The effects of proprioceptive exercise training on physical fitness and performance of soccer skills in young soccer players.

The purpose of this study is to analyze the effect of proprioceptive exercise training on soccer skills and physical fitness in young soccer players. Nineteen young soccer players participated in the study. Participants were divided into proprioceptive exercises training (PT) and control (Cont) groups. The physical fitness and soccer skill performance test assessed at pre- and posttraining. Balance ability and power significantly improved in both groups after 8 weeks of training (P<0.05). Dribble in the PT group was similar between pre- and posttraining, with a statistically significant difference in the Cont group (P<0.05). There were no significant differences within and between groups according to training in the left and right feet for juggling. The PT and Cont groups did not differ significantly regarding short passes posttraining. However, a significant improvement in long passes was observed in the PT group after training period (P<0.05). Shooting was no different between and within the groups. In conclusion, these inconsistent findings are thought to be due to the applied exercise method, training duration, and the specificity of the physical growth period of the young players. Therefore, it is necessary to increase the frequency and time of proprioceptive exercise training and apply factors for cognitive ability improvement to training programs for young soccer players in future studies. These studies could suggest appropriate training methods necessary to improve the performance of young soccer players.

Impact of exercise training and diet therapy on the physical fitness, quality of life, and immune response of people living with HIV/AIDS: a randomized controlled trial.

BACKGROUND: Exercise and dietary nutrition are considered crucial in human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome (AIDS) treatment protocols and people living with HIV/AIDS (PLWHA) rehabilitation care. However, there is no well-studied research evaluating the effects of combined interventions on the fitness and immune systems of PLWHA. Therefore, this study aimed to analyze the effects of exercise and dietary intervention on physical fitness, quality of life and immune response in PLWHA. METHODS: This was an experimental study, with a sample of 25 male PLWHA divided into two groups: the intervention group (IG: 12 participants) and the control group (CG: 13 participants). All participants have not had any exercise habits and nutritional supplements in the past six months. The participants in the IG completed 45 min of exercise (60-80% HRmax) 4 times per week for 4 weeks. The exercise was in the form of brisk walking or running. They were also given a nutritional dietary supplement 3 times a day for 4 weeks. The 13 individuals in the CG continued their normal daily life (physical activity and diet). The following parameters were evaluated before and after the intervention: body composition, physical fitness, immune response, quality of life (QoL), stress, dietary behavior, dietary habits, exercise motivation, and physical self-efficacy. RESULTS: The significant changes were observed in burnout of stress variables and physical efficiency index (PEI) of physical fitness in the IG (p =.023). Moreover, in the saliva samples, sal-T levels significantly increased only after the intervention in the IG (p =.012). Additionally, regarding the analysis of the interaction (group × time), there was a significant improvement in the reaction speed (p =.001) and grip strength (left: p =.002, right: p =.030) and a significant difference in physical satisfaction in QoL (p =.001), stress burnout (p =.043), self-confidence in physical efficacy (p =.045), external display (p =.008), and fulfillment (p =.047) in exercise motivation. Moreover, the significant effect of the intervention on emotional eating in dietary behavior was shown in the comparison of the IG before and after intervention (p =.001) and in the comparison of the IG group with the CG after the experiment (p =.013). However, there was no significant effect of time or interaction between the condition and time on body composition. CONCLUSIONS: In conclusion, exercise training and diet therapy caused changes in physical fitness and Sal-T levels, which had positive effects on the health promotion of PLWHA.

Effects of cold water immersion and protein intake combined recovery after eccentric exercise on exercise performance in elite soccer players.

The purpose of this study is to analyze the effects of the combined recovery method of cold water immersion (CWI) and protein supplement intake after eccentric exercise that causes muscle fatigue in elite soccer players. Eleven semiprofessional soccer players participated in this study. Participants were divided into CWI group, combined protein and CWI group (PCWI), and passive resting group (CON). The participants completed the eccentric exercise for one hour and performed one of three recovery methods. The muscle strength of the quadriceps and hamstring muscles significantly decreased at 48-hr postexercise compared to before exercise in all recovery groups (P<0.05), with no significantly different between the recovery groups. The time required to sprint 40 m was significantly longer in all groups at 24 hr and 48 hr after exercise than before exercise (P<0.05). The vertical jump height was significantly decreased at 48 hr after exercise compared to before exercise in the CON and CWI groups (P<0.05). The muscle soreness values were higher at 6 hr, 24 hr, and 48 hr after exercise than before exercise in all groups (P<0.001). The perceived recovery quality was reduced after exercise in the PCWI (P<0.01) and CON groups (P<0.001) compared to before exercise; it was unchanged in the CWI group. The recovery quality decreased at 6 hr, 24 hr, and 48 hr after exercise in all recovery groups (P<0.01). In conclusion, the combined recovery method was less effective than CWI alone for the recovery of exercise performance.

