Rapid transmeridian translocation through multiple time zones has a negative impact on athletic performance. The aim of the present study was to test the timely use of three factors (melatonin treatment, exposure to light, physical exercise) to hasten the resynchronization of a group of elite sports competitors and their coaches to a westerly transmeridian flight comprising of 12 time-zones. Twenty-two male subjects were included in the study. They were professional soccer players and their coaches who travelled to Tokyo to play the final game of the Intercontinental Coup. The day prior to departure, urine was collected from each subject from 18:00 to 06:00 hrs to measure the melatonin metabolite 6-sulphatoxymelatonin. Participants were asked to complete sleep log diaries from day 0 (preflight) to the day before returning to Buenos Aires (day 8). All subjects received 3 mg of melatonin p.o. daily at expected bedtime at Tokyo immediately after leaving Buenos Aires. Upon arrival at Tokyo the subjects performed a daily physical exercise routine outdoors at two restricted times of the day (from 08:00 to 11:00 hrs in the morning and from 13:00 to 16:00 hrs in the afternoon). Exposure to sunlight or physical exercise at other times of the day was avoided. Except for the number of awakenings (which increased on days 1 and 3) and sleep latency (which decreased on days 2, 6 and 8), there was an absence of significant changes in subjective sleep parameters as compared with preflight assessment. Sleep quality and morning alertness at Tokyo correlated significantly with preflight 6-sulphatoxymelatonin excretion. Mean resynchronization rate of sleep-wake cycle to the 12 hr-time shift was 2.13 +/- 0.88 days, significantly different from the minimal resynchronization rate of 6 days expected after a 12-time-zones flight. The results indicate that the combination of melatonin treatment, an appropriate environmental light schedule and timely applied physical exercise can be useful to help elite athletes to overcome the consequences of jet lag.

BackgroundSports injuries produce changes in movement characteristics, which can be measured qualitatively and quantitatively in the ground reaction force.ObjectiveTo characterize the strength curve of a counter movement jump (CMJ) in professional footballers who were suffering from sports injuries.DesignCase-control study.SettingProfessional footballers of Club Atlético Boca Juniors.Participants32 players suffering from sports-related ankle, knee and muscle injuries, who were tested during the first week that they were able to jump, and 52 as control group, who were tested during preventive medical controls.Main Outcome MeasurementsWe analysed 5 stages of the force curve during CMJ: 1. Starting movement, 2. Start of eccentric contraction, 3. Eccentric contraction, 4. Peak eccentric, 5. Peak concentric, and rate of force development (RFD). In areas 1, 2 and 3 asymmetry was examined qualitatively (curve shape ), in zones 4 and 5, quantitatively (>5%).ResultsAll of injured players showed asymmetry versus 48% in control group (p<0.05), 85% of injured players showed deficits in zone 4 (16.5% in peak force vs 11,6% in control; p<0.05). Asymmetry of RFD in players with ankle and knee injuries was 26% and 14%, respectively, while those with psoas injuries presented inverted asymmetry(less force in non injury leg). Players with ankle injuries showed asymmetry in zones 1–4 and knee injuries in zones 1–5 (73% and 85% of the cases, respectively). Players treated surgically for knee injuries (ACL and menisci) demonstrated asymmetry in zones 4 and 5 in 100% of the cases. Players with adductor and hamstring injuries displayed asymmetry in zones 4 and 2–3, respectively (100% of cases for both). All players were symmetrical at return to sports.ConclusionsThe force plate is a device that allows the characterization of function in sports injuries during the rehabilitation process, and help establish parameters for the return of the athlete to a normal athletic life.

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