Action potential amplitude as a noninvasive indicator of motor unit-specific hypertrophy

Skeletal muscle fibers hypertrophy in response to strength training, with type II fibers generally demonstrating the greatest plasticity in regards to cross-sectional area (CSA). However, assessing fiber type-specific CSA in humans requires invasive muscle biopsies. With advancements in the decomposition of surface electromyographic (sEMG) signals recorded using multichannel electrode arrays, the firing properties of individual motor units (MUs) can now be detected noninvasively. Since action potential amplitude (APSIZE) has a documented relationship with muscle fiber size, as well as with its parent MU's recruitment threshold (RT) force, our purpose was to examine if MU APSIZE, as a function of its RT (i.e., the size principle), could potentially be used as a longitudinal indicator of MU-specific hypertrophy. By decomposing the sEMG signals from the vastus lateralis muscle of 10 subjects during maximal voluntary knee extensions, we noninvasively assessed the relationship between MU APSIZE and RT before and immediately after an 8-wk strength training intervention. In addition to significant increases in muscle size and strength (P < 0.02), our data show that training elicited an increase in MU APSIZE of high-threshold MUs. Additionally, a large portion of the variance (83.6%) in the change in each individual's relationship between MU APSIZE and RT was explained by training-induced changes in whole muscle CSA (obtained via ultrasonography). Our findings suggest that the noninvasive, electrophysiological assessment of longitudinal changes to MU APSIZE appears to reflect hypertrophy specific to MUs across the RT continuum.

Effects of Loaded Squat Exercise with and without Application of Superimposed EMS on Physical Performance

The aim of the present study was to investigate the effects of a multiple set squat exercise training intervention with superimposed electromyostimulation (EMS) on strength and power, sprint and jump performance. Twenty athletes from different disciplines participated and were divided into two groups: strength training (S) or strength training with superimposed EMS (S+E). Both groups completed the same training program twice a week over a six week period consisting of four sets of the 10 repetition maximum of back squats. Additionally, the S+E group had EMS superimposed to the squat exercise with simultaneous stimulation of leg and trunk muscles. EMS intensity was adjusted to 70% of individual pain threshold to ensure dynamic movement. Strength and power of different muscle groups, sprint, and vertical jump performance were assessed one week before (pre), one week after (post) and three weeks (re) following the training period. Both groups showed improvements in leg press strength and power, countermovement and squat jump performance and pendulum sprint (p < 0.05), with no changes for linear sprint. Differences between groups were only evident at the leg curl machine with greater improvements for the S+E group (p < 0.05). Common squat exercise training and squat exercise with superimposed EMS improves maximum strength and power, as well as jumping abilities in athletes from different disciplines. The greater improvements in strength performance of leg curl muscles caused by superimposed EMS with improvements in strength of antagonistic hamstrings in the S+E group are suggesting the potential of EMS to unloaded (antagonistic) muscle groups. Key pointsSimilar strength adaptations occurred after a 6 week 10 RM back squat exercise program with superimposed EMS (S+E) and 10 RM back squat exercise (S) alone.Specific adaptations for S+E at the leg curl muscles were evident.S and S+E improved SJ, CMJ and pendulum sprint performance.No improvement occurred in linear sprint performance.

The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance

The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM) strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT) or a non-exercising control group (CTL). The IRT group underwent 6 weeks of training (2 days per week) consisting of 5 sets of 6-10 repetitions at 75-85% of subjects' peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s(-1) [3-sec concentric (CON) and 3-sec eccentric (ECC) phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey's post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg), 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg), and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions) increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women. Key pointsMultiple-joint isokinetic resistance training increases dynamic maximal muscular strength, local muscular endurance, and maximal isokinetic strength in women.Multiple-joint isokinetic resistance training increased 1RM strength in the bench press (by 10.2%), bent-over barbell row (by 11.2%), and maximal modified push-up performance (by 28.6%) indicating a carryover of training effects to dynamic exercise performance.The carryover effects may be attractive to strength training and conditioning professionals seeking to include alternative modalities such as multiple-joint isokinetic dynamometers to resistance training programs.

Volume-equated high- and low-repetition daily undulating programming strategies produce similar hypertrophy and strength adaptations

The overarching aim of this study was to compare volume-equated high-repetition daily undulating periodization (DUPHR) versus a low-repetition daily undulating periodization (DUPLR) program for muscle performance. Sixteen college-aged (23 ± 3 years) resistance-trained males were counterbalanced into 2 groups: (i) DUPHR (n = 8), with a weekly training order of 12 repetitions (Day 1), 10 repetitions (Day 2), and 8 repetitions (Day 3); and (ii) DUPLR (n = 8), with a weekly training order of 6 repetitions (Day 1), 4 repetitions (Day 2), and 2 repetitions (Day 3). Both groups trained 3 times/week for 8 weeks on nonconsecutive days, with pre- and post-training testing during weeks 1 and 8. Participants performed only squat and bench press exercises each session. Changes in one-repetition maximum (1RM) strength, muscle thickness (MT), and muscular endurance (ME) were assessed. Both groups significantly increased 1RM strength for both squat and bench press (p < 0.01), and no group differences existed (p > 0.05). Similarly, both groups experienced significant increases in chest, lateral quadriceps distal, and anterior quadriceps MT (p < 0.05), but no change was present in either group for lateral quadriceps mid MT (p < 0.05). No group differences were discovered for changes in MT (p > 0.05). ME did not significantly change in the squat or bench press for either group (p > 0.05); however, for squat ME, a moderate effect size was observed for DUPHR (0.57) versus a trivial effect size for DUPLR (0.17). Our findings suggest that in previously trained males, training volume is a significant contributor to strength and hypertrophy adaptations, which occur independently of specific repetition ranges.

The descriptive epidemiology of total physical activity, muscle-strengthening exercises and sedentary behaviour among Australian adults--results from the National Nutrition and Physical Activity Survey

BACKGROUND

The current Australia's Physical Activity and Sedentary Behaviour Guidelines recommend that adults engage in regular moderate-to-vigorous-intensity physical activity (MVPA) and strength training (ST), and minimise time spent in sedentary behaviours (SB). However, evidence about the specific individual and concurrent distribution of these behaviours in Australia is scarce. Therefore, the aim of this study was to determine the prevalence and sociodemographic correlates of MVPA, ST and SB in a national-representative sample of Australian adults.

METHODS

Data were collected using face-to-face interviews, as part of the National Nutrition and Physical Activity Survey 2011-12. The population-weighted proportions meeting the MVPA (≥ 150 min/week), ST (≥ 2 sessions/week) and combined MVPA-ST guidelines, and proportions classified as having 'low levels of SB' (< 480 min/day) were calculated, and their associations with selected sociodemographic and health-related variables were assessed using multiple logistic regression analyses. This was also done for those at potentially 'high-risk', defined as insufficient MVPA-ST and 'high-sedentary' behaviour.

RESULTS

Out of 9345 participants (response rate = 77.0 %), aged 18-85 years, 52.6 % (95 % CI: 51.2 %-54.0 %), 18.6 % (95 % CI: 17.5 %-19.7 %) and 15.0 % (95 % CI: 13.9 %-16.1 %) met the MVPA, ST and combined MVPA-ST guidelines, respectively. Female gender, older age, low/medium education, poorer self-rated health, being classified as underweight or obese, and being a current smoker were independently associated with lower odds of meeting the MVPA, ST and combined MVPA-ST guidelines. A total of 78.9 % (95 % CI: 77.9 %-80.0 %) were classified as having low levels of SB. Females, older adults and those with lower education were more likely to report lower levels of SB, whilst those with poor self-rated health and obese individuals were less likely to report lower levels of SB (i.e. SB = ≥ 480 min/day). A total of 8.9 % (95 % CI: 8.1 %-9.6 %) were categorised as individuals at potentially 'high-risk'. Those with poorer self-rated health, obese individuals, those aged 25-44, and current smokers were more likely to be in the 'high risk' group.

CONCLUSIONS

The large majority of Australian adults do not meet the full physical activity guidelines and/or report excessive SB. Our results call for public health interventions to reduce physical inactivity and SB in Australia, particularly among the subgroups at the highest risk of these unhealthy behaviours.

Translating Strong for Life Into the Community Care Program: Lessons Learned

We used a randomized controlled trial to test the implementation of Strong for Life (SFL), a resistance exercise intervention, using 32 home care aides (HCAs) as exercise leaders with their 42 homebound older adult clients enrolled in the Community Care Program, a Medicaid 1915(c) waiver program. Mixed-methods were used to analyze outcomes of program satisfaction rates, training session evaluations, program fidelity, and job descriptive index scores. Results indicate that it is feasible for HCAs to implement SFL safely with clients. Participants viewed SFL as highly satisfactory and HCAs were able to adapt SFL for their clients. HCAs have high job satisfaction, and leading SFL enhances work achievement and pride. Our results show it is possible to train HCAs to implement SFL with their clients in addition to providing usual care services, participation positively affects both care partners, and this is a feasible and practical delivery model to provide exercise for adults receiving home- and community-based services.