Effects of physical activity level on quality of life, stress, and dietary behavior in people living with HIV/AIDS: A pilot study.

The aim of this study was to analyze the daily physical activity and the relationship between the physical activity levels and psychological variables of Koreans with HIV. Twenty-two people with HIV participated in this study. The participants completed questionnaires, and we assessed the daily physical activity for 2 weeks. The daily physical activity level of most of the participants was low-intensity; high-intensity activities were only performed for approximately 1 minute. The participants had unhealthy dietary habits, such as eating 2 meals a day, eating irregularly, and skipping breakfast. Psychological well-being and environmental satisfaction were higher in the high-intensity group than in the medium- and low-intensity groups (P < .05). The overall stress level among the groups was statistically significantly different (P < .05), and the stress level was lower in the high-intensity group than in the low- and medium-intensity groups. Restraint eating was higher in the low-intensity group than in the medium- and high-intensity groups (P < .05). However, among the groups, the external eating variable was highest in the high-intensity group (P < .05). Daily physical activity during positively affects the physical and mental well-being of people living with HIV.

Match activity profile of professional female soccer players during a season.

It is necessary to understand movement characteristics of elite female soccer players during a match to develop effective training program. The purpose of this study is to analyze the physical demands of Korean female professional soccer players during a competitive season. Twenty-four female professional players (age: 27.8±3.9 years; height: 165.7± 5.1 cm) from a team, belonging to the women's professional soccer league in South Korea participated in the study. The players participated in 11 home matches and 10 away matches from April 26 to November 9 of the 2011 season. Body weight and body mass index decreased during the first half-season compared to the preseason (P<0.05), and the decreased values were maintained until the second half-season. Total distance covered by the players was more than 9.5 km per match. No difference was found in the total distance, movement distance by exercise intensities, number of sprints and accelerations, and maximum speed between the first half- and second half-seasons. Midfielders covered the most distance during a match compared to other positions (P<0.05). Wing forward covered the most distance of high-intensity exercise. Maximum speed during the match was higher among wing forward and forward than in other positions (P<0.05). There were no significant differences between home and away matches in all variables (P>0.05). In conclusion, in order to improve the performance of female soccer players and prevent injuries, a training program should be constructed that considers the characteristics of each player and playing position rather than uniform training in a team.

The Effects of Exercise on Acute Immune Responses in Relative Leisure-Deprived People Living with HIV/AIDS: A Pilot Study.

Exercise training involving exercises of optimal intensity and duration improves psychological and medical variables in relative leisure-deprived people living with HIV/AIDS. This study aimed to analyze associated psychological variables and the effect of exercise intensity and duration on immune responses in relative leisure-deprived people infected with HIV. The participants completed different moderate-intensity exercises (30 min (60−80% HRmax) and 45 min (60−80% HRmax)) and high-intensity exercise for 10 min (>80% HRmax). Levels higher than "normal" were rated for relative leisure deprivation, indicating relative deprivation of leisure among participants. The overall level of quality of life was "normal", indicating that quality of life was not considered high. The stress level was psychologically considered low. Time had a significant effect on cortisol levels (p < 0.05). Compared to pre-exercise, cortisol level was significantly decreased immediately after moderate exercise for 45 min and 3 h post-exercise after high-intensity exercise for 10 min (p < 0.05). However, time and the interaction of condition and time had no significant effect on IL-6 and sIgA levels (p > 0.05). Despite the small sample size of this pilot study, the results demonstrate that moderate-intensity exercise can be recommended to improve the health and quality of life of people infected with HIV.

Epidemiology of soccer injuries in Korea women national team for 5 years.

