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The present study was designed to assess time-of-day effects on postural balance and symptoms of rheumatoid arthritis (RA) patients. A total of 15 American College of Rheumatology functional class I and II RA patients and 15 healthy controls aged between 45 and 55 (mean age: 50 ± 3) years of age voluntarily participated. We conducted a case-control, repeated-measures in design study. Postural balance, axillary temperature, pain intensity, fatigue, and sleepiness were measured during five test sessions at 06:00, 10:00, 14:00, 18:00, and 22:00 h. Participants were randomized to the order of test sessions, and each session was separated by >36 hours to minimize/eliminate learning effects. Center of pressure area (CoParea) (p

Summary Objectives The purpose of the present study is to explore the characteristics of the postural control in Kung-Fu trained young boys, in comparison with non-trained age-matched ones. Material and methods Two groups of 11–13-year old boys (10 practicing Kung-Fu and 10 controls) were asked to maintain upright bipedal and unipedal stances on a force platform with eyes open and closed in a static and two dynamic postures. Postural control was assessed with centre of pressure excursions. Muscle response characteristics were recorded during maintaining a bipedal stance on an unstable platform with eyes open and closed. Results Kung-Fu practitioners had significantly (P Conclusions Kung-Fu trained young boys seems to have better postural control in dynamic (unipedal-eyes open and bipedal-eyes closed) postures and better neuromuscular responses compared to non-trained ones.

BACKGROUND This study explored the effect of running exercises at low [30% heart rate reserve (HRR)] and moderate (60%HRR) intensities on cognitive performances in individuals with intellectual disability (ID). METHODS Participants performed randomly reaction time (RT) tests: visual RT [simple RT (SRT) and choice RT (CRT)], auditory SRT (ASRT) and working memory (WM) (Corsi test) before and after the exercises. RESULTS The results showed that after both exercises, SRT decreased significantly (P

Graja, A, Kacem, M, Hammouda, O, Borji, R, Bouzid, MA, Souissi, N, and Rebai, H. Physical, biochemical, and neuromuscular responses to repeated sprint exercise in eumenorrheic female handball players: effect of menstrual cycle phases. J Strength Cond Res 36(8): 2268-2276, 2022-Very few studies have been interested in the relationship between ovarian hormones and physiological function in female athletes. The aim of this study was to assess the effect of menstrual phases (MP) on physical, neuromuscular, and biochemical responses after repeated sprint exercise (RSE) in female handball players. Ten eumenorrheic athletes (22.5 ± 1.5 years, 1.70 ± 0.04 m) participated in 3 study visits (follicular phase [FP], luteal phase [LP], and premenstrual phase [PMP]). During each MP, they performed 20 × 5-second cycle sprints interspersed with 25 seconds of rest. Maximal voluntary contraction (MVC) tests of the knee extensor muscles at 90° of knee flexion were performed before and after RSE. Peak force and electromyography (EMG) signals were measured during the MVC tests. Blood samples were collected before and 3 minutes after each session. The percentage of decrement in peak power output over the 20 × 5-second cycle test (i.e., fatigue index) calculated between sprints 1 and 20 decreased significantly during PMP (-43.3% ± 5.7%) but not in LP (-39.2% ± 7.7%) compared with FP (-32.44% ± 6.3%) ( p0.05). Moreover, no significant difference was found between MP in all frequency components of EMG before RSE ( p0.05). Maximal voluntary contraction, neuromuscular efficiency, and median frequency values of vastus lateralis and rectus femoris were significantly decreased in PMP compared with FP and LP ( p0.05). Creatine kinase (CK) levels were significantly higher in PMP compared with FP and LP after RSE ( p0.05). These findings suggest that RSE induces more peripheral fatigue associated with muscle damage in PMP. This might be attributable to hormonal variation across MP. Therefore, FP seems to be the right time for intense training to improve strength performance.

