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This study explored the effect of different dual-task (DT) training programs on DT interference in adults with intellectual disability. Center-of-pressure (CoP) mean velocity in single-task (ST) and cognitive-DT conditions and the Timed Up-and-Go Test (TUGT) during ST, cognitive-DT, and motor-DT conditions were assessed before and after intervention in a cognitive–motor training group, a motor–motor training group, and a control group. Before training, CoP mean velocity and TUGT time increased (p <.001) in DT compared with the ST condition. After training, the CoP mean velocity values remained unchanged (p =.07) in DT compared with the ST condition among the cognitive–motor training group. Furthermore, compared with the ST condition, no increase (p = 1) was reported in the TUGT time during the cognitive-DT condition for the cognitive–motor training group and during the motor-DT for the motor–motor training group (p =.12). The effect of DT training on DT interference depends on the training modality. [ABSTRACT FROM AUTHOR]

Individuals with intellectual disabilities often face unique challenges in physical capabilities, making traditional training methods less effective for their specific needs. This study aimed to investigate the effect of combining balance, plyometric, and strength (CBPS) training with sprint training on physical performance in male athletes with intellectual disabilities. Twenty-seven participants were randomly assigned to either a CBPS group or a control group that only maintained their regular sprint training. Participants underwent pre- and posttraining tests, including measures of balance, jumping, agility, and sprinting ability. The results showed that the CBPS group demonstrated significant improvements (p <.05) in one-leg stance, crossover-hop jump, squat jump, countermovement jump, and 10- and 30-m sprint at posttraining compared with pretraining. CBPS training combined with sprinting significantly improves physical performance in male athletes with intellectual disabilities, suggesting implications for tailored training programs to enhance their physical fitness and overall health. [ABSTRACT FROM AUTHOR]

This study explored the acute effects of different running intensities on cognitive and motor performances in individuals with intellectual disability (ID). An ID group (age, M = 15.25 years, SD = 2.76) and a control group without ID (age, M = 15.11 years, SD = 1.54) performed visual simple and choice reaction times, auditory simple reaction time, and finger tapping tests before and after running at low or moderate intensity (30% and 60% of heart rate reserve [HRR], respectively). Visual simple reaction time values decreased (p <.001) after both intensities at all time points with higher (p =.007) extend after the 60% HRR intensity for both groups. After both intensities, the VCRT decreased (p <.001) in the ID group at all time points compared with preexercise (Pre-EX) while, in the control group, these values decreased (p <.001) only immediately (IM-EX) and after 10 min (Post-10) of exercise cessation. Compared withs Pre-EX, in the ID group, the auditory simple reaction time values decreased (p <.001) at all time points after the 30% HHR intensity whereas, after the 60% HRR, these values decreased only at IM-EX (p <.001), Post-10 (p =.001) and Post-20 (p <.001). In the control group, auditory simple reaction time values decreased (p =.002) only after the 30% HRR intensity at IM-EX. The finger tapping test increased at IM-EX (p <.001) and at Post-20 (p =.001) compared to Pre-EX in both groups only after the 30% HHR intensity and for the dominant hand. The effect of physical exercise on cognitive performances in individuals with ID seems to depend on the cognitive test type as well as the exercise intensity. [ABSTRACT FROM AUTHOR]

