Isokinetic trunk flexion–extension protocol to assess trunk muscle strength and endurance: Reliability,learning effect,and sex differences

PurposeThe purpose of this study was to examine the reliability and the learning effect of an isokinetic trunk flexion–extension protocol designed to simultaneously assess trunk muscle strength and endurance. In addition, the effect of the participants' sex on the reliability data was examined.MethodsFifty-seven healthy and physically active young men (n = 28) and women (n = 29) performed the isokinetic protocol 5 times, separated by a week between each of the first 4 sessions and by a month between the last 2 sessions. The protocol consisted of performing 4 trials of 15 maximum flexion–extension concentric exertions at 120°/s (range of trunk motion = 50°). The absolute and relative peak torque and total work were calculated to assess trunk flexion and extension strength. In addition, endurance ratio, modified endurance ratio, fatigue final ratio, recovery ratio, and modified recovery ratio variables were used for the assessment of trunk muscle endurance in both directions.ResultsRegarding the absolute reliability, no relevant changes were found between paired-comparison sessions for most strength and endurance variables, except for total work and relative total work variables in the flexion movement in both sexes. In addition, the typical error of the isokinetic variables was lower than 10% in both males and females, and minimum detectable changes ranged from 7% to 20%, with a tendency to be higher in females and in endurance variables. The strength variables showed high-to-excellent intraclass correlation coefficients (ICCs; >0.74); however, for the endurance variables only the endurance ratio and the modified endurance ratio obtained moderate-to-high ICC values (0.57 < ICC < 0.82). In addition, the analysis of the variance reported no significant differences between consecutive pairs of sessions for most variables in both sexes.ConclusionOverall, these findings provide clinicians, trainers, and researchers with a 10-min single-session protocol to perform a reliable muscle strength and endurance evaluation of trunk flexor and extensor muscles, all within the same protocol.     

Acute neuromuscular and metabolic responses to combined strength and endurance loadings: the “order effect” in recreationally endurance trained runners

Abstract

The study examined the acute neuromuscular and metabolic responses and recovery (24 and 48 h) to combined strength and endurance sessions (SEs). Recreationally endurance trained men (n = 12) and women (n = 10) performed: endurance running followed immediately by a strength loading (combined endurance and strength session (ES)) and the reverse order (SE). Maximal strength (MVC), countermovement jump height (CMJ), and creatine kinase activity were measured pre-, mid-, post-loading and at 24 and 48 h of recovery. MVC and CMJ were decreased (P < 0.05) at post-ES and SE sessions in men. Only MVC decreased in ES and SE women (P < 0.05). During recovery, no order differences in MVC were observed between sessions in men, but MVC and CMJ remained decreased. During recovery in women, a delayed decrease in CMJ was observed in ES but not in SE (P < 0.01), while MVC returned to baseline at 24 h. Creatine kinase increased (P < 0.05) during both ES and SE and peaked in all groups at 24 h. The present combined ES and SE sessions induced greater neuromuscular fatigue at post in men than in women. The delayed fatigue response in ES women may be an order effect related to muscle damage.     

Muscle Fiber Type Composition and Knee Extension Isometric Strength Fatigue Patterns in Power- and Endurance-Trained Males

Abstract

Muscle fiber type composition in the vastus lateralis and knee extension isometric strength fatigue patterns were assessed in eight endurance-trained and eight power-trained males. Two different 25-trial isometric contraction exercise regimens were administered: a 10-second contraction, 5-second intertrial rest condition designed to induce a fast rate of fatigue and a 10-second contraction, 20-second intertrial rest condition designed to induce a slower rate of fatigue. The power group fatigued almost four times faster than the endurance group in the 10:5 exercise condition. In the 10:20 exercise condition, the endurance group showed no fatigue pattern while the power group had a significant strength decrement of 32%. In both exercise conditions, the power group exhibited more complex fatigue patterns in terms of statistically significant trend components. Maximum isometric strength correlated positively with slow twitch (ST) percent number in power (r = .80) and endurance (r = .48) groups, but negatively with linear trend coefficients in endurance (r = -.62) and power (r = -.80) groups. Maximum isometric strength also correlated higher with fatigue curve trend coefficients than did muscle fiber type composition. Thus, a faster rate of fatigue was associated with higher maximum isometric strength and with higher ST percent number and area. Since maximum isometric strength correlated with body weight (r = .86 for groups combined), both maximum isometric strength and muscle mass appear to be more important determinants of knee extension isometric strength fatigue patterns than muscle fiber type composition.     

