0.20 vs. 4.18 ± 0.15 s, p < .05) and 1 RM half squat strength (Cr gr.: 128.43 ±13.75 vs. 180.31 ±17.83 kg; Pla gr.: 127.18 ±17.50 vs. 165.31 ±14.19 kg, p < .05) were significantly improved in both groups. And the strength in Cr gr. was significantly higher than in Pla gr. There were no significant difference in height and peak power of CMJ, body mass, and body fat. CONCLUSION: Cr supplementation improved maximum muscle strength, but no effect on other athletic performance and body composition after 4 weeks of complex training with optimal individual PAP time for rest. Supported by Ministry of Science and Technology, Taiwan. (Grant No: MOST 102-2410-H-179-002)

The role of metaboreceptor on exercise in hyperthermic environment with college basketball players.

The objective of this study is to review physiological differences of college basketball players cardiovascular responses and group IV metaboreceptor interactions appearing post muscular ischemia exercise (PEMI) caused by a static handgrip exercise (SHE). The subjects were placed in a temperature and moisture stabilized indoor environment for 2 h in order to measure blood pressure. For the SHE, maximal voluntary contraction of arms with a relative strength of 50 % of the maximum muscular strength was put into isometric training for 2 min. After completing the exercises, cuffs worn on the arms of the subjects were pressurized up to 200 mmHg by applying PEMI to block the artery and vein. In this way, the cardiovascular responses created by SHE and PEMI were measured. Blood samples of subjects were collected from the vein of each upper arm before SHE and after PEMI to measure the metabolite hormone and catecholamine in the blood. Results from the measurements showed a significant decrease of blood pressure under high temperature environments compared to normal temperature environments. With respect to PEMI, increases in blood pressure under the high temperature environment were significantly lower compared to the normal temperature environment. In conclusion, this study revealed that college basketball players with good physical strength had higher sensitivities of arterial baroreceptor. However, blood pressure was not increased accordingly because the increase of cutaneous vasoconstriction due to stimuli of the metaboreceptor under a high temperature environment could not be compensated by arterial baroreflex due to the increase of total vascular conductance.

Effects of the optimal flexor/extensor ratio on G-tolerance.

[Purpose] The aim of this study was to examine the flexor/extensor ratio of the knee joints and compare it with the results of Korean Air Force students in G-tolerance test. [Subjects and Methods] The body composition of Korea Air Force students (n=77) was measured by an impedance method. A muscular function test was performed using a Humac Norm (USA) at angular speeds of 60°/sec and 240°/sec and an isokinetic muscular function test was also conducted. [Results] In the failed C and passing groups, muscle mass and fat percentages were significantly higher than those of students in the failed A group. The BMI of the failed C and passing groups were significantly higher than that of the failed A group. The group that passed had a significantly higher value of left knee 60°/sec flexion peak torque than the failed B group. Moreover, the total work of left knee extension of the failed C group and the passing group was significantly higher than that of the failed A group. The C group and the passing group had significantly higher values of the trunk 60°/sec flexor/extensor ratio than the failed A group, and the total work flexor/extensor ratio of the passing group was significantly higher than that of the failed A group. [Conclusions] Based on these results, balance the right and left knee flexor/extensor ratio, and a high flexor/extensor ratio of the trunk are required to endure a high G-tolerance test (+6G/30 sec). Moreover, an improvement in the maximum muscular strength is necessary to endure a situation of rapidly increasing acceleration in the early stage.

The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.

The Effects of Human Resistance Training on Muscular Strength

The aim of this study was to evaluate the impact of a resistance training program on basketball players that have been engaging in regular training processes for several years. The study participants (n=28) were Ataturk University basketball team players. The experimental group performed a 12-week, whole body resistance training. A device measured maximal power at thirty percent, forty percent, fifty percent and sixty percent of 1RM on the bench press for each subject. Both groups increased their maximal muscular power and strength, and the magnitude of increase was significantly different between them (P<0.01). The resistance training program induced less change than previously observed, probably because the subjects were involved in the training process for several years and were already well adapted. This study concluded muscle strength increased by 10.5 percent after 12 weeks of the resistance training program, but the power increasing amount was without growth and maturation and was more than 7.5 percent.