This study explored the fatigue effect on postural control (PC) across menstrual cycle phases (MCPs) in female athletes. Isometric maximal voluntary contraction (IMVC), the center of pressure sway area (CoParea), CoP length in the medio-lateral (CoPLX) and antero-posterior (CoPLY) directions, and Y-balance test (YBT) were assessed before and after a fatiguing exercise during the follicular phase (FP), mid-luteal phase (LP), and premenstrual phase (PMP). Baseline normalized reach distances (NRDs) for the YBT were lower (p = 0.00) in the PMP compared to others MCPs, but the IMVC, CoParea, CoPLX, and CoPLY remained unchanged. After exercise, the IMVC and the NRD decrease was higher at PMP compared to FP (p = 0.00) and LP (p = 0.00). The CoParea, CoPLX, and CoPLY increase was higher in the PMP compared to FP (p = 0.00) and LP (p = 0.00). It was concluded that there is an accentuated PC impairment after exercise observed at PMP.

Objective: This study explored the time of day effect of balance performance, functional capacities and risk of fall in three different times in patients with rheumatoid arthritis (RA) and the association between these variations and those of RA symptoms.Methods: A "discontinual" protocol, composed of three test sessions, carried out at 6 am, 2 pm and 10 pm was set up, in order to investigate the time of day effect of balance performance, functional capacities, risk of fall, stiffness, range of motion, swollen and painful joints in women with RA.Results: Time Up and Go Test (TUGT), Functional Reach Test (FRT) and tinetti test scores were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. Stiffness, range of motion, swollen and painful joints values were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. A significant difference was observed on the stiffness, range of motion and swollen joints values between 6 am and 10 pm that were higher at 6 am (p < .05).Using Pearson's coefficient, correlations were found between RA symptom values; and TUGT, FRT and Tinetti test scores.Conclusion: Results showed a time of day effect of balance performance, functional capacities and risk of falls in women with RA. This variation indicates an alteration of performance at 6 am and 10 pm. Fluctuations of stiffness, limited range of motion, swollen and painful joints noted are concomitant to those of balance performance, functional capacities, and risk of fall.Abbreviations: RA: rheumatoid arthritis; HO PSQI: Pittsburgh sleep quality index; HAQ: health assessment questionnaire; SF-36: the short form-36; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; TUGT: Time Up and Go Test; FRT: Functional Reach Test.

Fathi, A, Hammami, R, Moran, J, Borji, R, Sahli, S, and Rebai, H. Effect of a 16-week combined strength and plyometric training program followed by a detraining period on athletic performance in pubertal volleyball players. J Strength Cond Res 33(8): 2117-2127, 2019-The purpose of this study was to determine the effects of 16 weeks of combined strength and plyometric training or plyometric training alone and how a detraining program can modify adaptations in response to the training stimulus. Sixty male volleyball players (circa peak-height-velocity [PHV]: -1 to +1 year from PHV) were assigned to a combined training group (CTG) (n = 20), a plyometric training group (PTG) (n = 20), or a control group (n = 20). The experimental groups (CTG and PTG) participated in training twice weekly for 16 weeks. Thigh muscle volume, body fat, flexibility, sprint, jump height, and medicine ball throw were measured before and after the intervention and after the period of detraining. Respectively, the CTG and PTG showed increases in thigh muscle volume (effect size: 0.71 and 0.42) and decreases in body fat (-0.42 and -0.34), as well as improvements in 5-m sprint (-0.69 and -0.46), 10-m sprint (-0.31 and -0.3), lower-body muscle power (0.44 and 0.36), and upper-body muscle power (1.32 and 0.7). After the detraining period, all groups maintained previously attained muscle power (6.79-9.87%; p < 0.001). In conclusion, combined strength and plyometric training provided better improvements than plyometric training only. The combination of strength and plyometric training is a time-effective training modality that confers improvements in physical performance measures, muscle size, and body fat. A temporary period of detraining may not undermine performance gains in pubertal volleyball players.