The purpose of this study was to analyze the characteristics of injuries in female national soccer players. The injuries data were recorded by Korea Football Association medical staff using the Daily Medical Report provided by the Asian Football Confederation during a total 21 training camps and friendly and official matches from January 2014 to December 2018. A total of 483 players in the national team training camps and matches participated in the study, of which 377 players experienced more than one injury. Sports injuries accounted for 89% of the total 1,019 injuries; general diseases accounted for the remaining 11%. The number of injuries per 1,000 exposure hours was higher in matches than in training sessions. Most injuries that occurred during training and matches involved the lower extremities (79%). The most common injury diagnosed during training and matches was muscle rigidity (45%), followed by contusions/hematomas/bruises (22%) and sprain (15%). The largest proportions of injuries in terms of absence from soccer play were minimal injury (67%), followed by mild (29%), moderate (3.5%), and severe (1%). As conclusion, the characteristics of injuries during training sessions and matches were different. Rehabilitation and injury prevention programs need to developed for female soccer players to improve the players' performance.

Differences in physical fitness after an 8-week preseason training among elite football players aged 17-19 years.

There may be an optimal period of time to maximize the improvement of physical fitness during adolescence. The aim of this study was to examine the magnitude of changes in physical fitness after 8 weeks of preseason training according to chronological ages after the age at peak high velocity. Thirty male young football players from an elite football team (U-16, n=10; U-17, n=10; U-18, n=10) participated in the study. The players completed an 8-week general preseason football training and participated in the pre- and posttests to measure physical fitness. The 8-week preseason training improved the power of all young players (P<0.05). The 20-m sprint performance was improved by training in U-16 and U-18 (P<0.05), but no changes were found in the U-17 group (P>0.05). Significant differences were found in the arrowhead left in U-16 and U-18 (P<0.05) after training; however, no difference was observed in U-17 (P>0.05). Coordination was enhanced further in U-16 and U-17 (P<0.05) compared with that in U-18 (P>0.05). The performance of repeated sprints and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) were similar between pre- and posttraining in all age groups (P>0.05). Collectively, the results emphasized the importance of systematic and scientific training methods to improve the fitness levels of young football players in the preseason training period. Moreover, training to improve coordination in young football players is effective at younger ages.

The effects of residential environment on the condition and fitness of soccer players in the summer.

Exercise performance is reduced in hot environments due to physiological responses caused by increased body temperature. A proper residential environment is important for improving the performance and maintaining physical condition of soccer players in the summer. The purpose of this study was to determine the effect of indoor temperature of the resting space during the summer on the fitness and condition of soccer players. A total of 12 K-3 League semiprofessional players without serious injuries in the last 3 months voluntarily participated in the study. Participants performed speed (10 m, 20 m, and 30 m), soccer-specific coordination skill (dribbling), agility, repeated sprints, Yo-Yo intermittent level 2, vertical jump, and questionnaire (fatigue, sleep quality, muscle soreness, stress, and mood) after staying indoor temperature at 20°C, 26°C, and 30°C for one night, respectively. There was no difference among groups in physical fitness (speed, agility, jump, coordination, Yo-Yo intermittent level 2, and repeated sprints). The differences in fatigue and sleep quality were not statistically significant among groups, but they tended to be different. Muscle soreness was similar among all groups. Significant differences were observed between the 20°C and 30°C groups in stress and mood levels. The present study concluded that, while the physical fitness did not differ among groups, the 30°C residential environment was shown to have a negative psychological effect. Considering that many diseases associated with hot weather occur in low residential temperatures, a room temperature of 26°C is recommended for elite soccer players in hot summer weather.

Activity Profiles of Top-Class Players and Referees and Accuracy in Foul Decision-Making During Korean National League Soccer Games.

Joo, CH and Jee, H. Activity profiles of top-class players and referees and accuracy in foul decision-making during Korean national league soccer games. J Strength Cond Res 33(9): 2530-2540, 2019-The aims of this study were to compare the activity profiles between the top-class referees and players and elucidate the factors related to foul decision-making. Three hundred thirty-five elite-level players and referees were analyzed for distance covered during 20 matches of nationally held 2016 Korean league competitions. Distance covered by the players and referees was analyzed for the activity zones (slow walking, walking, jogging, running, high-intensity running, and sprinting) and 15-minute match periods. Mean distance between foul play and referee locations, foul plays, and 15-minute match periods were compared with the foul decision errors. Foul play and decision error rates (%) were also analyzed per segmented pitch zone. Although the total distance covered during a match and distances covered by jogging, running, and sprinting were significantly different between the players and referees, differences were within 1%. Significant differences in the distance covered before and after halftime were observed. The greatest distance between the foul play and referee locations, number of foul plays, and number of foul decision errors were observed at the 75-minute match period. Finally, the greater number of foul plays was observed in the neutral and attacking zones, and the foul decision errors were observed in the right defensive and left attacking zones 1. In conclusion, although the activity profiles may be different, referees should maintain certain level of physical fitness to match that of the players. To reduce the number of foul decision errors, factors such as match time, foul occurring location, and distance between foul play and referee locations should be considered.