Effect of Nintendo Wii Fit Exercise Program to Health-Related Physical Fitness and Quality of Life among University Students

The purpose of this study is to investigate the effect of Nintendo Wii Fit exercise program to health-related physical fitness and quality of life among university students. Written, informed consent was obtained prior to the participation of the subjects. They participated in the exercise group (n = 25) and control group (n = 25) by themselves. Height, weight, body composition, BMI and WHR, blood pressure, HR and physical fitness (VO2max, muscular strength, muscular endurance, flexibility, etc.), and health-related quality of life (SF-36 questionnaire is used) were measured in the pre- and post-exercise program. In this result, we found interaction effects between the exercise group and control group in muscle mass. Further, the percentage of body fat, WHR, HR, maximum oxygen uptake (VO2 max), muscular strength, muscular endurance, and flexibility showed a significant difference in time between the two groups. Lastly, the physical functioning, body pain, and general health of SF-36 showed also statistical difference in duration between the two groups. The results in this paper suggested that the Nintendo Wii Fit exercise program during 12 weeks may influence the body composition, health-related physical fitness, and QOL of university students.

Efectos de un programa de entrenamiento de fuerza con pesas en nadadores con Síndrome de Down (Effects of Weight Resistance Training on Swimmers with Down Syndrome)

El objetivo de este estudio fue determinar el efecto de un programa de fuerza con pesas, sobre la fuerza máxima en nadadores con Síndrome de Down (SD). Participaron 7 nadadores con SD, 6 hombres y 1 mujer con edades de 23.14 años ± 4.59 y con 6.14 años ± 2.34 de práctica de deporte de la natación. Instrumentos: prueba de 1 repetición máxima (RM) para determinar la fuerza máxima muscular. Procedimiento: el estudio duró 10 semanas (2 semanas de línea de base, 6 semanas de tratamiento y 2 semanas para ver efectos de retención). Resultados: hubo cambios significativos positivos en la fuerza máxima de los músculos pectoral (F=5.768; p=0.006), dorsal (F= 26.770; p=7.45e-007), bíceps femoral (F= 32.530; p=1.76e-007), cuádriceps (F= 8.391; p=0.001), tríceps (F= 11.217; p=0.0002) y estas adaptaciones se mantuvieron, sin cambios significativos, durante dos semanas; mientras que el músculo del bíceps (F=4.145; p=0.021) se comportó de una manera diferente pues no tuvo adaptaciones significativas al programa. Palabra clave: Síndrome de Down. Natación. Entrenamiento de fuerza.Abstract: The objective of this study was to determine the effect of weight resistance training on strength in swimmers with Down Syndrome (DS). Seven swimmers with DS participated in the study: 6 men and 1 woman, 23.14 years of age ± 4.59 and with 6.14 years ± 2.34 years of swimming. Instruments: One repetition maximum (RM) test to determine the individual’s maximum muscular strength. Procedure: the study was conducted for 10 weeks (2 weeks at baseline, 6 weeks of treatment and 2 weeks to see the effects of retention). Results: significantly positive changes were detected in the maximum strength of pectoral muscles (F=5.768; p=0.006), dorsal muscles (F = 26.770; p=7.45e-007), femoral biceps (F = 32.530; p=1.76e-007), quadriceps (F = 8.391; p=0.001), triceps (F = 11.217; p=0.0002) and these adjustments were maintained with no significant changes for two weeks, while the biceps muscle (F=4.145; p=0.021) behaved differently since it suffered no significant adjustments during the program.Key words: Down Syndrome, swimming, weight resistance training.