The authors explored neuromuscular fatigue in athletes with intellectual disability (AID) compared with sedentary individuals with intellectual disability (SID) and individuals with typical development. Force, voluntary activation level, potentiated resting twitch, and electromyography signals were assessed during isometric maximal voluntary contractions performed before and immediately after an isometric submaximal exhaustive contraction (15% isometric maximal voluntary contractions) and during recovery period. AID presented shorter time to task failure than SID (p p p p

In Parkour activity, the aim is to move from one place to another as quickly and efficiently as possible by running, climbing, swinging, vaulting, rolling, crawling and jumping on tiny obstacles … . Performing these actions places a great demand on the postural control system. The purpose of the present study was to investigate postural control of Parkour practitioners - called Traceurs - compared to recreationally active (RA) subjects in different postural conditions after manipulating the visual and/or proprioceptive sensory inputs. Ten Traceurs (mean experience 5.9 ± 0.9 years;5 hours per week) and 10 RA subjects participated in this study. We measured the centre of pressure area (CoP

Physical-cognitive interventions seem promising to improve balance and gait performances and prevent falls in the elderly. Although these beneficial effects, it is still not clear whether these physical-cognitive training modalities leads to more general non-specific adaptations that can be transferred to some measures reflecting every day abilities. This randomized controlled trial examined postural (center of pressure oscillations), physical (lower body strength, gait speed, functional mobility, dynamic balance) and cognitive performances (reaction time) and postural performance during daily life tasks (walking while conversing on a phone and maintaining an upright standing posture while buttoning a shirt) in older adults (66.29±3.61years) pre- and post- 6-months physical and physical-cognitive interventions. Results showed that both training modalities improve balance (p

Cell phone use is considered as an essential part of everyday life saturating all age groups and demographics. This study aimed to explore the effect of various cell phone functions on postural control and mobility in the elderly. Twenty healthy older (mean age 72.5±2.9) and twenty young (26.3±2.8) adults participated in this study. Postural balance was assessed by measuring the center of pressure (CoP) displacement with (talking on a cell phone (CONVERSE), dialing a number (DIAL) and listening to music (MUSIC)) and without cell phone use. Mobility was assessed by the Timed Up and Go Test (TUGT). Results showed that for both groups, the CoP parameters increased significantly during the CONVERSE (p

The aim of the present study was to investigate the effects of Ramadan intermittent fasting (RIF) on the underlying mechanisms of force production capacity during maximal voluntary isometric contraction (MVIC) using the superimposed twitch technique. Ten healthy male physical education students performed three MVIC of the knee extensor superimposed with nerve electrical stimulation during four testing phases: one week before Ramadan (BR), at the end of the first week of Ramadan (R-1), during the fourth week of Ramadan (R-4) and two weeks after Ramadan (AR). This study was performed during Ramadan 2016. MVIC values, voluntary activation level (VAL), potentiated resting twitch and electromyography signals were recorded during each MVIC. The French version of the Profile of Mood States questionnaire (POMS-f) was used to evaluate the subjective mood states in each testing session. The results showed that MVIC values (890.57 ± 67.90 vs. 816.46 ± 54.72 N) and VAL (87.73 ± 3.27 vs. 77.32 ± 7.87%) decreased at R-1 compared to BR (p0.001). However, the neuromuscular efficiency and the potentiated resting twitch remained unchanged during Ramadan (R). Results showed that depression (p0.01; 6.3 ± 1.57 vs. 4.7 ± 1.25), fatigue (p0.001; 9.2 ± 1.93 vs. 4.6 ± 2.01) and anxiety (p0.001; 6.4 ± 1.51 vs. 11.8 ± 1.23) scores of POMS-f were higher during R-1 compared to BR. In conclusion, RIF-related impairment of maximal muscle force seems to be related to nervous alterations of the VAL, whereas the RIF did not adversely affect peripheral mechanisms. Abbreviations' List: ANOVA: Analysis of variance; AR: After Ramadan; BMI: Body-mass index; BR: Before Ramadan; EMG: Electromyography; ER: End of Ramadan; MF: Mean frequency; M