In the current study we aimed to investigate the effect of specific dual task training (SDTT) compared to conventional soccer training (CST) on motor and cognitive performances in U13 elite soccer players. Twenty-four young soccer players (all males) participated in this study. We measured their change of direction ability (CODA) and cognitive performances (cognitive flexibility and inhibition) before and after four weeks in either the SDTT group or the CST group. We administered the Trail-Making Test (TMT) to evaluate cognitive flexibility and the Stroop test to evaluate cognitive inhibition. We assessed CODA using the t test (TT). After training, CODA (p <.001), cognitive flexibility (p <.001), and inhibition (p <.001) were improved only in the SDTT group. These results suggest that SDTT seems more suitable than CST to optimally improve both CODA and cognitive performances in U13 elite soccer players. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of 12-week Zumba dancing on postural control and cognitive parameters and the correlations between these parameters in middle-aged women. Thirty-eight women, aged between 50 and 60 years, were randomly allocated to a Zumba group (ZG) or control group. Postural control and cognitive functions [working memory (WM) and reaction time (RT)] were assessed before and after 12 weeks of a Zumba dancing program using a stabilometric force platform, Corsi Block-Tapping Task and Simple RT tests, respectively. The results indicate that ZG showed significantly (p<.01) better balance performances when standing on a stable surface in both visual conditions [firm surface with eyes opened (EO) (20,9%) and eyes closed (EC) (12.3%)]. However, when standing on an unstable surface in both visual conditions (foam surface with EO/EC), the ZG showed no significant improvement in postural control. It seems that the benefits of Zumba on postural control depend on the sensory condition. Besides, 12-week Zumba dancing was not sufficient to significantly enhance cognitive performances (RT/WM) performances. These cognitive performances were related to postural control in challenging conditions and can be considered an effective tool for monitoring postural performances following an intervention program. Clinicians should, therefore, focus on interventions that boost cognitive functions in middle-aged women to achieve optimal postural control, mainly in challenging conditions, in order to prevent the risk and fear of falls as well as the incidence of falling. [ABSTRACT FROM AUTHOR]

In this study, we explored the immediate and three-month follow-up effects of physical training on physical fitness in children with autism spectrum disorder (ASD). We randomly assigned 20 children with ASD (age 8–11 years) into an experimental group (EG; n = 10) and a control group (CG; n = 10). The EG participated in an 8-week training program involving both strength and proprioceptive exercises (three 60-minute sessions/week), while the CG simply maintained their daily activities. We assessed physical fitness components for each participant at baseline, post-training, and at a 3-month follow-up. The physical training intervention significantly improved physical fitness of these children with ASD in terms of their flexibility (p <.001; 32.46%), lower limbs strength (p =.003; 36.98%), lower body power (p <.001; 41.78%) and functional mobility (p <.001; 25.56%). However, these addition training-induced gains were lost at follow-up for lower limbs strength (p <.001), flexibility (p <.001), and functional mobility (p =.034)). Physical training was effective for improving physical fitness in children with ASD, but the loss of these gains at three months follow-up underscored the need for continuous physical exercise. [ABSTRACT FROM AUTHOR]

Context: The Y Balance Test (YBT) is a simple, reliable, cost-effective screening test. It is used to evaluate dynamic balance as well as to determine the potential risk of injury of the lower limbs. The reliability of YBT has been widely reported in the general population. However, there are no studies evaluating the reliability of YBT use in athletes with intellectual disability (ID). The aim of the study was to examine the reliability of the YBT in runners with ID. Design: A reliability study. Methods: Twelve male runners (short-distance running) with ID (age 25.1 [4.50] y, height 169.1 [4.2] cm, weight 69.5 [5.5] kg, and intelligence quotient 60.8 [2.4]). The YBT was used to measure participants' dynamic balance in the anterior, posteromedial, and posterolateral reach directions. The analysis used the normalized values to the relative length of the lower limbs. A 1-way (trial) repeated-measures (5) analysis of variance for each direction was used. Intraclass correlation coefficient, standard error of measurement, and minimal detectable change were computed to assess the reliability of the YBT between trials. Results: After 6 practice trials, 3 out of 5 consecutive ones achieved results stabilization for all directions and both legs (P <.05). The intraclass correlation coefficient, standard error of measurement, and minimal detectable change values for all trials ranged from.76 to.87, 5% to <7%, and 11% to <15%, respectively. Conclusion: The YBT is a highly reliable tool to measure the dynamic balance of male runners with ID. Therefore, it is recommended to perform 6 practice trials and 3 measurements in these runners. [ABSTRACT FROM AUTHOR]

This study investigated the effect of verbal encouragement (VE) on static and dynamic balance in individuals with intellectual disabilities (IDs). A total of 13 mild IDs and 12 moderate IDs participants underwent static balance tests (bipedal stance on firm surface, under open eyes (OEs) and closed eyes (CEs), and foam surface, unipedal stance on firm surface) and dynamic balance assessments (Y Balance Test (YBT) and Expanded Timed Up-and-Go Test (ETUGT)) under VE and no VE (NO/VE) conditions. VE significantly reduced center of pressure mean velocity (CoPVm) values for mild IDs in firm bipedal CEs conditions. The mild IDs group exhibited improved YBT scores and enhanced ETUGT performances for both groups under VE. Incorporating VE as a motivational strategy in balance training interventions can positively impact static and dynamic balance in individuals with mild IDs, especially in challenging conditions like unipedal stances on firm surfaces. [ABSTRACT FROM AUTHOR]