Oxygen Consumption and Substrate Utilization During and After Resistance Exercises Performed with Different Muscle Mass

This study investigated the energy expenditure (EE) and substrate utilization reflected by the respiratory-exchange ratio (RER) during and after resistance exercises performed with different muscle mass. Ten male volunteers (mean±SD; 26±4yr, 179±6cm, 77±8kg) performed multiple sets of the horizontal leg press (LP) and chest fly (CF) (5 sets of 10 repetitions with 15 repetition-maximum, 1-minute between-set intervals) in a counterbalanced design. Oxygen uptake and carbon dioxide production were measured during 40 minutes of resting; resistance exercise protocols (sets and intervals); 90 minutes of post-exercise recovery. Total fat and carbohydrate oxidation rates were calculated according to the non-protein respiratory quotient. Both exercise conditions elicited net excess post-exercise oxygen consumption (EPOC) of similar duration (approximately 40min). The EPOC magnitude at 40 minutes was greater after LP than after CF (7.36±1.10L vs. 4.73±0.99L; P<0.001). The RER was higher in LP (1.30±0.04) than CF (1.16±0.05, P=0.0003) during exercise. During recovery the RER was similar in LP and CF (P>0.05) and lower than pre-exercise (Pre-exercise=0.78±0.04 vs. CF40min=0.74±0.04; CF90min=0.68±0.02 and LP50min=0.73±0.06; LP90min=0.65±0.04, P<0.05). However, fat oxidation after LP was greater than CF between 30-90 minutes of recovery (mean total fat oxidation: LP=10.9 g vs. CF=8.4 g; P<0.01). The increases of EE and fat oxidation during post-exercise recovery were greater after multiple sets of resistance exercises performed with larger muscle mass than smaller muscle mass. This finding has practical implications for resistance training designed as part of weight management programs.

Corticomotor Excitability is Increased Following an Acute Bout of Blood Flow Restriction Resistance Exercise

We used transcranial magnetic stimulation (TMS) to investigate whether an acute bout of resistance exercise with blood flow restriction (BFR) stimulated changes in corticomotor excitability (motor evoked potential, MEP) and short-interval intracortical inhibition (SICI), and compared the responses to two traditional resistance exercise methods. Ten males completed four unilateral elbow flexion exercise trials in a balanced, randomized crossover design: (1) heavy-load (HL: 80% one-repetition maximum [1-RM]); (2) light-load (LL; 20% 1-RM) and two other light-load trials with BFR applied; (3) continuously at 80% resting systolic blood pressure (BFR-C); or (4) intermittently at 130% resting systolic blood pressure (BFR-I). MEP amplitude and SICI were measured using TMS at baseline, and at four time-points over a 60 min post-exercise period. MEP amplitude increased rapidly (within 5 min post-exercise) for BFR-C and remained elevated for 60 min post-exercise compared with all other trials. MEP amplitudes increased for up to 20 and 40 min for LL and BFR-I, respectively. These findings provide evidence that BFR resistance exercise can modulate corticomotor excitability, possibly due to altered sensory feedback via group III and IV afferents. This response may be an acute indication of neuromuscular adaptations that underpin changes in muscle strength following a BFR resistance training programme.

The one repetition maximum test and the sit-to-stand test in the assessment of a specific pulmonary rehabilitation program on peripheral muscle strength in COPD patients

BACKGROUND

Individuals with COPD may present reduced peripheral muscle strength, leading to impaired mobility. Comprehensive pulmonary rehabilitation (PR) should include strength training, in particular to lower limbs. Furthermore, simple tools for the assessment of peripheral muscle performance are required.

OBJECTIVES

To assess the peripheral muscle performance of COPD patients by the sit-to-stand test (STST), as compared to the one-repetition maximum (1-RM), considered as the gold standard for assessing muscle strength in non-laboratory situations, and to evaluate the responsiveness of STST to a PR program.

METHODS

Sixty moderate-to-severe COPD inpatients were randomly included into either the specific strength training group or into the usual PR program group. Patients were assessed on a 30-second STST and 1-minute STST, 1-RM, and 6-minute walking test (6MWT), before and after PR. Bland-Altman plots were used to evaluate the agreement between 1-RM and STST.

RESULTS

The two groups were not different at baseline. In all patients, 1-RM was significantly related to the 30-second STST (r=0.48, P<0.001) and to 1-minute STST (r=0.36, P=0.005). The 30-second STST was better tolerated in terms of the perceived fatigue (P=0.002) and less time consuming (P<0.001) test. In the specific strength training group significant improvements were observed in the 30-second STST (P<0.001), 1-minute STST (P=0.005), 1-RM (P<0.001), and in the 6MWT (P=0.001). In the usual PR program group, significant improvement was observed in the 30-second STST (P=0.042) and in the 6MWT (P=0.001).

CONCLUSION

Our study shows that in stable moderate-to-severe inpatients with COPD, STST is a valid and reliable tool to assess peripheral muscle performance of lower limbs, and is sensitive to a specific PR program.

Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

INTRODUCTION

The aim of this study was to assess the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis.

METHODS

Patients (n = 21) underwent a 16-week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross-sections. Knee extension torque was tested in a dynamometer.

RESULTS

During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training.

CONCLUSIONS

Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth.

Does a land-based compensatory strength-training programme influences the rotator cuff balance of young competitive swimmers?

During the repeated execution of the swimming strokes, the shoulder adductor and internal rotator muscles have a tendency to become proportionally stronger when compared to their antagonist group. This can lead to muscle imbalances. The aim of this study was to examine the effects of a compensatory training programme on the strength and balance of shoulder rotator muscles in young swimmers. A randomized controlled trial design was used. Forty male swimmers took part in the study and were randomly divided into two groups: an experimental group (n = 20) and a training group (n = 20). A control group (n = 16) of young sedentary male students was also evaluated. The experimental group subjects participated in a 16-week shoulder-strength programme with Thera-Band® elastic bands; the training group was restricted to aquatic training. Peak torque of shoulder internal rotator and external rotator (ER) was measured at baseline and after 16 weeks. Concentric action at 1.04 rad s(-1) (3 reps) and 3.14 rad s(-1) (20 reps) was measured using an isokinetic dynamometer. The strength-training programme led to an improvement of the ER strength and shoulder rotator balance in the experimental group (data from both shoulders at 1.04 rad s(-1)). Moreover, concentric action at 3.14 rad s(-1) presented significant differences only for the dominant shoulder. Findings suggest that the prescribed shoulder-strengthening exercises could be a useful training option for young competitive swimmers. They can produce an increase in absolute strength values and greater muscle balance in shoulder rotators.

Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold

This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2 (-1)) and ventilatory equivalent for CO2 (VE·VCO2 (-1)) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2 (-1) stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2 (-1) stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed. Key pointsIt can be identified lactate threshold at half-squat.Exercise intensity is predominantly aerobic.The duration of the half-squat can be maintained over time, ~30 min of discontinuous exercise (21 sets, 15 repetitions, 1 min rest).Lactate threshold intensity may be suitable for older adults, sedentary individuals, patients or subjects with a lower functional capacity and even for resistance sports athletes.

Resistance training improves isokinetic strength and metabolic syndrome-related phenotypes in postmenopausal women

PURPOSE

To examine the effects of resistance training (RT) on metabolic syndrome-related phenotypes in postmenopausal women.

PATIENTS AND METHODS

Twenty-two postmenopausal women (65.0±4.2 years) underwent 12 weeks of whole body progressive training with intensity prescribed based on rating of perceived exertion. Dominant knee extension strength was assessed using an isokinetic dynamometer before and after the intervention. Moreover, all volunteers had blood samples collected for lipid profile, glycemic control, and C-reactive protein analyses. Waist circumference and arterial blood pressure were also measured at baseline and after the training period. Student's t-tests for paired samples and repeated measures ANOVA were used to compare dependent variables, and statistical significance was set at P<0.05.

RESULTS

Isokinetic muscle strength significantly increased (P<0.01) with training. It was observed that waist circumference as well as total and low-density lipoprotein cholesterol levels significantly decreased with training (P<0.01). Total cholesterol/high-density lipoprotein cholesterol ratio, an important marker of cardiovascular disease incidence, was also significantly reduced (from 3.91±0.91 to 3.60±0.74; P<0.01) after the program. Blood glucose, basal insulin, and homeostatic model assessment of insulin resistance were also significantly reduced (P<0.01). No significant alterations were observed for resting blood pressure, triglycerides, or C-reactive protein.

CONCLUSION

Based on the observed results, it can be concluded that a 12-week progressive RT program, besides increasing isokinetic muscle strength, induces beneficial alterations on metabolic syndrome-related phenotypes in postmenopausal women. These findings highlight this mode of exercise as an important component of public health promotion programs for aged women. RT improves isokinetic strength and metabolic syndrome-related phenotypes in postmenopausal women.