Background This study aimed to compare the effectiveness of a hopping and jumping training programme (HJP) versus a sensorimotor rehabilitation programme (SRP) on postural performances in children with intellectual disability. Methods Three groups of children with intellectual disability participated in the study: the HJP group, the SRP group and a control group. Postural capacities were tested with the Berg Balance Scale (BBS) and the Tinetti tests. The HJP and the SRP groups participated in the training programmes for eight weeks. Then, all participants were retested. Results Results showed that before the training period, there are no significant differences between the three groups. After the training period, the BBS and the Tinetti scores increased significantly in the HJP group and the SRP group with greater extent in the HJP group than in the STP group. Conclusion We suggest that HJP training is more recommended to improve postural capacities in children with intellectual disability.

This study aimed to explore the effect of local muscle fatigue on the unipedal stance in men with intellectual disability (ID). The Centre of pressure (CoP) excursions and the isometric maximal voluntary contraction (MVC) were measured before and after a fatiguing exercise. Higher baseline values of CoP excursions and lower MVC values were recorded in the ID group. After the fatiguing exercise, this group showed higher MVC decrease and higher percentage of increase of the mean CoP velocity. In conclusion, men with ID are more vulnerable to the disturbing effects of fatigue during the unipedal stance compared to men without ID.

The aim of our study was to investigate the effect of a combined strength and proprioception training (CSPT) program on muscle strength and postural balance in children with intellectual disability (ID). The maximum voluntary contraction (MVC) and postural parameters (CoPVm, CoPLX, CoPLY) of 20 children with ID were recorded before and after 8 weeks of a CSPT program. The participants were divided into two groups: an experimental group who attended a CSPT program and a control group who continued with daily activities. In the trained group, the MVC increased significantly (p

BACKGROUND This study aimed to explore muscle strength production and its underlying neuromuscular characteristics in sedentary and trained individuals with intellectual disability (ID) compared with healthy sedentary individuals. METHODS Three adult groups (age: 25.07 ± 0.70) consisting of sedentary individuals with ID (IDSG), trained individuals with ID (IDTG) and a control group (CONT) participated in the present study. Peak torque (PT) during maximal voluntary isometric contraction, voluntary activation level (VAL), surface electromyography (sEMG) recordings, electrophysiological (Mmax ) and potentiated twitch torque (PTT responses) of the knee extensor muscles and thigh muscle volume were assessed. RESULTS Compared with CONT and IDTG, respectively, IDSG presented significantly lower PT (-48% and -42%), VAL (-24% and -9%), sEMG (-49% and -29%), Mmax (-41% and -39%) and PTT (-32% and -28%) values. These deficits were reduced between IDTG compared with CONT (i.e. PT: -10%; VAL: -16%; and sEMG: -28%) or did not differ anymore (PTT and Mmax ). Normalising PT to thigh muscle volume and/or computing theoretical PT value overwhelm strength production differences between IDTG and CONT. Training background influences the outcomes with IDTG exhibiting greater PT, VAL, sEMG, Mmax and PTT than IDSG. CONCLUSIONS Strength production deficit in IDSG was related to both muscular and neural characteristics compared with healthy controls whereas this deficit mainly arises from neural characteristics for IDTG.

Background The purpose of the current study was to evaluate the effects of dual-task (DT) constraints on walking performance in children with intellectual disability (ID). Methods Fifteen children with intellectual disability and fifteen age-matched typically developed children were asked to walk at a preferred speed: along a path (baseline condition), while carrying a glass of water and while quoting animal names. Results The present study findings showed that DTs affect walking performance of both typically developed children and those with intellectual disability. In children with intellectual disability, DT walking decrements were significantly higher when performing a concurrent motor task than cognitive one. Conclusions DT constraints with a secondary motor or cognitive tasks seemed challenging for children with intellectual disability suggesting that future treatments or assessments should consider using DT constraints to manipulate the difficulty of tasks.