Background: This study aims to investigate the impact of neuromuscular training (NMT) on static and dynamic postural balance (PB) among high‐level male runners with intellectual disability. Method: Twenty‐seven runners were randomly assigned to a NMT group and a control group who maintained their conventional training. Static and dynamic PB were assessed using the centre of pressure (CoP) excursions (in bipedal and unipedal stances under open eyes (OE) and closed eyes (CE) conditions) and the star excursion balance test (SEBT), respectively, at pre‐training and post‐training. Results: The NMT group showed significantly (p < 0.05) decreased CoP values and increased SEBT scores at post‐training compared to pre‐training. The switch from OE to CE did not affect static PB in the bipedal stance, only in the NMT group. Conclusions: The NMT was effective in improving static and dynamic PB in runners with intellectual disability. The NMT could reduce visual dependency. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of an 8-week aerobic dance intervention on postural balance in children. Forty-one children, aged 9 to 11, were randomly assigned to either an aerobic dance group (ADG) or a control group (CG) from a primary school. Postural balance was assessed using center of pressure (CoP) excursions before and after the 8-week intervention period. Evaluations were conducted on both firm and foam surfaces in bipedal and unipedal stances under open-eyes (OE) and closed-eyes (CE) conditions, as well as on both medial–lateral (ML) and anterior–posterior (AP) surfaces in a bipedal stance under OE conditions. The ADG exhibited significantly decreased CoPVm values during firm bipedal CE, unipedal OE, foam bipedal OE and CE, and foam unipedal OE (p < 0.005). This study suggests that aerobic dance intervention improved postural balance in children, showcasing adaptability and improved stability under various conditions. [ABSTRACT FROM AUTHOR]

We aimed to investigate 12-week-Zumba training effects on physical and psychological parameters, and quality of life (QoL) in postmenopausal women. Forty-two postmenopausal women were randomly allocated to a control group or a Zumba group (ZG). Postural balance, lower limb strength, mood level, and QoL were assessed before and after the 12-week-Zumba training. The ZG showed significantly better balance performances under all conditions such as on firm and foam surfaces with opened and closed eyes as well as improvements in limb strength, mood and QoL compared to their baselines. Thereby, 12-week-Zumba training was effective in improving postural balance, limb strength, mood and, QoL in postmenopausal women. [ABSTRACT FROM AUTHOR]

Static postural control disorders have been documented in soccer players suffering from groin pain (GP). Understanding the mechanisms of these disorders is crucial in designing rehabilitation programs. To (i) assess static postural control and core stability in soccer players suffering from GP compared to their peers and (ii) explore the relationship between these two parameters. This cross-sectional study involved 42 male soccer players suffering from GP (GP group: GPG) and 42 healthy players (control group: CG). Static postural control (stabilometric platform) and core stability (core endurance tests) were assessed. Center of pressure velocity in the GPG was significantly higher compared to the CG during bipedal stance on the firm surface with eyes closed (2.66 [95 % CI: 0.86–3.67]; p < 0.01) and on the foam one (p < 0.001) in both conditions; eyes opened (2.88 [95 % CI: 1.42–4.43]) and closed (5.88 [95 % CI: 2.66–9.10]), and on the IL in eyes closed (12.54 [95 % CI: 4.27–20.80]; p < 0.01). Besides, GPG revealed significant (p < 0.001) lower core stability measures compared to CG. No significant associations (p > 0.05) were observed between static postural control and core stability in GPG. Soccer players suffering from GP showed static disorders of postural control compared with their peers. These impairments were not associated with measures of core stability. These findings provide insight into the direction of future research exploring the mechanisms underlying deficits in static postural control in soccer players suffering from GP. • Players with groin pain had static postural balance disorders compared to controls. • Core stability was not associated with static balance performance in these players. • This provides insights for future studies into static balance disorders mechanisms. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the effect of beetroot juice supplementation (BEET) on neuromuscular fatigue etiology during simulated soccer match play. In a randomized, double-blind, crossover design, 13 soccer players completed the Loughborough Intermittent Shuttle Test (LIST). Players received either BEET (2×150 mL; ∼8 mmol/L nitrate) or placebo (PLA) for 7 days (6 days prior to the experimental session and on the day of trial, 2 h before LIST). Neuromuscular assessments were performed at baseline, 45 min (half time: HT), and 90 min (full time: FT) following LIST. Maximal voluntary contraction (MVC) and twitch responses, delivered through electrical femoral nerve stimulation, were used to assess peripheral (quadriceps resting twitch force Qtw,pot) and central fatigue (voluntary activation, VA). Compared with baseline, MVC Qtw,pot and VA values decreased in PLA and BEET conditions at HT and FT (P < 0.05). Compared with PLA, the decrease in MVC and Qtw,pot was significantly attenuated with BEET at HT and FT (P < 0.001). Likewise, BEET attenuated the decrease in VA at HT (P < 0.001, d = 1.3) and FT (P < 0.001, d = 1.5) compared with the PLA condition. Chronic beetroot juice supplementation attenuates neuromuscular fatigue development during simulated soccer matches, and this is due to both central and peripheral factors. Consequently, chronic beetroot may optimize physical performance. [ABSTRACT FROM AUTHOR]