Effects of different types of exercise on muscle mass,strength, function and well-being in elderly

Abstract

Poor muscle strength and physical function have been associated with higher risk of hospitalisation and lower well-being among the elderly. Physical training increases muscle strength, endurance and physical function as well as psychological outcomes. Exercise among older adults is often used to improve these variables, but few have compared the effects of different types of training in parallel independent groups. Thus, the aim of the present study was to investigate the effect of three different types of training on body composition, muscle strength, physical function and well-being in the elderly. A total of 118 community-dwelling older adults (mean age 74.3, s=4.6 years, 68% women) completed a 13-week randomised controlled exercise-trial involving four groups: traditional strength training (STG), functional strength training (FTG), endurance training (ETG) and control (CON). Stair climb with load improved more in FTG than CON (P<0.05), and the two strength groups performed better in the functional upper body test (P<0.05). STG increased strength more than CON in all exercises (P<0.001), while FTG increased strength more than CON in the chest press, shoulder press and knee extension (P<0.05). Lean body mass (LBM) increased in all training groups, which differed significantly from CON (P<0.05). ETG decreased their fat mass compared to CON (P<0.001). The only significant effect on well-being indices was improved life satisfaction in FTG at week 5 (P<0.05). We also observed significant correlations between change in some of the functional tests and change in positive affect.

All three types of training can enhance physical capacity. Functional strength training can be a cost effective form of training in terms of less demand for instructors and equipment and could be an effective way to improve physical function, strength and indices of well-being in the elderly.     

Age-Related Differences in Muscular Strength and Muscular Endurance among Female Masters Swimmers

Abstract

The purpose of this study was to examine age-related differences in muscular strength and muscular endurance among 73 female masters swimmers aged 24 to 71 years. Each subject was assessed on measures of body size, grip strength, peak isokinetic torque of shoulder and knee flexion and extension, and endurance of shoulder and knee movements. Although swim training appears to have resulted in higher strength values for these swimmers than for less active women, an age-related decline in muscular strength values was nevertheless apparent. The results fail to reveal a similar age-related trend for muscular endurance, suggesting that swim training influences muscular endurance more than muscular strength among adult women.     

Low-intensity electrical muscle stimulation induces significant increases in muscle strength and cardiorespiratory fitness

The aim of this study was to investigate the effect of low-intensity exercise training using belt electrode skeletal muscle electrical stimulation on muscle strength and cardiorespiratory fitness in healthy subjects. Nineteen healthy subjects were allocated into control or intervention groups; in both groups the participants kept regular physical activity while the intervention group underwent 30 min B-SES training at 3–4 METs for four weeks. Knee extensor muscle strength and cardiorespiratory endurance during incremental exercise test were measured at baseline and after four weeks for all participants. The relative change of knee extensor muscle strength in the intervention group was significantly higher than control group (p?p?相似文献   

Do kinaesthetic tapes affect plantarflexor muscle performance?

Abstract

This study aimed to examine the effects of application of kinaesthetic tapes on plantarflexor muscle performance. We hypothesised that taping of the triceps surae muscle would improve plantarflexor muscle strength and endurance with no significant effect on drop jump performance. Using a repeated-measures design, all performance measures were obtained in 24 volunteers on two separate occasions: without tapes and after application of kinaesthetic tapes. Performance tests included measurements of isometric plantarflexor muscle strength and the associated electromyographic activity of the gastrocnemius muscle, an isokinetic fatigue resistance test (30 contractions at 180° · s^?1) and assessments of drop jump performance. The taping-intervention was associated with an increase in gastrocnemius electromyographic activity. However, significant increases in isometric strength were only found at fully dorsiflexed ankle positions (+12% at ?20°). Strength gains were negatively correlated to baseline strength (r = ?.58). The intervention did not affect the results of the isokinetic fatigue and drop jump tests. The application of kinaesthetic tapes over the triceps surae muscle promotes an increase in isometric strength and gastrocnemius muscle activity. Our data suggest that these effects are joint-angle dependent and more prominent in weaker individuals. By contrast, the taping-intervention improves neither drop jump performance nor muscular endurance.     