To evaluate the effects of Ramadan fasting on postural balance and attentional capacities in older adults. the Neurophysiology department of a University Hospital. Fifteen males aged between 65 and 80 years were asked to perform a postural balance protocol and a simple reaction time (SRT) test in four testing phases: one week before Ramadan (BR), during the second (SWR) and the fourth week of Ramadan (FWR) and 3 weeks after Ramadan (AR). Postural balance measurements were recorded in the bipedal stance in four different conditions: firm surface/eyes open (EO), firm surface/eyes closed (EC), foam surface/EO and foam surface/EC using a force platform. Results of the present study demonstrated that center of pressure (CoP) mean velocity (CoPVm), medio-lateral length (CoPLX) and antero-posterior length (CoPLY) were significantly higher during the SWR than BR. Likewise, values of CoPVm and CoPLX increased significantly during the FWR compared to BR. The CoPLX decreased significantly in the FWR compared to the SWR. Values of CoPVm and CoPLX were significantly higher AR in comparison with BR. In addition, SRT values increased significantly during the SWR and the FWR than BR. Ramadan fasting affects postural balance and attentional capacities in the elderly mainly in the SWR and it may, therefore, increase the risk of fall and fall-related injuries. More than three weeks are needed for older adults to recover postural balance impairment due to Ramadan fasting.

The aim of this study was to examine the relationship between bone mass and bone turnover markers with lean mass (LM) in pubescent soccer players. Two groups participated in this study, which included 65 elite young soccer players who trained for 6–8 hours per week and 60 controls. Bone mineral density; bone mineral content in the whole body, lower limbs, lumbar spine, and femoral neck; biochemical markers of osteocalcin; bone-specific alkaline phosphatase; C-telopeptide type I collagen; and total LM were assessed. Young soccer players showed higher bone mineral density and bone mineral content in the whole body and weight-bearing sites (P P r = .29; r = .31; P

Purpose: This study aimed to explore neuromuscular fatigue and recovery profiles in individuals with intellectual disability (ID) after exhausting submaximal contraction. Methods: Ten men with ID were compared to 10 men without ID. The evaluation of neuromuscular function consisted in brief (3 s) isometric maximal voluntary contraction (IMVC) of the knee extension superimposed with electrical nerve stimulation before, immediately after, and during 33 min after an exhausting submaximal isometric task at 15% of the IMVC. Force, voluntary activation level (VAL), potentiated twitch (Ptw), and electromyography (EMG) signals were measured during IMVC and then analyzed. Results: Individuals with ID developed lower baseline IMVC, VAL, Ptw, and RMS/Mmax ratio (root-mean-square value normalized to the maximal peak-to-peak amplitude of the M-wave) than controls (p

Our purpose was to compare the effects of Ramadan fasting on postural control in elderly fallers and non-fallers. The protocol involved twenty-four healthy old volunteer males divided into two groups: fallers (mean age = 75.43 ± 5.26 years, weight = 67.25 ± 5.30 kg and height = 1.65 ± 0.02 m) and non-fallers (mean age = 72.3 ± 6.42 years, weight = 65.5 ± 6.15 kg and height = 1.64 ± 0.03 m). Participants performed a simple reaction time test (SRT) and a postural control protocol on four different occasions: one week before Ramadan (BR), during the second (SWR) and the fourth week (FWR) of Ramadan and three weeks after Ramadan (AR). Center of pressure (CoP) parameters [the CoP medial-lateral length (CoPX), and the CoP antero-posterior length (CoPY)] were assessed using a force platform under two surface conditions: Firm surface and Foam surface. The results showed that Ramadan fasting influences similarly fallers and non-fallers. In fact, for both groups, the CoPX and the CoPY values increased significantly during the SWR and the FWR compared to BR. These CoP parameters decreased significantly in the Firm surface conditions in the FWR. Moreover, the CoP parameters were significantly higher during the FWR and AR in comparison with BR in the Foam surface conditions. However, the amplitude of increase of the CoP[X] % and the CoP[Y] % (ΔCoP[X] % and ΔCoP[Y] %) between BR and the SWR was significantly higher in the fallers than non-fallers. The SRT of elderly fallers and non-fallers was significantly higher in the SWR and in the FWR compared to BR. In conclusion, Ramadan fasting alters similarly postural control of elderly fallers and non-fallers, but the amplitude (ΔCoP[X] % and ΔCoP[Y] %) of this alteration seems to be more pronounced in fallers than non-fallers. A probable beginning of adaptation occurs at the FWR. However, three weeks seems to be insufficient to recover postural control alterations due to Ramadan fasting in difficult sensory conditions in elderly fallers and non-fallers.