The Acute Effect of Concurrent Training on Running Performance Over 6 Days

PURPOSE

This study examined the effects of strength training on alternating days and endurance training on consecutive days on running performance for 6 days.

METHODS

Sixteen male and 8 female moderately trained individuals were evenly assigned into concurrent-training (CCT) and strength-training (ST) groups. The CCT group undertook strength training on alternating days combined with endurance training on consecutive days for 6 days. One week later, the CCT group conducted 3 consecutive days of endurance training only to determine whether fatigue would be induced with endurance training alone (CCT-Con). Endurance training was undertaken to induce endurance-training stimulus and to measure the cost of running (CR), rating of perceived exertion (RPE), and time to exhaustion (TTE). The ST group undertook 3 strength-training sessions on alternating days. Maximal voluntary contraction (MVC), rating of muscle soreness (RMS), and rating of muscle fatigue (RMF) were collected prior to each strength and endurance session.

RESULTS

For the CCT group, small differences were primarily found in CR and RPE (ES = 0.17-0.41). However, moderate-to-large reductions were found for TTE and MVC (ES = 0.65-2.00), whereas large increases in RMS and RMF (ES = 1.23-2.49) were found prior to each strength- and endurance-training session. Small differences were found in MVC for the ST group (ES = 0.11) and during CCT-Con for the CCT group (ES = 0.15-0.31).

CONCLUSION

Combining strength training on alternating days with endurance training on consecutive days impairs MVC and running performance at maximal effort and increases RMS and RMF over 6 days.

Effectiveness of Advanced Stay Strong, Stay Healthy in Community Settings

The goal of this research was to investigate the effectiveness of the 10-week, University of Missouri (MU) Extension strength training program Advanced Stay Strong, Stay Healthy (ASSSH). It was hypothesized that the program can improve strength, balance, agility, and flexibility-all physical measures of falling among seniors. Matched pair t tests were used to compare differences in five physical measures of health, body composition, and percent body fat (%BF). Two-way ANOVA was conducted to examine the age effects on changes in physical health from the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance, and significantly reduced %BF (p < .05). Our data indicate that ASSSH can improve the physical health of senior citizens and can successfully be translated into community practice by MU Extension professionals.

Multimodal high-intensity interval training increases muscle function and metabolic performance in females

High-intensity interval training (HIIT) is a time-efficient method of improving aerobic and anaerobic power and capacity. In most individuals, however, HIIT using modalities such as cycling, running, and rowing does not typically result in increased muscle strength, power, or endurance. The purpose of this study is to compare the physiological outcomes of traditional HIIT using rowing (Row-HIIT) with a novel multimodal HIIT (MM-HIIT) circuit incorporating multiple modalities, including strength exercises, within an interval. Twenty-eight recreationally active women (age 24.7 ± 5.4 years) completed 6 weeks of either Row-HIIT or MM-HIIT and were tested on multiple fitness parameters. MM-HIIT and Row-HIIT resulted in similar improvements (p < 0.05 for post hoc pre- vs. post-training increases for each group) in maximal aerobic power (7% vs. 5%), anaerobic threshold (13% vs. 12%), respiratory compensation threshold (7% vs. 5%), anaerobic power (15% vs. 12%), and anaerobic capacity (18% vs. 14%). The MM-HIIT group had significant (p < 0.01 for all) increases in squat (39%), press (27%), and deadlift (18%) strength, broad jump distance (6%), and squat endurance (280%), whereas the Row-HIIT group had no increase in any muscle performance variable (p values 0.33-0.90). Post-training, 1-repetition maximum (1RM) squat (64.2 ± 13.6 vs. 45.8 ± 16.2 kg, p = 0.02), 1RM press (33.2 ± 3.8 vs. 26.0 ± 9.6 kg, p = 0.01), and squat endurance (23.9 ± 12.3 vs. 10.2 ± 5.6 reps, p < 0.01) were greater in the MM-HIIT group than in the Row-HIIT group. MM-HIIT resulted in similar aerobic and anaerobic adaptations but greater muscle performance increases than Row-HIIT in recreationally active women.

Supplementation with a proprietary blend of ancient peat and apple extract may improve body composition without affecting hematology in resistance-trained men

Adenosine-5'-triphosphate (ATP) is primarily known as a cellular source of energy. Increased ATP levels may have the potential to enhance body composition. A novel, proprietary blend of ancient peat and apple extracts has been reported to increase ATP levels, potentially by enhancing mitochondrial ATP production. Therefore, the purpose of this investigation was to determine the supplement's effects on body composition when consumed during 12 weeks of resistance training. Twenty-five healthy, resistance-trained, male subjects (age, 27.7 ± 4.8 years; height, 176.0 ± 6.5 cm; body mass, 83.2 ± 12.1 kg) completed this study. Subjects supplemented once daily with either 1 serving (150 mg) of a proprietary blend of ancient peat and apple extracts (TRT) or placebo (PLA). Supervised resistance training consisted of 8 weeks of daily undulating periodized training followed by a 2-week overreach and a 2-week taper phase. Body composition was assessed using dual-energy X-ray absorptiometry and ultrasound at weeks 0, 4, 8, 10, and 12. Vital signs and blood markers were assessed at weeks 0, 8, and 12. Significant group × time (p < 0.05) interactions were present for ultrasound-determined cross-sectional area, which increased in TRT (+0.91 cm(2)) versus PLA (-0.08 cm(2)), as well as muscle thickness (TRT: +0.46; PLA: +0.04 cm). A significant group × time (p < 0.05) interaction existed for creatinine (TRT: +0.06; PLA: +0.15 mg/dL), triglycerides (TRT: +24.1; PLA: -20.2 mg/dL), and very-low-density lipoprotein (TRT: +4.9; PLA: -3.9 mg/dL), which remained within clinical ranges. Supplementation with a proprietary blend of ancient peat and apple extracts may enhance resistance training-induced skeletal muscle hypertrophy without affecting fat mass or blood chemistry in healthy males.

Innovative strength training-induced neuroplasticity and increased muscle size and strength in children with spastic cerebral palsy: an experimenter-blind case study--three-month follow-up

BACKGROUND

In children with cerebral palsy (CP), the never-learned-to-use (NLTU) effect and underutilization suppress the normal development of cortical plasticity in the paretic limb, which further inhibits its functional use and increases associated muscle weakness.

OBJECTIVE

To highlight the effects of a novel comprehensive hand repetitive intensive strengthening training system on neuroplastic changes associated with upper extremity (UE) muscle strength and motor performance in children with spastic hemiplegic CP.

METHOD

Two children with spastic hemiplegic CP were recruited. Intervention with the comprehensive hand repetitive intensive strengthening training system was provided for 60 min a day, three times a week, for 10 weeks. Neuroplastic changes, muscle size, strength, and associated motor function were measured using functional magnetic resonance imaging (MRI), ultrasound imaging, and standardized motor tests, respectively.

RESULTS

The functional MRI data showed that the comprehensive hand repetitive intensive strengthening training intervention produced measurable neuroplastic changes in the neural substrates associated with motor control and learning. These neuroplastic changes were associated with increased muscle size, strength and motor function.

CONCLUSIONS

These results provide compelling evidence of neuroplastic changes and associated improvements in muscle size and motor function following innovative upper extremity strengthening exercise.

Physical exercise at the workplace reduces perceived physical exertion during healthcare work: cluster randomized controlled trial

BACKGROUND

High physical exertion during work is a risk factor for musculoskeletal pain and long-term sickness absence. Physical exertion (RPE) reflects the balance between physical work demands and physical capacity of the individual. Thus, increasing the physical capacity through physical exercise may decrease physical exertion during work. This study investigates the effect of workplace-based versus home-based physical exercise on physical exertion during work (WRPE) among healthcare workers.

METHODS

200 female healthcare workers (age: 42.0, body mass index: 24.1, average pain intensity: 3.1 on a scale of 0 to 10, average WRPE: 3.6 on a scale of 0 to 10) from 18 departments at three participating hospitals. Participants were randomly allocated at the cluster level to 10 weeks of: (1) workplace physical exercise (WORK) performed in groups during working hours for 5×10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (2) home-based physical exercise (HOME) performed during leisure time for 5×10 minutes per week. Physical exertion was assessed at baseline and at 10-week follow-up.

RESULTS

2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. Physical exertion was reduced more in WORK than HOME (p<0.01). Between-group differences in physical exertion at follow-up (WORK vs. HOME) was -0.5 points (95% CI -0.8 to -0.2). Within-group effect size (Cohen's d) in WORK and HOME was 0.43 and 0.13, respectively.

CONCLUSIONS

Physical exercise performed at the workplace appears more effective than home-based exercise in reducing physical exertion during daily work tasks in healthcare workers.

