Effects of a nighttime melatonin ingestion on dynamic postural balance and muscle strength the following morning in people living with multiple sclerosis: A preliminary study.

BACKGROUND: Decreased endogenous melatonin concentrations in people with multiple sclerosis (PwMS) are associated with fatigue and pain that impair postural balance and muscle strength. Melatonin ingestion had analgesic and anti-fatigue effects. However, the acute effect of exogenous melatonin on dynamic postural stability and muscle strength has not been studied yet in PwMS. This study aimed to investigate the safety and the efficacy of a nighttime melatonin intake on dynamic postural balance and lower-extremity muscle strength the following morning in PwMS. METHODS: Fourteen PwMS (28.36 ± 6.81 years) were assessed (8 a.m.) pre- and post-acute intake of melatonin or placebo (6mg, 30 minutes before nocturnal bedtime). Evaluated parameters included dynamic postural balance (force platform), lower-extremity muscle strength [Five-Repetition Sit-To-Stand Test (5-STST)], hand dexterity (Nine-Hole Peg Test), nociceptive pain [Visual Analogue Scale (VAS)], neuropathic pain [Neuropathic Pain 4 Questions (DN4)], sleep quality and fatigue perception [Hooper Index (HI)]. RESULTS: In the frontal plane, melatonin reduced the center of pressure (CoP) path length (CoPL), CoPL in the anteroposterior axis (CoPLY) and CoP sway area (CoPAr) compared with placebo by 7.56% (p=0.02, Cohens'd (d)=1.24), 19.27% (p<0.001, d=2.60) and 13.82% (p<0.001, d=2.02), respectively. Melatonin induced a higher decrease in these posturographic parameters compared with placebo in the sagittal plane [CoPL: 9.10% (p=0.005, d=1.02), CoPLY: 4.29% (p=0.025, d=1.07) and CoPAr: 7.45% (p=0.038, d=0.74)]. Melatonin decreased 5-STST duration as well as VAS, DN4, HI-fatigue and HI-sleep scores compared with placebo by 8.19% (p=0.008, d=1.19), 5.74% (p=0.04, d=0.82), 27.30% (p=0.023, d=0.98), 40.15% (p=0.044, d=0.85) and 30.16% (p=0.012, d=1.10), respectively. CONCLUSION: This preliminary study, among PwMS, showed that acute melatonin ingestion was safe and efficient for improving dynamic postural stability and lower-extremity muscle strength probably through its analgesic and anti-fatigue effects.

Combined effect of gender differences and fatiguing task on postural balance, functional mobility and fall risk in adults with multiple sclerosis: A preliminary study.

AIM: To investigate the gender difference effect on postural balance, functional mobility, and fall risk after performing a fatiguing task in adults with multiple sclerosis (MS). METHODS: Eleven women (30.91 ± 8.19 years) and seven men (30.29 ± 7.99 years) with relapsing-remitting MS performed a fatiguing task: three sets of the Five-repetition Sit-To-Stand Test (5-STST) were performed before and after the six-minute WalkTest (6MWT). Bipedal postural balance in eyes open and eyes closed conditions were assessed prefatigue (T0) and postfatigue (T3) using a force platform. Unipedal balance, functional mobility (Timed Up and Go Test), fall risk (Four Square Step Test) and fatigue [Visual Analogue Scale of Fatigue (VASF)] were assessed at T0 and T3. Heart rate (HR) and Rating of Perceived Exertion (RPE) were recorded before (only for HR), during and after the fatiguing task. RESULTS: Compared to women, men showed an impairment of posturographic parameters [mean center of pressure (CoP) velocity (CoPVm) in both conditions (p < 0.05); CoP sway area (CoPAr) in both conditions (p < 0.01)], unipedal balance on the dominant leg (p <0.001), mobility (p<0.001) and an increased fall risk (p < 0.05). No gender differences were observed in 6MWT, 5-STST, HR, RPE, and VASF. CONCLUSION: This preliminary study showed that fatiguing task negatively affected postural control, mobility and fall risk only in men. These gender differences were inconclusive but could be taken into account in postural balance rehabilitation programs for MS persons.

Effect of melatonin intake on postural balance, functional mobility and fall risk in persons with multiple sclerosis: a pilot study.

AIM: To assess the safety and the effect of a nocturnal melatonin (MEL) ingestion on postural balance, functional mobility and fall risk the following morning in adults with multiple sclerosis (MS). METHODS: Fourteen adults with relapsing-remitting MS (RR-MS) (28.36 ± 6.81 years) were evaluated before and after nocturnal ingestion of MEL (6 mg) or placebo (PLA). Evaluations included a posturographic test of static bipedal postural balance with dual-task in eyes open (EO) and eyes closed conditions, and a clinical test of unipedal balance. The physical performance tests were: Timed Up and Go test (TUGT) (mobility), Four Square Step Test (FSST) (fall risk), and Timed 25-foot walk test (T25FWT) (walking speed). Cognitive performance [Montreal Cognitive Assessment (MoCA) and Simple Reaction Time (SRT) tests] and sleep quality [Spiegel's sleep questionnaire (SSQ)] were also assessed. RESULTS: In EO condition, MEL decreased the posturographic parameters [center of pressure (CoP) sway area (CoPAr), CoP path length (CoPL) and CoPL in the mediolateral axis (CoPLX)] more than PLA by 15.82% (p = 0.0006), 12.48% (p = 0.0004) and 14.25% (p = 0.0002), respectively. Durations of TUGT and FSST decreased following MEL session more than the PLA one by 14.52% (p = 0.017) and 19.85% (p = 0.0006), respectively. MEL increased the unipedal stance time, SSQ and MoCA scores more than PLA by 49.81% (p = 0.04), 32.21% (p = 0.004) and 11.87% (p = 0.008), respectively. CONCLUSION: This pilot study showed that acute nocturnal MEL ingestion seems to be safe for enhancing postural balance, fun mobility and fall risk in RR-MS adults probably through improving sleep quality and cognitive function.