Analysis of injury incidences in the Korea national men's soccer teams.

The purpose of this study was to identify the frequency and characteristics of injuries that occurred during the training camps and matches of the national soccer teams (under-20 [U-20], under-23 [U-23], A men's national teams). The research data were based on injuries that occurred from January 2016 to December 2017. The athletic trainer, a member of the Korea Football Association, recorded injuries based on the recording sheet of the Asian Football Confederation Daily Medical Report. A total of 1,689 (984 in 2014; 705 in 2017) injuries were reported for the 2 years. Most injuries were sports injuries (95%, sprains, etc.), and other conditions such as respiratory, digestive, and ocular, comprised only 5% of cases. The most injured areas of the national team players were the lower limbs (85%, 1,366). The frequency of the head/trunk and upper extremity injuries were relatively low (8.4%, 135; 6.5%, 105). The frequency of injuries according to positions were as follows: midfielder (40.3%, 648), defender (36.6%, 688), forward (17.8%, 286), and goalkeeper (5.2%, 84). The most common types of injuries were contusions (37.3%, 599), followed by muscle rigidity (29.0%, 466) and sprains (16.8%, 270). The characteristics of injuries amongst national soccer teams, according to age, were similar, but the injury characteristics for each position were different. Therefore, when organizing training programs for prevention and rehabilitation of athlete injuries and improvement of performance, it is necessary to consider the performance characteristics of each position.

The effects of short term detraining and retraining on physical fitness in elite soccer players.

PURPOSE: The aim of this study was to examine the effects of aerobic high-intensity training with reduced volume and training cessation on body composition and physical fitness after the end of season and the time required to recapture physical fitness with intensified retraining following two weeks of detraining in elite soccer players. METHOD: Twenty male semi-professional soccer players participated in this study. The soccer players were assigned to either a group that completed high-intensity aerobic training (HAT, n = 10) or to a detraining and retraining group (DHAT, n = 10) for a 5-week period immediately after the end of the season. The first 2 weeks of the period, members of the HAT group performed high-intensity aerobic exercise (80-90% of HRmax, 12 min × 3, three times per week), whereas members of the DHAT group abstained from any physical activity. During the subsequent 3 weeks, members of both the HAT and DHAT groups completed high-intensity aerobic exercise. Exercise performance testing and body composition analysis were performed before; after 2 weeks of detraining; and at 1, 2 and 3 weeks of retraining. RESULTS: Intensified high-intensity training for 5 weeks maintained the performance in the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) and repeated sprints at any time point (P > 0.05). However 2 weeks of detraining resulted in significant decreases in the performance on the Yo-Yo IR2 (P < 0.01) and repeated sprints test (P < 0.05). Performance on the Yo-Yo IR2 enhanced after 2 weeks of retraining and was maintained up to 3 weeks after retraining, with no significant differences between conditions (P > 0.05). In addition, repeated sprint performance markedly decreased after the detraining period (P < 0.05) and was continuously lower compared to the baseline at 2 weeks after retraining (P < 0.05). Furthermore, this value reached baseline level at the end of the experimental period (P > 0.05). There were no significant differences between conditions in body composition, performance of agility, or sprint ability throughout the 5-week experimental period (P > 0.05). CONCLUSIONS: The present data suggest that short-term detraining after the competitive season can markedly decrease performances in the Yo-Yo IR2 test and repeated sprints. To return to a previous level of ability on the Yo-Yo IR2 and/or sprint test with retraining through high-intensity aerobic training after a period of detraining, a similar or longer period of retraining is required. However, the high-intensity training with reduced amount of training after competitive season can prevent reductions in physical fitness.

Comparison of technical and physical activities between 8 vs. 8 and 11 vs. 11 games in young Korean soccer players.