Endothelial nitric oxide synthase Glu298Asp gene polymorphism influences body composition and biochemical parameters but not the nitric oxide response to eccentric resistance exercise in elderly obese women

Both endothelial nitric oxide synthase (eNOS) gene polymorphism and nitric oxide (NO) are involved in important cardiovascular, muscular and inflammatory physiological mechanisms during ageing and response to exercise. The aim of this study was to investigate the NO kinetic response following an acute eccentric resistance exercise (ERE) session and the possible effect of the Glu298Asp eNOS gene polymorphism in elderly obese women. Eighty-seven women (age 69·4 ± 6·1 years, body weight 74·9 ± 12·7 kg, height 151·9 ± 6·0 cm and BMI 32·5 ± 5·7 kg m^-2 ) completed seven sets of ten eccentric repetitions at 110% of the ten repetitions maximum (10RM). NO concentrations remained elevated up to 48 h following the acute ERE session as compared with baseline, for GG and GT/TT groups (P<0·05), with no differences between genotypes. The GG genotype group had higher body weight, prevalence of obesity (BMI classification - 81% versus 56%), BMI and higher relative muscle strength, while they had significantly lower triglycerides, VLDL and urea concentrations as compared with TT/TG group. In conclusion, NO remains elevated for up to 48 h after an acute ERE session, without genotype interaction. The TT/TG genotype had a negative impact on triglycerides, VLDL and urea concentrations. Thus, T carriers should increase their attention to cardiovascular risk factor and metabolic disorders.

Neuromuscular and blood lactate responses to squat power training with different rest intervals between sets

Studies investigating the effect of rest interval length (RI) between sets on neuromuscular performance and metabolic response during power training are scarce. Therefore, the purpose of this study was to compare maximal power output, muscular activity and blood lactate concentration following 1, 2 or 3 minutes RI between sets during a squat power training protocol. Twelve resistance-trained men (22.7 ± 3.2 years; 1.79 ± 0.08 cm; 81.8 ± 11.3 kg) performed 6 sets of 6 repetitions of squat exercise at 60% of their 1 repetition maximum. Peak and average power were obtained for each repetition and set using a linear position transducer. Muscular activity and blood lactate were measured pre and post-exercise session. There was no significant difference between RI on peak power and average power. However, peak power decreased 5.6%, 1.9%, and 5.9% after 6 sets using 1, 2 and 3 minutes of RI, respectively. Average power also decreased 10.5% (1 min), 2.6% (2 min), and 4.3% (3 min) after 6 sets. Blood lactate increased similarly during the three training sessions (1-min: 5.5 mMol, 2-min: 4.3 mMol, and 3-min: 4.0 mMol) and no significant changes were observed in the muscle activity after multiple sets, independent of RI length (pooled ES for 1-min: 0.47, 2-min: 0.65, and 3-min: 1.39). From a practical point of view, the results suggest that 1 to 2 minute of RI between sets during squat exercise may be sufficient to recover power output in a designed power training protocol. However, if training duration is malleable, we recommend 2 min of RI for optimal recovery and power output maintenance during the subsequent exercise sets. Key pointsThis study demonstrates that 1 minute of RI between sets is sufficient to maintain maximal power output during multiple sets of a power-based exercise when it is composed of few repetitions and the sets are not performed until failure. Therefore, a short RI should be considered when designing training programs for the development of muscular power.Short RI may be more practical for strength coaches under time constraints (i.e. 1 minute of RI required only 7 minutes to complete an exercise session, while with 2 minutes take 12 minutes, and 17 minutes with 3 minutes of RI).Future research is needed to examine the longitudinal effects of interval rest in training programs designed for the development of muscular power.

Strength fitness and body weight status on markers of cardiometabolic health

INTRODUCTION

Recent evidence suggests that resistance training (RT) may reduce metabolic and cardiovascular disease risk. We investigated whether overweight/class I obese individuals by BMI classification with high strength fitness exhibit cardiovascular/metabolic phenotypes similar to those overweight/obese and untrained or those normal-weight with high strength fitness.

METHODS

A total of 90 young males were categorized into three groups: overweight untrained (OU, n = 30, BMI > 27 kg·m⁻²), overweight trained (OT, n = 30, BMI > 27 kg·m⁻², RT ≥ 4 d·wk⁻¹), and normal-weight trained (NT, n = 30, BMI < 25 kg·m⁻², RT ≥ 4 d·wk⁻¹). Participants were assessed for strength, body composition, central/peripheral blood pressures, arterial stiffness, and markers of cardiovascular and metabolic health.

RESULTS

Body weight was similar in OT and OU and greater than NT (P < 0.00001), and fat mass was different in all groups (P < 0.001). Compared to OU, NT and OT groups exhibited higher relative strength (NT = 46.7%, OT = 44.4%, P < 0.00001), subendocardial viability ratio (NT = 21.0%, P < 0.001; OT = 17.0%, P < 0.01), and lower brachial/central blood pressures (NT P < 0.001; OT P ≤ 0.05); augmentation index and pulse-wave velocity were lower only in OT (P < 0.05). Total cholesterol, low-density lipoprotein (NT P < 0.01, OT P < 0.05), triglycerides (NT = -50.4%, OT = -41.8%, P < 0.001), oxidized LDL (NT = -39.8%, OT = -31.8%, P < 0.001), and CRP (NT = -63.7%, OT = -67.4%, P < 0.01) levels were lower and high-density lipoprotein (NT = 26.9%, OT = 21.4%, P < 0.001) levels were higher in NT and OT compared to OU. NT and OT also exhibited lower amylin (NT = -55.8%, OT = -40.8%) and leptin (NT = -84.6%, OT = -59.4%) and higher adiponectin (NT = 87.5%, P < 0.001; OT = 78.1%, P < 0.01) and sex hormone-binding globulin (NT = 124.4%, OT = 92.3%, P < 0.001). Despite greater total and trunk fat in OT compared with NT, other than glucose and insulin, which were lower in NT than in both OT and OU (OT P < 0.01, OU P < 0.001), OT did not exhibit any impaired biomarker/phenotype compared to NT.

CONCLUSIONS

These findings provide evidence that overweight/class I obese individuals with high strength fitness exhibit metabolic/cardiovascular risk profiles similar to normal-weight, fit individuals rather than overweight/class I obese unfit individuals. Strength training may be important to metabolic and cardiovascular health.

Efficacy of a simple and inexpensive exercise training program for advanced chronic obstructive pulmonary disease patients in community hospitals

BACKGROUND

Exercise training is an important part of pulmonary rehabilitation; however it may not be appropriate for large-scale practice in community hospitals due to the complexity of the program and expensive training equipment, including cycle ergometry and treadmills. This study therefore aims to evaluate the efficacy of a more simplified exercise training program with inexpensive training equipment.

METHODS

A multicentre study of a mild to moderate intensity exercise training program was conducted based on incremental strength and endurance with two 35-40-minute sessions per week for 8 weeks. The program was performed by 30 outpatients from five community hospitals. Patients were monitored regularly for various parameters including strength of trained muscles, level of dyspnea, 6-minute walk distance, and quality of life (QoL) at baseline at 1, 2, 3, 6, 9 and 12 months. Unpaired t-tests were applied to determine the progress of trained muscle strength and minimal clinically important differences (MCIDs) were used to assess clinical outcomes.

RESULTS

Thirty patients (13 males, 17 females) were enrolled with a mean age of 69.1±8.9 years, body mass index 20.5±4.4 kg/m(2), and mean % of predicted forced expiratory volume in the first second (FEV1) 45.1±10.8. According to GOLD classification, eight (26.7%) cases were in stage II, 20 (66.7%) cases in stage III, and two (6.6%) cases in stage IV. Limb and chest wall muscle strength, dyspnea level, exercise capacity and QoL showed statistically significant improvements throughout the 12-month follow-up (P<0.01). There were clinically significant improvements in QoL throughout the 12-month follow-up, exercise capacity from months 2 to 12, and dyspnea levels at months 2, 3 and 9.

CONCLUSIONS

The implementation of a simplified and inexpensive exercise training program was shown to be effective for advanced chronic obstructive pulmonary disease patients in community hospitals.

Dietary intake habits and controlled training on body composition and strength in elite female volleyball players during the season

The purpose of this study was to assess dietary intake of elite female volleyball players (EFVPs, n = 22) during the first 11 weeks of the competitive season. Further, we compared findings for total energy intake and specific macronutrient distribution with the established recommendations for high-intensity athletes. Subjects also engaged in periodized training and we assessed changes in body composition (BC) and strength. Twenty-two EFVPs had dietary intake (7-day dietary recall and food-frequency questionnaire), BC (body mass index (BMI), body fat percentage, fat mass, muscle mass), and 1-repetition maximum (1RM) strength (bench press, military press, back squat, power clean, clean and jerk, pull-over) assessed at baseline (T0, before preseason) and 11 weeks later (T11). Athletes consumed less total kilocalories and carbohydrates (CHO) compared with established recommendations (total kilocalories: 40.7 ± 5.2 kcal/(kg · day)(-1) vs.