Effects of Melatonin Ingestion Before Nocturnal Sleep on Postural Balance and Subjective Sleep Quality in Older Adults.

The present study aimed to investigate the effect of acute nocturnal melatonin (MEL) ingestion on sleep quality, cognitive performance, and postural balance in older adults. A total of 12 older men (58 ± 5.74 years) volunteered to participate in this study. The experimental protocol consisted in two testing sessions after nocturnal MEL (10 mg) or placebo ingestion the night before the tests. During each session, sleep quality tests, cognitive tests, and postural balance protocol were conducted. Static and dynamic postural control was assessed using a force platform. Most of the sleep parameters have been improved following nocturnal MEL ingestion without any effect on cognitive performance. Likewise, measurements related to the center of pressure (CoP) have been significantly decreased with MEL compared with placebo. In conclusion, postural control has been improved the morning following nocturnal MEL ingestion in older adults. This trend could be explained by the potential effect of MEL on sleep quality and cerebellum.

Comparison of recovery strategies on maximal force-generating capacity and electromyographic activity level of the knee extensor muscles.

CONTEXT: With regard to intermittent training exercise, the effects of the mode of recovery on subsequent performance are equivocal. OBJECTIVE: To compare the effects of 3 types of recovery intervention on peak torque (PT) and electromyographic (EMG) activity of the knee extensor muscles after fatiguing isokinetic intermittent concentric exercise. DESIGN: Crossover study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Eight elite judo players (age = 18.4 ± 1.4 years, height = 180 ± 3 cm, mass = 77.0 ± 4.2 kg). INTERVENTION(S): Participants completed 3 randomized sessions within 7 days. Each session consisted of 5 sets of 10 concentric knee extensions at 80% PT at 120°/s, with 3 minutes of recovery between sets. Recovery interventions were passive, active, and electromyostimulation. The PT and maximal EMG activity were recorded simultaneously while participants performed isokinetic dynamometer trials before and 3 minutes after the resistance exercise. MAIN OUTCOME MEASURE(S): The PT and maximal EMG activity from the knee extensors were quantified at isokinetic velocities of 60°/s, 120°/s, and 180°/s, with 5 repetitions at each velocity. RESULTS: The reduction in PT observed after electromyostimulation was less than that seen after passive (P < .001) or active recovery (P < .001). The reduction in PT was less after passive recovery than after active recovery (P < .001). The maximal EMG activity level observed after electromyostimulation was higher than that seen after active recovery (P < .05). CONCLUSIONS: Electromyostimulation was an effective recovery tool in decreasing neuromuscular fatigue after high-intensity, intermittent isokinetic concentric exercise for the knee extensor muscles. Also, active recovery induced the greatest amount of neuromuscular fatigue.

Evaluation of the posture and muscular strength of the trunk and inferior members of patients with chronic lumbar pain.

OBJECTIVE: We examine the postural profile and muscular forces of the trunk and inferior members of patients with chronic low back pain. METHODS: In this study, we include 60 subjects forming two groups: a first group (G1) of 30 patients with chronic low back pain and a second group (G2) of 30 healthy subjects. Every subject profited from an isokinetic evaluation of the muscular forces of the trunk (at 60 and 90°.s(-1)) and knees (at 60 and 120°.s(-1)) and of a postural evaluation. The isokinetic evaluation was carried out using Cybex(®) Norm II dynamometer with its Trunk Extension/Flexion (TEF) module set in concentric mode. The parameter under study was the torque peak. The postural evaluation was accomplished using the platform SATEL for the balance analysis associated with four conditions: static on stable plan open eyes (OE) then closed eyes (CE) and static on unstable plan OE then CE. The parameters under study were the averages of the total lengths, total surfaces, and the X and Y means. RESULTS: The averages of the torque peaks of the trunk flexor and extensor muscles at the speeds of 60 and 90°.s(-1) were inferior in group G1 as compared to G2. The differences were statistically insignificant only for the extensor muscles (p<0.005). The averages of the torque peaks of the knee flexors and extensors at 60 and 120°.s(-1) were the lowest in group G1. The differences were significant (p<0.05). The averages of postural parameters were more important in group G1, indicating a postural deficit in this group. CONCLUSION: We showed deficits of the posture and muscles of the trunk and knees of patients with chronic lumbar pain. The muscular deficit of the trunk predominates on extensors.