The Relationship Between Measures of Physical Growth and Gross Motor Performance of Primary-Grade School Children

Abstract

The purpose of this study was twofold: (1) to investigate the relationship between strength and achievement in physical education among 200 college women by comparing grip strength with grades in the instructional physical education courses and (2) to compare the results obtained on college women with those of college men in the study by Tinkle and Montoye reported in this issue of the Research Quarterly. A table of random numbers was used to secure the sample. The results indicated that grip strength among college women was significantly related to achievement in physical education instructional courses as measured by grades. Also, grip strength was found to be directly related to and probably dependent upon body weight and only indirectly related to height in college women. The relationship between grades in physical education and grip strength among college women substantiates the results of the college men's study.     

Creatine co-ingestion with carbohydrate or cinnamon extract provides no added benefit to anaerobic performance

The insulin response following carbohydrate ingestion enhances creatine transport into muscle. Cinnamon extract is promoted to have insulin-like effects, therefore this study examined if creatine co-ingestion with carbohydrates or cinnamon extract improved anaerobic capacity, muscular strength, and muscular endurance. Active young males (n?=?25; 23.7?±?2.5?y) were stratified into 3 groups: (1) creatine only (CRE); (2) creatine+ 70?g carbohydrate (CHO); or (3) creatine+ 500?mg cinnamon extract (CIN), based on anaerobic capacity (peak power·kg^?1) and muscular strength at baseline. Three weeks of supplementation consisted of a 5?d loading phase (20?g/d) and a 16?d maintenance phase (5?g/d). Pre- and post-supplementation measures included a 30-s Wingate and a 30-s maximal running test (on a self-propelled treadmill) for anaerobic capacity. Muscular strength was measured as the one-repetition maximum 1-RM for chest, back, quadriceps, hamstrings, and leg press. Additional sets of the number of repetitions performed at 60% 1-RM until fatigue measured muscular endurance. All three groups significantly improved Wingate relative peak power (CRE: 15.4% P?=?.004; CHO: 14.6% P?=?.004; CIN: 15.7%, P?=?.003), and muscular strength for chest (CRE: 6.6% P?P?P?P?P?P?P?=?.013; CHO: 10.0% P?=?.007; CIN: 17.3% P?P?=?.021) and CIN (15.5%, P?相似文献   

The improvement in walking speed induced by resistance training is associated with increased muscular strength but not skeletal muscle mass in older women

Objective: The purpose of the present study was to analyze whether improvements in fast walking speed induced by resistance training (RT) are associated with changes in body composition, muscle quality, and muscular strength in older women. Methods: Twenty-three healthy older women (69.6?±?6.4 years, 64.95?±?12.9?kg, 1.55?±?0.07?m, 27.06?±?4.6?kg/m²) performed a RT program for 8 weeks consisting of 8 exercises for the whole body, 3 sets of 10–15 repetitions maximum, 3 times a week. Anthropometric, body composition (fat-free mass [FFM], skeletal muscle mass [SMM], legs lean soft tissue [LLST], fat mass), knee extension muscular strength (KE1RM), muscle quality index (MQI [KE1RM/LLST]), and 10-meter walking test (10-MWT) were performed before and after the intervention. Results: Significant (P?<?.05) changes were observed from pre- to post-training for FFM (+1.6%), MQI (+7.2%), SMM (+2.4%), LLST (+1.8%), KE1RM (+8.6%), fat mass (?1.4%), and time to perform 10-MWT (?3.7%). The percentage change in 10-MWT was significantly associated with percentage change in MQI (r?=??0.46, P?=?.04) and KE1RM (r?=??0.45, P?=?.04), however not associated percentage of changes in SMM (r?=?0.01, P?=?.97), LLST (r?=??0.22, P?=?.33), and body fat (r?=?0.10, P?=?.66). Conclusion: We conclude that the improvement in the 10-MWT after an 8-week RT program is associated with increases in lower limb muscular strength and muscle quality, but not with muscle mass or body fat changes in older women.     

Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners

Abstract

The purpose of this study was to assess the effects of heavy resistance, explosive resistance, and muscle endurance training on neuromuscular, endurance, and high-intensity running performance in recreational endurance runners. Twenty-seven male runners were divided into one of three groups: heavy resistance, explosive resistance or muscle endurance training. After 6 weeks of preparatory training, the groups underwent an 8-week resistance training programme as a supplement to endurance training. Before and after the 8-week training period, maximal strength (one-repetition maximum), electromyographic activity of the leg extensors, countermovement jump height, maximal speed in the maximal anaerobic running test, maximal endurance performance, maximal oxygen uptake ([Vdot]O_2max), and running economy were assessed. Maximal strength improved in the heavy (P = 0.034, effect size ES = 0.38) and explosive resistance training groups (P = 0.003, ES = 0.67) with increases in leg muscle activation (heavy: P = 0.032, ES = 0.38; explosive: P = 0.002, ES = 0.77). Only the heavy resistance training group improved maximal running speed in the maximal anaerobic running test (P = 0.012, ES = 0.52) and jump height (P = 0.006, ES = 0.59). Maximal endurance running performance was improved in all groups (heavy: P = 0.005, ES = 0.56; explosive: P = 0.034, ES = 0.39; muscle endurance: P = 0.001, ES = 0.94), with small though not statistically significant improvements in [Vdot]O_2max (heavy: ES = 0.08; explosive: ES = 0.29; muscle endurance: ES = 0.65) and running economy (ES in all groups < 0.08). All three modes of strength training used concurrently with endurance training were effective in improving treadmill running endurance performance. However, both heavy and explosive strength training were beneficial in improving neuromuscular characteristics, and heavy resistance training in particular contributed to improvements in high-intensity running characteristics. Thus, endurance runners should include heavy resistance training in their training programmes to enhance endurance performance, such as improving sprinting ability at the end of a race.     

Beneficial Effects of Inspiratory Muscle Training Combined With Multicomponent Training in Elderly Active Women

ABSTRACT

Purpose: This study aims to analyze changes in Maximum Inspiratory Pressure (MIP), lung function, cardiorespiratory fitness, and blood pressure, in 10 healthy active elderly women, following 7 weeks of inspiratory muscle training (IMT) combined with a multicomponent training program (MCTP). The association among these health parameters, their changes after training (deltas), and the influence of MIP at baseline (MIP_pre) are also considered. Methods: IMT involved 30 inspirations at 50% of the MIP, twice daily, 7 days a week, while MCTP was 1 hr, twice a week. MIP, lung function (FVC, FEV₁, FEV₁/FVC, FEF_25-75%, PEF), 6MWT, and blood pressure (SBP, DBP), jointly with body composition, were assessed before and after the intervention. Results: Seven weeks were enough to improved MIP (p = .019; d = 1.397), 6MWT (p = .012; d = .832), SBP (p = .003; d = 1.035) and DBP (p = .024; d = .848). Despite the high physical fitness (VO₂ peak: M = 23.38, SD = 3.39 ml·min·Kg^?1), MIP_pre was low (M = 39.00, SD = 7.63 cmH₂O) and displayed a significant negative correlation with ΔMIP_pre-post (r = ?.821; p < .004), showing that women who started the intervention with lower MIP achieved higher improvements in inspiratory muscle strength after training. Conclusions: No significant changes in spirometric parameters may signal that lung function is independent of early improvements in inspiratory muscles and cardiorespiratory fitness. Absence of correlation between physical fitness and respiratory outcomes suggests that being fit does not ensure cardiorespiratory health in active elderly women, so IMT might be beneficial and should supplement the MCTP in this population.     

A Test of Activation as a General Factor in Strength Performance

Abstract

A test was made of the general activation concept as it relates to strength performance. No difference in grip strength was found between an experimental group (N = 35), who performed maximal leg strength exercises between grip trials (in an attempt to raise their level of activation through induced muscular tension), and a control group (N = 35) who read between grip trials. Also, there was no difference in grip strength performance over trials for both groups. Intercorrelations of strength scores between limbs for the experimental group showed more specificity than generality. While these results fail to support a generalized activation effect in the static strength performance context, they do provide additional evidence of neuromuscular specificity in motor ability.     

Baumgartner's Modified Pull-Up Test For Male and Female Elementary School Aged Children

Abstract

Nineteen college men and women (aged 18–23 yrs, × = 21.1) were studied to ascertain the force-time components of a rapid maximal voluntary isometric contraction (MVC) for ankle dorsiflexors, knee extensors, elbow flexors, wrist flexors and hand grip. Standardized isometric strength testing protocol was used. After a practice period subjects were instructed to make an MVC without jerking and as quickly as possible, for each of the muscle actions noted above. Force readings were taken from a load cell assembly through an analogue-to-digital converter and analyzed to yield time values for MVC, 3/4 MVC, 1/2 MVC, and 1/4 MVC. The results indicated significant differences (p < .01) between the responses of the men and women, with the women reaching full MVC more rapidly than the men. Also, there were significant differences among the five muscle groups tested, with the wrist flexor muscle group developing MVC most quickly, while the knee extensors took the longest time to full MVC. Based upon these data it may be concluded that the time to full MVC differs between men and women, and also that the time to full MVC differs among the five muscle groups tested in this experiment.     