The researchers aimed to examine the effect of 12-week supplementing (100 mg/day) caffeine with Zumba training on postural and cognitive performances in middle-aged women. Fifty-six middle-aged women who participated in this study, were randomized into; a caffeine-Zumba (CZG), Zumba (ZG) and control groups. In two-testing sessions, postural balance was evaluated using a stabilometric platform, and for cognitive performances, Simple Reaction Time and Corsi Block-Tapping Task tests were used. We found that ZG and CZG showed a significant improvement in postural balance on the firm surface condition (p <.05) in the post- compared to pretest session. Whereas, ZG showed no significant improvement in postural performance on the foam surface condition. Only CZG revealed significant enhancements (p <.05) in cognitive and postural, in the foam surface condition, performances. In conclusion, supplementing caffeine with 12-week Zumba training was effective in improving both cognitive and postural balance, even in challenging conditions, performances in middle-aged women. [ABSTRACT FROM AUTHOR]

Our study aimed to compare explosive performance and underlying mechanical determinants explored through F-V profiles in jumping and sprinting among young soccer players based on their playing position. Ninety elite soccer players were categorized into the following positions: goalkeepers, central defenders, wide defenders, central midfielders, wide midfielders, and forwards. Two testing sessions were conducted to measure the 30-metre sprint time (T30) using an over-ground sprint test and jump height (Hmax) through the SJ test. Results demonstrated performance variations among positions. In sprinting, forwards showed greater T30 (4.5 ± 0.14 s) compared to other positions, with goalkeepers exhibiting the lowest T30 (4.86 ± 0.18 s). Forwards also displayed higher maximal theoretical velocity (8.8 ± 0.4 m.s−1) and power output (Pmax) (19.4 ± 2.6 W.kg−1) than other positions, while goalkeepers had the lowest Pmax (16.5 ± 2 W.kg−1). In jumping, forwards (33.2 ± 3.9 cm) and wide-midfielders (33.6 ± 3.8 cm) achieved higher Hmax compared to goalkeepers (29.2 ± 5 cm) and central-midfielders (29.2 ± 3.8 cm). Wide-midfielders (28.5 ± 4.8 W.kg−1) and forwards (27.1 ± 4.3 W.kg−1) surpassed goalkeepers (23 ± 2.8 W.kg−1) and central-midfielders (25.1 ± 3.8 W.kg−1) in Pmax. Our findings reveal substantial position-related disparities in F-V profiles among elite young soccer players, in sprinting and jumping emphasizing the need for position-specific training programmes to optimize player development and on-field performance from an early age. [ABSTRACT FROM AUTHOR]