RECOMMENDATIONS

50-80 kcal/(kg · day)(-1); CHO: 4.3 ± 0.6 g/(kg · day)(-1) vs.

RECOMMENDATIONS

5-8 g/(kg · day)(-1)). Further, subjects consumed greater protein (2.1 ± 0.4 g/(kg · day)(-1)) compared with recommendations (1.6-1.8 g/(kg · day)(-1)) and greater fat (36.1 ± 4.6% of total kilocalories) than recommendations (20%-35% of total kilocalories). There were improvements (p < 0.05) in BC from T0-T11 (body fat percentage: 17.9% ± 4.2%-16.8% ± 3.6%, -4.7% ± 7.4%; fat mass: 12.7 ± 4.2-11.9 ± 3.8 kg, -4.0% ± 9.2%; muscle mass: 42.8% ± 3.4%-43.3% ± 3.0%, +1.3 ± 3.1%) and 1RM strength (bench press: 39.1 ± 4.5-43.4 ± 4.9 kg; +11.4% ± 9.3%; clean and jerk: 29.7 ± 6.3-34 ± 5.8 kg; +17.7% ± 23.8%); however, there was no change (p > 0.05) in BMI or military press and pull-over. Back squat (p = 0.054; +33.0% ± 83.7%) and power clean (p = 0.056; +26.2% ± 49.0%) increases approached significance. Our findings indicate that EFVPs improved BC and strength despite a dietary intake different from recommendations. This is possibly due to different substrate utilization during exercise in females versus males, thus new recommendations should be considered for high-intensity athletes, which are sex-specific.

Effects of free leucine supplementation and resistance training on muscle strength and functional status in older adults: a randomized controlled trial

OBJECTIVE

To assess the effect of free leucine supplementation combined with resistance training versus resistance training only on muscle strength and functional status in older adults.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel study with two intervention groups. Thirty older adults were randomly assigned to receive either 10 g leucine/day (leucine group [LG], n=15) or a placebo (control group [CG], n=15), plus resistance training over a 12-week period. Maximal overcoming isometric leg strength, functional status, nutritional status, body composition, health-related quality of life, depression, and dietary intake were assessed at 4 and 12 weeks. Missing data at 12 weeks were handled using mixed models for repeated measurements for data imputation.

RESULTS

Twenty-four subjects completed the 4-week assessment and eleven completed the 12-week intervention. Clinically significant gains were found in isometric leg strength at both assessment time points. Analysis of the effect size also showed how participants in LG outperformed those in CG for chair stands and the timed up and go test. No significant changes were observed for the rest of the outcomes.

CONCLUSION

Our combined analysis showed moderate changes in isometric leg muscle strength and certain components of functional status. The magnitude of changes found on these outcomes should be qualified as a positive effect of the concomitant intervention.

Exercise for patients with major depression: a protocol for a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

The lifetime prevalence of major depression is estimated to affect 17% of the population and is considered the second largest health-care problem globally in terms of the number of years lived with disability. The effects of most antidepressant treatments are poor; therefore, exercise has been assessed in a number of randomized clinical trials. A number of reviews have previously analyzed these trials; however, none of these reviews have addresses the effect of exercise for adults diagnosed with major depression.

METHODS/DESIGN

The objective of this systematic review is to investigate the beneficial and harmful effects of exercise, in terms of severity of depression, lack of remission, suicide, and so on, compared with treatment as usual with or without co-interventions in randomized clinical trials involving adults with a clinical diagnosis of major depression. A meta-analysis of the effect estimates of the individual trials, taking bias risk into consideration, will be carried out. Any heterogeneity will be explored using meta-regression and subgroup analyses. Trial sequential analysis will be carried out on the trials to control for risks of random errors. The results from the study will aid health authorities and clinicians to understand whether exercise should be offered to patients with major depression.

Effects of different resistance training frequencies on flexibility in older women

OBJECTIVE

The main purpose of the investigation reported here was to analyze the effect of resistance training (RT) performed at different weekly frequencies on flexibility in older women.

PARTICIPANTS AND METHODS

Fifty-three older women (≥60 years old) were randomly assigned to perform RT either two (n=28; group "G2x"), or three (n=25; group "G3x") times per week. The RT program comprised eight exercises in which the participants performed one set of 10-15 repetitions maximum for a period of 12 weeks. Anthropometric, body-composition, and flexibility measurements were made at baseline and post-study. The flexibility measurements were obtained by a fleximeter.

RESULTS

A significant group-by-time interaction (P<0.01) was observed for frontal hip flexion, in which G3x showed a higher increase than G2x (+12.8% and +3.0%, respectively). Both groups increased flexibility in cervical extension (G2x=+19.1%, G3x=+20.0%), right hip flexion (G2x=+14.6%, G3x=+15.9%), and left hip flexion (G2x=+25.7%, G3x=+19.2%), with no statistical difference between groups. No statistically significant differences were noted for the increase in skeletal muscle mass between training three versus two times a week (+7.4% vs +4.4%, respectively).

CONCLUSION

Twelve weeks of RT improves the flexibility of different joint movements in older women, and the higher frequency induces greater increases for frontal hip flexion.

Change in weight and body composition in obese subjects following a hypocaloric diet plus different training programs or physical activity recommendations

The aim of the present study was to compare the effects of different physical activity programs, in combination with a hypocaloric diet, on anthropometric variables and body composition in obese subjects. Ninety-six obese (men: n = 48; women: n = 48; age range: 18-50 yr) participated in a supervised 22-wk program. They were randomized into four groups: strength training (S; n = 24), endurance training (E; n = 26), combined strength + endurance training (SE; n = 24), and physical activity recommendations (C; n = 22). In addition, all groups followed the same hypocaloric diet. At baseline and at the end of the intervention, dietetic and physical activity variables were assessed using validated questionnaires. Anthropometric variables were recorded along with body composition variables measured using dual-energy X-ray absorptiometry techniques. At the end of the intervention, significant improvements were seen within groups in terms of body weight (S: -9.21 ± 0.83 kg; E: -10.55 ± 0.80 kg; SE: -9.88 ± 0.85 kg; C: -8.69 ± 0.89 kg), and total fat mass (S: -5.24 ± 0.55%; E: -5.35 ± 0.55%; SE: -4.85 ± 0.56%; C: -4.89 ± 0.59%). No differences were seen between groups at this time in terms of any other anthropometric or body composition variables examined. All groups increased their total physical activity in metabolic equivalents (MET) per week during the intervention, but with no difference between groups (S: 976 ± 367 MET-min/wk; E: 954 ± 355 MET-min/wk; SE: 1 329 ± 345 MET-min/wk; C: 763 ± 410 MET-min/wk). This study shows that, when combined with a hypocaloric diet, exercise training and adherence to physical activity recommendations are equally effective at reducing body weight and modifying body composition in the treatment of obesity (Clinical Trials Gov. number: NCT01116856).

Strength and aerobic training in overweight females in Gdansk, Poland

We compared the effects of 16-week-training on rest metabolic rate, aerobic power, and body fat, and the post-exercise effects upon rest oxygen uptake and respiratory exchange ratio in overweight middle-aged females. Twenty nine overweight women (BMI 29.9 ± 1.2 kg*m^-2) participated in training (3 days a week). The subjects were divided onto groups of aerobic (AT) and strength (ST) training. The results showed that the total body mass decrease and VO₂ max increase did not differ in both groups. Decrease in waist circumference after 16 weeks was higher in the ST group. In the ST group fat-free mass increased during the first 8 weeks. Rest metabolic rate was increased significantly at 16th week compared to initial value in ST group only. Significant increase in post-exercise resting VO₂ and respiratory exchange ratio at 12 and 36 h was observed after the strength training session only. Increase in rest metabolic rate and post-exercise rest energy expenditure occurred after strength training but not after aerobic training despite the similar increase in aerobic power. The effect of 8-16 weeks of strength training on body mass decrease was higher in comparison to aerobic training.

Mirror illusion reduces motor cortical inhibition in the ipsilateral primary motor cortex during forceful unilateral muscle contractions

Forceful, unilateral contractions modulate corticomotor paths targeting the resting, contralateral hand. However, it is unknown whether mirror-viewing of a slowly moving but forcefully contracting hand would additionally affect these paths. Here we examined corticospinal excitability and short-interval intracortical inhibition (SICI) of the right-ipsilateral primary motor cortex (M1) in healthy young adults under no-mirror and mirror conditions at rest and during right wrist flexion at 60% maximal voluntary contraction (MVC). During the no-mirror conditions neither hand was visible, whereas in the mirror conditions participants looked at the right hand's reflection in the mirror. Corticospinal excitability increased during contractions in the left flexor carpi radialis (FCR) (contraction 0.41 mV vs. rest 0.21 mV) and extensor carpi radialis (ECR) (contraction 0.56 mV vs. rest 0.39 mV), but there was no mirror effect (FCR: P = 0.743, ηp (2) = 0.005; ECR: P = 0.712, ηp (2) = 0.005). However, mirror-viewing of the contracting and moving wrist attenuated SICI relative to test pulse in the left FCR by ∼9% compared with the other conditions (P < 0.05, d ≥ 0.62). Electromyographic activity in the resting left hand prior to stimulation was not affected by the mirror (FCR: P = 0.255, ηp (2) = 0.049; ECR: P = 0.343, ηp (2) = 0.035) but increased twofold during contractions. Thus viewing the moving hand in the mirror and not just the mirror image of the nonmoving hand seems to affect motor cortical inhibitory networks in the M1 associated with the mirror image. Future studies should determine whether the use of a mirror could increase interlimb transfer produced by cross-education, especially in patient groups with unilateral orthopedic and neurological conditions.