The aim of this study was to explore the voluntary activation level during maximal voluntary contraction (MVC) in individuals with intellectual disability (ID) versus individuals without ID using the twitch interpolation technique. Ten individuals with mild ID (ID group) and 10 sedentary men without ID (control group) participated in this study. The evaluation of neuromuscular function consisted in three brief MVCs (3s) of the knee extension superimposed with electrical nerve stimulation (NES) to measure voluntary activation. Muscle activity levels were also measured with surface EMG. The root mean square (RMS) was extracted from the EMG signal. The RMS/Mmax ratio and the neuromuscular efficiency (NME) were calculated. Our results reported that individuals with ID present lower muscle strength (p < 0.001), lower voluntary activation level (p < 0.001), lower RMS values of vastus lateralis (p < 0.05), vastus medialis (p < 0.05), and rectus femoris (p < 0.001) muscles. In addition, our results showed lower RMS/Mmax values in the ID group than in the control group for the VM (0.05 ± 0.01 mV vs. 0.04 ± 0.01 mV; p < 0.05) and the RF (0.06 ± 0.02 mV vs. 0.05 ± 0.02 mV; p < 0.05) muscles. However, no significant difference was reported for the VL muscle (0.05 ± 0.02 mV vs. 0.05 ± 0.02 mV; p=0.463). Moreover, Individuals with ID present smaller potentiated twitch (p < 0.001). However, no significant difference was reported in the NME ratio. These results suggest that the lower muscle strength known in individuals with ID is related to a central nervous system failure to activate motor units and to some abnormal intrinsic muscle properties. It seems that the inactive lifestyle adopted by individuals with ID is one of the most important factors of their lower voluntary activation levels. Therefore, physical activities should be introduced in life style of individuals with ID to improve their neuromuscular function.

This study examined neuromuscular fatigue after high-intensity intermittent exercise in 10 men with mild intellectual disability (ID) in comparison with 10 controls. Both groups performed three maximal voluntary contractions (MVC) of knee extension with 5 min in-between. The highest level achieved was selected as reference MVC. The fatiguing exercise consists of five sets with a maximal number of flexion-extension cycles at 80% of the one maximal repetition (1RM) for the right leg at 90° with 90 s rest interval between sets. The MVC was tested again after the last set. Peak force and electromyography (EMG) signals were measured during the MVC tests. Root Mean Square (RMS) and Median Frequency (MF) were calculated. Neuromuscular efficiency (NME) was calculated as the ratio of peak force to the RMS. Before exercise, individuals with ID had a lower MVC (p0.05) and a lower RMS (p0.05). No significant difference between groups in MF and NME. After exercise, MVC decreases significantly in both groups (p0.001). Individuals with ID have greater force decline (p0.001 vs. p0.01). RMS decreased significantly (p0.001) whereas the NME increased significantly (p0.05) in individuals with ID, but both remained unchanged in controls. The MF decreased significantly in both groups (p0.001). In conclusion, individuals with ID presented a lower peak force than individuals without ID. After a high-intensity intermittent exercise, individuals with ID demonstrated a greater force decline caused by neural activation failure. When rehabilitation and sport train ID individuals, they should consider this nervous system weakness.