Context: Athletes with intellectual disability (ID) have a high risk of injury while participating in various sports. Warm-up (WU) is the most preventive measure to reduce injuries in sports. Objective: To investigate the effects of dynamic stretching WU (DS-WU) and plyometric WU (PL-WU) on dynamic balance in athletes with ID. Design: Crossover study. Setting: Research laboratory. Participants: A total of 12 athletes with ID (age 24.5 [3.22] y, height 165.7 [8.4] cm, weight 61.5 [7.1] kg, intelligence quotient 61.1 [3.5]). Main Outcome Measures: Dynamic balance was assessed using the Star Excursion Balance Test (SEBT) at pre-WU, post-WU, and 15 minutes post-WU for both the DS-WU and the PL-WU. A 2-way analysis of variance (3 sessions x 2 WU methods) with repeated-measures was used in this study. Results: Following the DS-WU, participants demonstrated significant improvements in the SEBT composite score post-WU (89.12% [5.54%] vs 87.04% [5.35%]; P<.01) and at 15 minutes post-WU (89.55% [5.28%] vs 87.04%, P < .01) compared with pre-WU. However, no significant difference between these two post-WU scores (post-WU and 15 min post-WU) was found. For the PL-WU, participants demonstrated a significant decrease in the SEBT composite score at post-WU (85.95% [5.49%] vs 87.02% [5.73%]; P<.05); however, these scores increased significantly at 15 minutes post-WU (88.60% [5.42%] vs 87.02% [5.49%]; P < .05) compared with that at pre-WU. The SEBT composite scores are significantly higher in the DS-WU than in the PL-WU at both post-WU sessions (P < .05). Conclusion: Both DS-WU and PL-WU could improve dynamic balance and may be recommended as WUs in athletes with ID; however, particular caution should be exercised immediately after the PL-WU. [ABSTRACT FROM AUTHOR]

Background: While there is ample evidence on the effects of single-mode aerobic and speed training on physical fitness in soccer players, less is known on the combined effects of these exercise regimens on physical and psychological factors. Aim: This study aimed to compare the effects of aerobic and speed training with soccer-specific training versus soccer-specific training only on aerobic performance during the YOYO intermittent fitness test level 1 (final velocity, total distance [TD], maximal oxygen consumption [VO2max]), repeated sprint ability (best, total sprint time [RSABT, RSATT], sprint decrement [RSA dec]) performance and somatic anxiety (SA), cognitive anxiety (CA), and self-confidence (SC) adaptations in soccer players. Methods: Thirty-eight highly trained male athletes aged 18.9 ± 0.5 years were randomly assigned to an aerobic and speed training group (COMB-G; n = 20) or an active control group (CON-G; n = 18). Aerobic training comprised intermittent exercises at 110–120% of the final velocity achieved at the end of the YOYO IL1 test. Speed training involved maximal sprints over 15–20-m with 5–6 sets per session. Aerobic or speed training lasted 20 min per session and replaced parts of the soccer-specific training. CON-G performed the soccer-specific training including technical, tactical drills and small-sided games. Training volume was similar between groups. Pre, post intervention, all participants performed a repeated-sprint ability (RSA) test, the YO-YO IL1 test and the players completed a Competitive Scale Anxiety Inventory (CSAI-2). Results: A two (group: COMB-G, CON-G) by two (time: pre, post) mixed ANOVA (group-by-time) was computed. Significant group-by-time interactions were found for RSATT (F = 117.3; p < 0.001; Pη2 = 1.78), RSABT (F = 82.4; p < 0.001; Pη2 = 1.53), final velocity (F = 85.8; p < 0.001; Pη2 = 1.53), TD (F = 87.1; p < 0.001; Pη2 = 1.56), and VO2max (F = 18.0; p < 0.001; Pη2 = 0.72). In addition, significant group-by-time interactions were observed for SC (F = 90.2; p < 0.001; d = 1.60), SA (F = 60.5; p < 0.001; Pη2 = 1.70), and CA (F = 20.7; p < 0.001; Pη2 = 0.75). Post-hoc analyses indicated significant improvements for all dependent variables from pre- to post-training in favor of COMB-G. Conclusion: Aerobic and speed training in combination with soccer-specific training is a safe and effective training method as it exerts positive effects not only for physical fitness but also for self-confidence and the coping of anxiety in male soccer players. [ABSTRACT FROM AUTHOR]