Effect of resistance training using bodyweight in the elderly: Comparison of resistance exercise movement between slow and normal speed movement

AIM

The present study investigated whether a slow movement protocol can be applied to resistance training using bodyweight. In addition, the intervention program combined plyometric exercise with resistance exercise to improve physical function overall.

METHODS

A total of 39 active elderly adults participated in a 16-week intervention. The program consisted of five resistance exercises and four plyometric exercises using their own bodyweight with a single set for each exercise. Participants were assigned to one of two experimental groups. One group carried out resistance exercise with slow movement and tonic force generation (3-s concentric, 3-s eccentric and 1-s isometric actions with no rest between each repetition). The other group as a movement comparison followed the same regimen, but at normal speed (1-s eccentric and 1-s concentric actions with 1-s rest between each repetition). Muscle size, strength and physical function were measured before and after the intervention period.

RESULTS

After the intervention, strengths of upper and lower limbs, and maximum leg extensor power were significantly improved in both groups. Muscle size did not change in either group. There were no significant differences in any of the parameters between groups.

CONCLUSIONS

The intervention program using only own bodyweight that comprised resistance exercise with slow movement and plyometric exercise can improve physical function in the elderly, even with single sets for each exercise. However, there was no enhanced muscle hypertrophic effect. Further attempts, such as increasing performing multiple sets, would be required to induce muscle hypertrophy. Geriatr Gerontol Int 2015; 15: 1270-1277.

Long-term efficacy of intensive cycle ergometer exercise training program for advanced COPD patients

Background

Exercise training has been incorporated into the international guidelines for the treatment of chronic obstructive pulmonary disease (COPD). However, the long-term efficacy of the training program for patients with advanced COPD has never been evaluated in Thailand.

Purpose

To determine the long-term efficacy of intensive cycle ergometer exercise program on various clinical parameters of patients with advanced COPD.

Materials and methods

The patients with advanced COPD were separated into two groups: the intensive ergometer exercise program group and the control group. The clinical parameters of all the patients were assessed at baseline, every month for the first 3 months, and then every 3 months until they had completed the 24-month follow-up. Mann–Whitney U test was used to compare baseline mean differences between the groups. Repeated measure analysis was applied to determine the progress in all parameters during the entire follow-up period. Mean incase imputation method was applied to estimate the parameters of dropout cases.

Results

A total of 41 patients were enrolled: 27 in the intensive ergometer exercise program group and 14 in the control group. The intensive cycle ergometer exercise program group showed statistically significant improvements in muscle strength (from month 1 till the end of the study, month 24), endurance time (from month 1 till the end of measurement, month 12) and clinically significant improvements in 6-minute walk distance (from month 2 until month 9), dyspnea severity by transitional dyspnea index (from month 1 till the end of the study, month 24), and quality of life (from month 1 till the end of the study, month 24). There was no significant difference in survival rates between the groups.

Conclusion

The intensive ergometer exercise training program revealed meaningful long-term improvements in various clinical parameters for up to 2 years. These promising results should encourage health care professionals to promote exercise training for patients with advanced COPD who have limited daily activities despite optimal medication control.

Influence of exercise order on electromyographic activity during upper body resistance training

The purpose of this study was to investigate the effects of exercise order on electromyographic activity in different muscle groups among youth men with experience in strength training. Three sets of 8 RM were performed of each exercise in two sequences order: (a) sequence A: bench press, chest fly, shoulder press, shoulder abduction, close grip bench press and lying triceps extension; (b) sequence B: the opposite order. The electromyographic activity was analyzed in the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii, normalized for maximal voluntary isometric contraction. The muscles activity of the sternocostal head of the pectoralis major, anterior deltoid, and long head triceps brachii showed significant interaction between sequence and exercise. The sternocostal head of the pectoralis major showed considerably higher activity in sequence A (100.13 ± 13.56%) than sequence B (81.47 ± 13.09%) for the chest fly. The anterior deltoid showed significantly higher electromyographic activity in sequence B (86.81 ± 40.43%) than sequence A (66.15 ± 22.02%) for the chest fly, whereas for the lying triceps extension, the electromyographic activity was significantly higher in sequence A (53.89 ± 27.09%) than sequence B (34.32 ± 23.70%). For the long head triceps brachii, only the shoulder press showed differences between sequences (A = 52.43 ± 14.64 vs. B = 38.53 ± 16.26). The present study showed that the exercise order could modify the training results even though there was no alteration in volume and intensity of the exercise. These changes may result in different training adaptations.

Acute blood pressure changes are related to chronic effects of resistance exercise in medicated hypertensives elderly women

BACKGROUND

A previous study observed that the chronic effects of aerobic training on blood pressure (BP) are related to acute BP responses after a single bout of aerobic exercise. However, whether similar responses are observed with resistance exercise (RE) remains obscure. Thus, this study analysed the relationship between the acute BP responses to a single bout of RE and chronic changes in resting BP after a RE training in medicated hypertensive elderly women.

METHODS AND RESULTS

Twenty medicated hypertensive women participated in the study. They underwent an acute RE bout where BP and heart rate (HR) were obtained at rest and for 60 min after the RE. Subsequently, the participants underwent a progressive RE training for 12 weeks at 60-80% of maximal strength test. Resting BP and HR were also obtained after the RE training. The chronic decreases in systolic and diastolic BP were significantly greater in the participants who experienced acutely decreased systolic and diastolic BP, respectively (P<0·05). The changes in systolic BP after acute RE were correlated with the chronic changes in resting systolic BP after RE training (r = 0·47; P = 0·03). Similar correlations between acute and chronic responses were also observed for diastolic BP (r = 0·70; P = 0·01), mean BP (r = 0·58; P = 0·01), HR (r = 0·73; P<0·01) and RPP (r = 0·52; P = 0·01).

CONCLUSION

Similar to previously work involving aerobic exercise, BP responses to a single bout of RE are strongly related to chronic effects of RE training on BP in medicated hypertensive elderly women.

Acute endocrine responses to different strength exercise order in men

This study compared the effects of order of muscle groups' exercised (larger to smaller muscles vs. smaller to larger muscles) on the acute levels of total testosterone, free testosterone and cortisol during resistance training (RT) sessions. Healthy male participants (n=8; age: 28.8 ± 6.4 years; body mass: 87.0 ± 10.6 kg; body height: 181.0 ± 0.7 cm; BMI: 26.5 ± 4.1) were randomly separated into two experimental groups. The first group (LG-SM) performed an RT session (3 sets of 10 repetitions and a 2 min rest period) of the exercises in following order: bench press (BP), lat pulldown (LP), barbell shoulder press (BSP), triceps pushdown (TP) and barbell cut (BC). The second group (SM-LG) performed an RT session in following order: BC, TP, BSP, LA, BP. Blood was collected at the end of the last repetition of each session. Control samples of blood were taken after 30 min of rest. Significant differences were observed in the concentrations of total testosterone (p < 0.05), free testosterone (p < 0.0001) and cortisol (p < 0.0001) after both RT sessions in comparison to rest. However, when comparing LG-SM and SM-LG, no significant differences were found. The results suggest that, while RT sessions induce an acute change in the levels of testosterone and cortisol, this response is independent of the order of exercising muscle groups.

Oxygen uptake and heart rate kinetics after different types of resistance exercise

Oxygen uptake (VO2) and heart rate (HR) kinetics after exercise are important indicators of fitness and cardiovascular health. However, these variables have been little investigated in resistance exercise (RE). The current study compared post-exercise kinetics of VO2 and the HR among different types of REs. The study included 14 males (age: 26.5±5.4 years, body mass: 80.1±11.4 kg, body height: 1.77±0.07 m, fat content: 11.3±4.6%) with RE experience. Dynamic muscle strength was measured using one repetition maximum (1RM) with regard to the half-squat, bench press, pull-down, and triceps pushdown exercises. The participants performed a maximum number of repetitions at 80% of 1RM for each exercise, separated by a recovery period of 60 minutes. VO2 was measured using ergospirometry. VO2 and HR kinetics were assessed using the time constant of the recovery curves, and excess oxygen consumption (EPOC) was calculated afterward. Significant differences were not observed across the exercises with regard to VO2 kinetics. However, the half-squat exercise elicited a greater EPOC than the bench press and triceps pushdown exercises (p<.05). HR kinetics was slower for the half-squat exercise than for the other exercises (p<.05). These findings confirm that the type of RE influences both the cardiac autonomic response post-exercise and EPOC, but not VO2 kinetics.