Effect of resistance training with different frequencies and subsequent detraining on muscle mass and appendicular lean soft tissue,IGF-1, and testosterone in older women

Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin-like growth factor 1 (IGF-1), testosterone, and their changes with detraining in older women. Methods: Forty-five physically independent older women (≥ 60?years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12?weeks (8 exercises, 1 set of 10–15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF-1, testosterone, and dietary intake were measured at pre-training, post-training, and after detraining (12?weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post-training (G2X?=?+5.5% and G3X?=?+5.8%, P?P?P?Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF-1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community-dwelling older women and may not be generalized to other populations.     

Socioeconomic status and physical fitness in youth: Findings from the NHANES National Youth Fitness Survey

ABSTRACT

This study examined the associations between socioeconomic status (SES) and musculoskeletal (MSF) and cardiorespiratory fitness (CRF) in youth. The sample consisted of boys and girls between 3-15 years. SES was categorized utilizing family-income-to-poverty ratio (FIPR). All analyses were standardized for age and sex. For each test of physical fitness, SES was used to estimate mean fitness test percentile and 95% confidence intervals, controlling for race/ethnicity and physical activity. Odds ratios were calculated for the likelihood of having low fitness by SES category. In general, the high SES group had a better composite MSF, body composition, and CRF profiles than low and moderate SES groups. Statistically significant differences were identified for relative grip strength, plank, body mass index, and cardiovascular endurance time (all p < 0.05). Additionally, the odds of low/poor MSF fitness were 1.7 and 1.6 times higher in the low and moderate SES groups (respectively) compared to the children from high SES families. The moderate SES group had an odds of poor CRF 1.6 times higher than the high SES group as well. Children and adolescents from high SES families tend to have higher mean fitness and were less likely to have low/poor fitness.     

A cross-sectional study on the deprivation and sex differences in health-related fitness measures in school children

ABSTRACT

This study aimed to investigate deprivation and sex differences in selected health-relatedfitness measures in 9-12-year-old children. Data were captured on 3,407 children (49.3% boys; aged 10.5 ± 0.6 years). Cardiorespiratory fitness(20 m multistage shuttle run test; 20 m MSRT), muscular strength (handgrip strength) and body mass index (BMI) were measured. Welsh Index of Multiple Deprivation (WIMD) scores were used to make quintile groups. A two-way Analysis of Variance examined differences in BMI z-score by sex and WIMD quintiles. Two-wayAnalysis of Covariances investigated the effect of sex and WIMD quintiles on grip strength and shuttles achieved in 20 m MSRT, adjusting for BMI z-score and maturation, repectively. Independent of sex, children in the middle quintile had a significantly higher mean BMI z-score (p = 0.029) than their least deprived counterparts. There was a significant increase in grip strength (p = 0.005) and20 m MSRT (boys p < 0.001; girls p = 0.028) between most and least deprived quintiles. Significant differences in 20 m MSRT score were more apparent with decreases in deprivation in boys.Overall, inequalities exist in health-related fitness by sex and deprivation. These results can be used to inform focused services to improve current and future health.     

ACTN3 R577X polymorphism and performance phenotypes in young Chinese male soldiers

Abstract

Alpha-actinin-3 (ACTN3) is absent in 18% of healthy Caucasian individuals owing to homozygosity for a premature stop codon (X) at amino acid 577 (rs1815739). Previous studies have shown a strong association between ACTN3 genotype and human athletic performance. In a study of 452 young Chinese male soldiers, we examined the distribution of ACTN3 genotypes and alleles and analysed the association between ACTN3 genotypes and athletic performance. We found that the frequencies of the ACTN3 R577X genotype (RR 39.8%, RX 43.4%, and XX 16.8%) and R577X allele (R 61.5%, X 38.5%) in young Chinese males were not significantly different from those in Caucasians. We only observed a significant association (P = 0.025) between ACTN3 R577X genotypes and grip strength. Participants with the XX genotype displayed significantly lower handgrip strength than individuals with the RR genotype (P = 0.021), but the difference between XX and RX means (P = 0.258) and that between RR and RX means (P = 0.42) was not significant. We did not observe a strong association between the ACTN3 R577X genotypes and sprint phenotypes or endurance phenotypes. In conclusion, our results indicate that the ACTN3 R577X polymorphism is most strongly associated with grip strength in young Chinese male soldiers.