Postmenopausal women suffer from postural balance issues. During a 24-hour time span, postural performance undergoes radical changes as influenced by the circadian rhythm. In this study, we aimed to investigate time-of-day effects on postural balance in postmenopausal women and balance relationships with menopausal symptoms. Two groups of women, aged 40–50 years, participated in this study: a menopausal group and a control group. We evaluated their postural balance and menopausal symptoms (mood, sleepiness and fatigue) in five sessions over the course of a day: at 06:00 hours, at 10:00, at 14:00, at 18:00 and at 22:00. The results showed that postural balance (center of pressure area (CoParea)) values of postmenopausal women were significantly worse (p <.05) at 22:00. Moreover, at this time-of-day, participants in the menopausal group were more tired, less vigilant and experienced a lower mood. We found negative correlations between postural balance and both mood and fatigue levels. However, there was no time-of-day effect on postural balance, mood, fatigue, and sleepiness among participants in the control group. Thus, time-of-day should be considered a factor to control when assessing postural balance and designing intervention studies for postmenopausal women; and it is important for these women to be cautious of fall risks at night, as they are then less stable than at other times-of-day. [ABSTRACT FROM AUTHOR]

Background: This study compared the acute effects of aerobic (AE) and resistance (RE) exercise on reaction time (RT) and working memory (WM) in individuals with intellectual disability. Methods: RT tests and Corsi test for WM were performed before and after three intervention sessions: AE, RE, or control session consisting on watching video. Results: The RT values decreased significantly (p <.001) after both of AE and RE with higher extend after the RE but did not vary following the control session. Corsi scores increased significantly (p <.001) after AE but not after RE or control session. Conclusions: These findings suggest that the effects of acute exercise on cognitive function in individuals with intellectual disability depend on the exercise mode as well as the nature of the cognitive task. The RE seems to be more recommended for RT enhancement whereas only the aerobic one could improve WM in these individuals. [ABSTRACT FROM AUTHOR]

Hammami, R, Duncan, MJ, Nebigh, A, Werfelli, H, and Rebai, H. The effects of 6 weeks eccentric training on speed, dynamic balance, muscle strength, power and lower limb asymmetry in prepubescent weightlifters. J Strength Cond Res 36(4): 955-962, 2022-This study examined whether 6 weeks of twice-weekly in-season hamstring eccentric training would enhance selected performance-related abilities in prepubescent male weightlifters. Twenty elite weightlifters (11.1 +/- 0.8 years) were randomly split into an eccentric training intervention group (INT n = 10) or a control group (CON) that maintained their standard in-season regimen (n = 10). Pre-intervention and postintervention speed, dynamic balance, muscle strength, power, and lower limb (LL) asymmetry were assessed. Analysis of covariance controlling for maturation was used to determine any differences in the performance variables. There were no significant changes in muscle strength, dynamic balance, or LL asymmetry (all p < 0.05) because of the intervention. Both 10-m (p = 0.001) and 30-m (p = 0.007) sprint speed and agility (p = 0.049) improved to a greater extent in INT compared with the CON group. Similar results were evident for the standing long jump (p = 0.015) and 3 hop test (p = 0.004) where performance improved to a greater magnitude in INT compared with CON groups. This study suggests that eccentric training, undertaken twice weekly for 6-weeks results in positive changes in sprint speed, change of direction speed, and power performance, but not muscle strength, dynamic balance, or LL asymmetry in prepubertal weightlifters. [ABSTRACT FROM AUTHOR]