The development of swimming power

PURPOSE

the aim of this study was to investigate the effects of the transfer strength training method on swimming power.

METHODS

twenty male swimmers "master" were randomly allocated to strength (n= 10, ST) and swimming training (n=10, SW) groups. Both groups performed six-weeks training based on swimming training for SW and strength training which consisted in a weight training session immediately followed by the maximum swimming velocity. The performance in both groups was assessed by Maximal-Mechanical-External-Power (MMEP) before and after the six-weeks period, using a custom ergometer that provided force, velocity, and power measurement in water.

RESULTS

a significant increased MMEP in ST group (5.73% with p< 0.05) was obtained by an increased strength (11.70% with p< 0.05) and a decreased velocity (4.99% with p> 0.05). Conversely, in the SW group there was a decreased in MMEP (7.31%; p< 0.05), force and velocity (4.16%, and 3.45; respectively p> 0.05).

CONCLUSION

this study showed that the transfer training method, based on combination of weight training (in dry condition) immediately followed by fast swim (in water) significantly improves swimming-power in master.

Hydro aerobics on functional and cardiorespiratory ability in postmenopausal women

The current study aimed to compare the effects of two exercise programs (Strength Training and Hydro Gymnastics) on the functional and cardiorespiratory abilities of Portuguese postmenopausal women. The study population consisted of 38 volunteers (age: 66.9 ± 6.1 years, body mass: 73.70 ± 10.38 kg, and body height: 1.55 ± 0.10 m). Subjects were randomly divided into two experimental groups and one control group: one group performed 24 weeks of strength training (GST; n = 14), another performed 24 weeks of hydro gymnastics (GH; n = 17) and a control group (CG; n = 7), where the subjects continued with their regular daily activities without involvement in any physical exercise program. Three assessments were performed: before the beginning of the program, 12 weeks after the start of the training program and 24 weeks after the start of the program. To assess the functional ability of the participants, several tests proposed by Jones and Rikli (2002) were performed. To evaluate the cardiorespiratory ability of the participants, a modified treadmill Bruce test was applied. Significant differences (p<0.05) were found between the two training methods in the tests, which primarily demanded muscular strength. Body mass and the body mass index showed significant differences during the three stages of assessment in the GST group (p<0.05). With respect to the values that represent the variables of cardiorespiratory ability, positive and significant changes were observed in the two experimental groups. It was concluded that both exercise programs promoted improvements in some indicators of the functional and cardiorespiratory abilities of Portuguese postmenopausal women.

The effects of different exercise programmes on female body composition

The purpose of this study was to verify the effects of 16 weeks of practicing different exercise programmes on body composition. This is an exploratory and descriptive study of 89 women aged 25 to 55 years (41.42 ± 9.23 years). The subjects were randomly divided into three experimental groups (EG): practitioners of strength training (SG), dance (DG), hydrogymnastics (HG), and a control group (CG) with sedentary women. Measurements of body mass and height, circumferences of the chest, waist, abdomen, hips, thighs, calves, and skinfolds of the triceps, suprailiac and thigh were registered in three different moments: prior to the commencement of the training program, again after 8 weeks of training, and finally after 16 weeks of training. Body density was estimated by using the trifold protocol by Jackson, Pollock and Ward. The ANOVA and deltas of change (Δ%) were used for data analysis. The level of significance was set at p<0.05. The effects of greater statistical significance on body composition related the variables “time”, “group” and the interaction between the two (time × group) were observed for the percentage of fat - F% (F (1.79, 152.52) = 24.59, p <0.001, η ² = 0.22), fat mass - FM (F (1.75, 149.01) = 12.65, p <0.001, η ² = 0.13) and lean mass - LM (F (1.77, 150.66) = 47.38, p <0.001, η ² = 0.36). The HG and SG were more beneficial in reducing F%. It was observed that the EG indicated healthier anthropometric aspects compared to the CG, regardless of the type of exercise programmes practiced. The time factor was more representative over the effects of exercise on anthropometric dimensions.

The acute effect of resistance exercise with blood flow restriction with hemodynamic variables on hypertensive subjects

The purpose of this study was to analyze systolic blood pressure (SBP), diastolic blood pressure (DBP) and the heart rate (HR) before, during and after training at moderate intensity (MI, 50%-1RM) and at low intensity with blood flow restriction (LIBFR). In a randomized controlled trial study, 14 subjects (average age 45±9,9 years) performed one of the exercise protocols during two separate visits to the laboratory. SBP, DBP and HR measurements were collected prior to the start of the set and 15, 30, 45 and 60 minutes after knee extension exercises. Repeated measures of analysis of variance (ANOVA) were used to identify significant variables (2 × 5; group × time). The results demonstrated a significant reduction in SBP in the LIBFR group. These results provide evidence that strength training performed acutely alters hemodynamic variables. However, training with blood flow restriction is more efficient in reducing blood pressure in hypertensive individuals than training with moderate intensity.

Development and validity of a scale of perception of velocity in resistance exercise

This aims of this study were twofold; 1) to development a new scale of perceived velocity in the bench press exercise and 2) to examine the scales concurrent validity. Twenty one physically active males with mean ±SD age, height and weights of: 27.5 ± 4.7 years, 1.77 ± 0.07 m, and 79.8 ± 10.3 kg respectively, took part in the study. The criterion variable used to test the validity of the new scale was the mean execution velocity (Velreal) of the bench press exercise. Three intensities (light loads [< 40% 1RM], medium loads [40% -70% 1RM] and heavy loads [> 70% 1RM]) were measured randomly during 5 days of testing. Perceived velocity (Velscale) was measured immediately after each exercise set using the new scale. A positive linear correlation (r range = 0.69 to 0.81) was found in all three intensities, analyzed individually, between the Velreal and Velscale. Pearson correlations showed a greater frequency of scale use resulted higher correlation values (range r = 0.88 to 0.96). This study provides evidence of the concurrent validity of a new scale of perceived velocity in the bench press exercise in trained adult males. These results suggest the exercise intensity of the bench press can be quantified quickly and effective using this new scale of perceived velocity, particularly when training for maximum power. Key PointsMeasurement of perception of velocity can complement other scales of perception such as the 15 category Borg scale or the OMNI-RES.The results obtained in this study show that there was a positive correlation between the perceived velocity measured by the scale and actual velocityRegular use of the new scale of perceived velocity in external resistance training provides athletes with continuous feedback of execution velocity in each repetition and set, especially with high power loads.

Comparison of isokinetic hip abduction and adduction peak torques and ratio between sexes

OBJECTIVE

To evaluate hip abductor and adductor peak torque outputs and compare their ratios between sexes.

DESIGN

A cross-sectional laboratory-controlled study.

SETTING

Participants visited a laboratory and performed an isokinetic hip abductor and adductor test. All participants performed 2 sets of 5 repetitions of concentric hip abduction and adduction in a standing position at 60 degrees per second. Gravity was determined as a function of joint angle relative to the horizontal plane and was corrected by normalizing the weight of the limb on an individual basis.

PARTICIPANTS

A total of 36 collegiate athletes.

INDEPENDENT VARIABLES

Sex (20 females and 16 males).

MAIN OUTCOME MEASURES

Bilateral peak hip abductor and adductor torques were measured. The 3 highest peak torque values were averaged for each subject.

RESULTS

Independent t tests were used to compare sex differences in hip abductor and adductor peak torques and the abductor:adductor peak torque ratios. Males demonstrated significantly greater hip abductor peak torque compared with females (males 1.29 ± 0.24 Nm/kg, females 1.13 ± 0.20 Nm/kg; P = 0.03). Neither hip adductor peak torque nor their ratios differed between sexes.

CONCLUSIONS

Sex differences in hip abductor strength were observed. The role of weaker hip abductors in females deserves further attention and may be a factor for higher risk of knee pathologies.

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

The anxiolytic effects of resistance exercise

Numerous studies have revealed the beneficial effects of regular exercise across a variety of mental health measures. Although a great deal of attention has been paid to the role of aerobic exercise, less is known about the role of resistance exercise (i.e., strength training) in mental health outcomes. Resistance exercise includes a broad group of procedures that evoke repeated muscle action against resistances above those encountered in daily life. A growing body of literature has identified anxiolytic effects of resistance exercise in human populations after both single-bout sessions and long-term training. This research has shown that resistance training at a low-to-moderate intensity (<70% 1 repetition maximum) produces the most reliable and robust decreases in anxiety. Importantly, anxiolytic effects have been observed across a diverse range of populations and dependent measures. These findings provide support for the use of resistance exercise in the clinical management of anxiety.