Background: Previous reports showed that athletes without disabilities have better postural skills than their sedentary peers. This finding has not been elucidated in athletes with intellectual disabilities despite their decreased postural balance. This study aims to investigate static postural balance in track and field athletes with intellectual disabilities compared to their sedentary peers. Methods: Eighteen track and field athletes with intellectual disabilities (23.5 ± 4.52 years) and 18 sedentary peers (20.3 ± 3.4 years) participated in this study. A stabilometric platform was used to assess static postural balance in bipedal and unipedal stances with open (OE) and closed (CE) eyes. Results: In OE, the result showed significantly better static postural balance (CoPVm: p <.001; CoParea: p <.001) in athletes compared to the sedentary ones in both stances. In CE, this difference was not observed in the unipedal stance. Conclusion: Track and field experience may improve static postural balance in athletes with intellectual disabilities, mainly when visual input is available. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the existence of a critical threshold beyond which peripheral fatigue would not further decrease during knee extensor (KE) exercise in older men, and the consequences of this mechanism on the force-duration relationship. Twelve old men (59 ± 2 years) randomly performed two different sessions, in which they performed 60 maximum voluntary contractions (MVC; 3s contraction, 2s relaxation). One trial was performed in the unfatigued state (CTRL) and one other following fatiguing neuromuscular electrical stimulation of the KE (FNMES). Peripheral and central fatigue were quantified via pre/post-exercise decreases in quadriceps twitch-force (Δ Ptw) and voluntary activation (ΔVA). Critical torque (CT) was determined as the mean force of the last 12 contractions while W′ was calculated as the area above CT. Compared with CTRL, pre-fatigue (Δ Ptw = −10.3 ± 6.2%) resulted in a significant (p < 0.05) reduction in W' (−18.2 ± 1.6%) in FNMES. However, CT (∼964 N), ΔVA (∼15%) and Δ Ptw (∼25%) post-MVCs were similar between both conditions. In CTRL, W' was correlated with Δ Ptw (r2 = 0.78). Moreover, the difference in W' between CTRL and FNMES was correlated with the level of pre-fatigue induced in FNMES (r2 = 0.76). These findings document that peripheral fatigue is confined to an individual threshold during KE exercise in older men. Furthermore, correlative results suggest that mechanisms regulating peripheral fatigue to a critical threshold also restrict W', and therefore play a role in exercise capacity in older men. [ABSTRACT FROM AUTHOR]

Aim: To evaluate bone mass in female basketball players and the relationship between bone mineral density (BMD) and isokinetic muscle strength. Methods: We investigated 29 female basketball players, age 21.9 ± 9.1 years, training for about 6-8 hours per week. The reference group consisted of 22 non-active female, age 21.4 - 1.5 years. BMD was measured using dual-energy-X-ray absorptiometry in total body, lumbar spine, the whole femur and humerus. Isokinetic peak torque of the quadriceps and hamstring muscles were measured at 60 and 180°/s. Osteocalcin (OC) and cross-linked C-telopeptide (CTX) were measured by radioimmunoassay and electrochimiluminescence, respectively. Results: Compared to the controls, the basketball group had significantly (P <0.001) a higher BMD in the total body (11.6%), the lumbar spine (9.83%), the dominant femur (16.8%), the non-dominant femur (15.8%) and the dominant humerus (8.47%). The female basketball players had also significantly higher peak torques at both isokinetic velocities (60 and 180°/s) and for both lower limbs. All muscle peak torque measured for the female basketball players were significantly correlated with correspondent leg BMD and for both velocities tested. However, no significant correlations were noted for the control group. Values of formation (OC) and resorption (CTX) markers were significantly higher in the athletic females (P < 0.01 and P < 0.05, respectively). Conclusion: Our results show clearly that practice of basketball is associated with the improvement of bone mass. In addition, the most important finding of our study is that isokinetic muscle strength seems to be correlated with correspondent BMD in female basketball players. [ABSTRACT FROM AUTHOR]

This study aimed at quantifying maximal voluntary force-generating capacity of the quadriceps femoris and its EMG output after an isokinetic concentric intermittent exercise. Another objective was to find out whether the amount of neuromuscular fatigue was velocity-dependent. Eight males judo players (age: 18.4 ± 1.4 years; height: 1.80 ± 0.03 m; body mass: 77.0 ± 4.2 kg) performed a fatiguing exercise composed of five sets of ten maximal knee extension at 120°/s, with 3min recovery in between. Peak torque (PT) at three angular velocities (60, 120 and 180°/s) and EMG from the vastus lateralis, rectus femoris and vastus medialis were evaluated before and after the fatiguing exercise. EMG was analyzed for root mean square (RMS) and median frequency (MF). The fatiguing exercise induced PT decrement (P< 0.01) irrespective of the test velocity, in conjunction with decreased RMS (P< 0.001) and a decrease in MF (P< 0.01). In addition, although EMG activity demonstrated no velocity effect, the loss of PT after the fatiguing isokinetic intermittent exercise was more pronounced at the lower velocity (P< 0.05). The combination of decreased PT, RMS and MF suggests a reduction of the neural drive under the present fatiguing protocol. [ABSTRACT FROM AUTHOR]