Effects of Strength Training Combined with Specific Plyometric exercises on body composition, vertical jump height and lower limb strength development in elite male handball players: a case study

The purpose of the present study was to identify the effects of a strength training program combined with specific plyometric exercises on body composition, vertical jump (VJ) height and strength development of lower limbs in elite male handball players. A 12-week program with combined strength and specific plyometric exercises was carried out for 7 weeks. Twelve elite male handball players (age: 21.6 ± 1.73) competing in the Portuguese Major League participated in the study. Besides the anthropometric measurements, several standardized jump tests were applied to assess VJ performance together with the strength development of the lower limbs in an isokinetic setting. No significant changes were found in body circumferences and diameters. Body fat content and fat mass decreased by 16.4 and 15.7% respectively, while lean body mass increased by 2.1%. Despite small significance, there was in fact an increase in squat jump (SJ), counter movement jump (CMJ) and 40 consecutive jumps after the training period (6.1, 3.8 and 6.8%, respectively). After the applied protocol, peak torque increased in lower limb extension and flexion in the majority of the movements assessed at 90ºs-1. Consequently, it is possible to conclude that combining general strength-training with plyometric exercises can not only increase lower limb strength and improve VJ performance but also reduce body fat content.

Neuromuscular response differences to power vs strength back squat exercise in elite athletes

The study's aim was to establish the neuromuscular responses in elite athletes during and following maximal 'explosive' regular back squat exercise at heavy, moderate, and light loads. Ten elite track and field athletes completed 10 sets of five maximal squat repetitions on three separate days. Knee extension maximal isometric voluntary contraction (MIVC), rate of force development (RFD) and evoked peak twitch force (Pt) assessments were made pre- and post-session. Surface electromyography [root mean square (RMS)] and mechanical measurements were recorded during repetitions. The heavy session resulted in the greatest repetition impulse in comparison to moderate and light sessions (P < 0.001), while the latter showed highest repetition power (P < 0.001). MIVC, RFD, and Pt were significantly reduced post-session (P < 0.01), with greatest reduction observed after the heavy, followed by the moderate and light sessions accordingly. Power significantly reduced during the heavy session only (P < 0.001), and greater increases in RMS occurred during heavy session (P < 0.001), followed by moderate, with no change during light session. In conclusion, this study has shown in elite athletes that the moderate load is optimal for providing a neuromuscular stimulus but with limited fatigue. This type of intervention could be potentially used in the development of both strength and power in elite athletic populations.

Effects of aerobic training, resistance training, or combined resistance-aerobic training on the left ventricular myocardium in a rat model

This study follows the left ventricular (LV) hypertrophy in rats undergoing aerobic training alone (A), resistance training alone (R), or combined resistance and aerobic training (RA) (usually referred as concurrent training) program. A sedentary control group (C) was included. LV remodeling was evaluated using electron and light microscopy. The LV weight to body weight (LVW: BW) increased 11.4% in A group, 35% in the R group, and 18% in the RA group compared to the C group. The LV thickness increased 6% in the A group, 17% in the R group, and 10% in the RA group. The LV internal diameter increased 19% in the A group, 3% in the R group, and 8% in the RA group compared with the C group. The cross-sectional area of cardiomyocyte increased by 1% with the A group, 27% with R group, and 12% with RA training. The capillary density increased by 5.4% with A training, 11.0% with R training, and 7.7% with RA training compared with the C group. The volume fraction of interstitial collagen increased by 0.4% with training A, increased by 2.8% with R training, and 0.9% with RA training. In conclusion, except for the LV internal diameter, which increased more in the A group, the cardiac parameters increased more in the R group than in the other groups and in RA group than in A group. Collagen density increased from 5.4 ± 0.8% in the C group to 5.8 ± 0.6% in the A group (n. s.) (P > 0.05), to 8.2 ± 0.7% in the R group (P < 0.05), and to 6.3 ± 0.4% in the RA group (P < 0.05). These results demonstrate a significant increase for collagen content in the LV with R and RA exercise, but the increase was higher with R training alone than with RA training.

Effect of exercise on anthropometric measures and serum lipids in older individuals: a systematic review and meta-analysis

OBJECTIVES

Overweight and obesity are increasing in individuals over age 60 years. This systematic review quantifies the effect of exercise on body mass index (BMI), waist circumference (WC) and lipids in overweight and obese individuals over the age of 60 years.

SETTINGS

Nine randomised controlled trials conducted in Brazil, Great Britain, Iceland, Japan and the USA compared aerobic and/or resistance exercise with a control group.

PARTICIPANTS

Final analysis reviewed 1166 participants over the age of 60 years for 3-9 months.

PRIMARY OUTCOME MEASURES

This study reviewed the effects of exercise on BMI, WC and low-density lipoprotein (LDL).

RESULTS

Exercise produced a significant reduction in BMI (-1.01 kg/m(2), 95% CI -2.00 to -0.01) and WC (-3.09 cm, 95% CI -4.14 to -2.04) but not LDL cholesterol (-0.31 mg/dL, 95% CI -0.81 to 0.19). Analyses revealed substantial heterogeneity likely due to the type and intensity of exercise. Data on adverse effects were minimal. The overall level of evidence is moderate due to imprecision and heterogeneity.

CONCLUSIONS

Exercise in overweight and obese older individuals improves anthropometric measures such as BMI and WC. The effect of exercise on serum lipids is unclear.

Ventilatory requirements of quadriceps resistance training in people with COPD and healthy controls

Background

It is proposed that resistance training (RT) does not activate the cardiopulmonary system to the same extent as whole-body exercise. This is important for patients with chronic obstructive pulmonary disease (COPD) who are ventilatory limited.

Objective

The aim was to assess the ventilatory response to an isokinetic quadriceps RT program in people with COPD and healthy controls.

Design

Observational.

Registration number

ISRCTN22764439.

Setting

Outpatient, university teaching hospital.

Participants and outcome measures

People with COPD (n=14) and healthy controls (n=11) underwent breath-by-breath analysis of their ventilation during an RT session (five sets of 30 maximal knee extensions at 180°/sec). Subjects performed a maximal cycle ergometry test (CET) at baseline. Peak ventilation (VE; L/min) and oxygen consumption (VO₂; mL/kg/min) were collected. The same system measured VO₂ and VE during the RT session. Parameters are presented as a percentage of the maximal CET. Isokinetic workload, symptom scores, heart rate (HR), and oxygen saturation were documented post-training.

Results

People with COPD worked at higher percentages of their maximal capacity than controls (mean range between sets 1–5 for VO₂ =49.1%–60.1% [COPD], 45.7%–51.43% [controls] and for VE =57.6%–72.2% [COPD], 49.8%–63.6% [controls]), although this was not statistically significant (P>0.1 in all cases). In absolute terms, the difference between groups was only significant for actual VO₂ on set 2 (P<0.05). Controls performed more isokinetic work than patients with COPD (P<0.05). Median Borg symptom scores after RT were the same in both groups (3 breathlessness, 13 exertion), no de-saturation occurred, and both groups were training at ≥65% of their maximum HR.

Conclusion

No statistically significant differences were found between people with COPD and healthy controls for VO₂ and VE achieved during training. The symptoms associated with training were within acceptable limits.

Correct, fake and absent pre-information does not affect the occurrence and magnitude of the bilateral force deficit

The present study examined whether different pre-information conditions could lead to a volitional modulation of the occurrence and magnitude of the bilateral force deficit (BFD) during isometric leg press. Twenty trained male adults (age: 24.5 ± 1.7 years; weight: 77.5 ± 7.1 kg; height: 1.81 ± 0.05 m) were examined on three days within a week. Isometric leg press was performed on a negatively inclined leg press slide. Each participant completed three maximal isometric strength test sessions with different pre-information conditions given in a graphical chart: no pre-information (NPI; first day), false pre-information (FPI; bilateral force > sum of unilateral forces; second or third day) and correct pre-information (CPI; bilateral force < sum of unilateral forces; second or third day) during bilateral, unilateral-left and unilateral-right leg-press. The sum of left- and right-sided force values were calculated for bilateral (FBL = FBL_left + FBL_right) and unilateral (FUL = FUL_left + FUL_right) analyses. Force data for NPI revealed: Mean (SD): FUL_NPI = 3023 N (435) vs. FBL_NPI = 2812 (453); FPI showed FUL_FPI = 3013 N (459) vs. FBL_FPI = 2843 (446) and the CPI revealed FUL_CPI = 3035 (425) vs. FBL_CPI = 2844 (385). The three (no, false, correct) x 2 (FUL, FBL) rANOVA revealed a high significant main effect of Force (F = 61.82, p < 0.001). No significant main effect of the factor Condition and no significant interaction between Force x Condition was observed. The BFD does not rely on the trueness of the given pre-information (no, false, correct). Cognition-based volitional influences on the BFD on supra-spinal level seem negligible. Key pointsBFD is reliable occurring phenomenonAvailable theoretical knowledge does not affect the BFDAlternating sport should include alternating strength exercises.