The aims of this study were to examine the differences in technical aspects and physical demands between small-size games (SSG; 8 vs. 8) and regular-size games (RSG; 11 vs. 11) in young Korean soccer players. Seventy-nine young soccer players from 6 teams (U-12) volunteered to participate in the study. The players completed 4 games (2 SSG, 62×51 m, and 2 RSG, 80×54 m) in 2 days. Each game was filmed to evaluate technical actions. Physical demand variables were measured using global positioning system technology. SSG showed significantly greater numbers of technical plays among 17 variables when compared to RSG (P<0.05). The players covered significantly greater total distance during low-, moderate-, and high-speed running and sprinting in SSG than in RSG (P<0.05). Higher numbers of high-intensity activities (repeated high-intensity efforts, explosive efforts, decelera-tions, accelerations, and sprinting) were observed in SSG compared to RSG (P<0.05). Mean heart rate was also higher in SSG than in RSG (P<0.05). Despite the greater physical demands during SSG, the exercise intensity was similar to that reported in previous studies. Therefore, the SSG format applied in the present study can be a suitable official game format for Korean young soccer players, resulting in significantly greater exposure to technical plays without excessive physical demands.

The effects of short-term detraining on exercise performance in soccer players.

The aim of the present study was to determine whether 1 week of training cessation can affect exercise performance in well-trained soccer players. Upon the completion of a competitive season, 11 male soccer players went through 1-week training cessation. Performances in the 5-m (1.05±0.04 sec vs 1.02±0.03 sec, P=0.03) and 10-m (1.79±0.06 sec vs 1.74±0.06 sec, P=0.03) sprints were significantly increased after 1 week of detraining with a trend for an increase in the 20-m sprint performance (3.07±0.06 sec vs 3.02±0.07 sec, P=0.06). However, the repeated sprint performance (total sprint time [45.7±2.6 sec vs 48.0±2.6 sec, P=0.01] and fatigue index [5.8%±2.8% vs 7.8%±3.2%; P=0.04]) were reduced. In addition, no significant differences were observed for the 30 m (4.23±0.06 sec vs 4.24±0.09 sec, P=0.63), agility (right: 8.08±0.17 sec vs 8.03±0.37 sec, P=0.54; left: 8.05±0.21 sec vs 8.04±0.30 sec, P=0.84), coordination (13.98±1.21 sec vs 14.06±1.34 sec, P=0.75), Yo-Yo intermittent recovery level 2 (1,040.0±291.8 m vs 1,134.5±232.7 m, P=0.08), and knee extensors and flexors peak torques at all applied angular velocities (P<0.05) after detraining. These results indicate that short-term detraining for well-trained soccer players has a significant effect on the speed endurance performance. It is therefore important for the players and their coaches to plan a suitable training program to maintain exercise performance especially speed endurance during off-season.

Analysis of physical fitness and technical skills of youth soccer players according to playing position.

The purpose of this study was to compare performance factors of youth soccer players according to position. A total of 101 high school soccer players were selected and were classified into goalkeeper (n=7), defense (n=37), midfield (n=39), and forward (n=18) positions. All subjects were subjected to the Wingate test for anaerobic capacity, shuttle run test for aerobic capacity, and pass, kick, dribble, and shooting tests for soccer skills. There was no significant difference in aerobic capacity according to position. However, anaerobic capacity was significantly higher in defenders than midfielders (P<0.05), and soccer skills were significant lower in goalies than in other positions (P<0.01). The results show significant differences in anaerobic capacity and soccer skills according to position in youth soccer players. Therefore, we suggest that middle and high school soccer players should improve aerobic, an-aerobic capacity, and soccer skills irrespective position to achieve high-level soccer performance.

Development of a non-damaging high-intensity intermittent running protocol.

The aim of the present study was to devise a non-damaging high-intensity intermittent running protocol. Ten healthy active men completed high-intensity interval running (8× 3-min bouts at 90% of maximal oxygen uptake interspersed with 3-min recovery) on a motorized treadmill under normal laboratory temperatures. Mean heart rate and rating of perceived exertion significantly increased during the intermittent protocol (the first bout, 15.3± 1.2; the final bout, 18.6± 0.9; P< 0.001). Blood lactate concentrations were significantly elevated following bout 1 compared with resting values (1.2± 0.3 mmol/L vs 5.4± 2.4 mmol/L; P = 0.03). However, no significant reduction in maximal voluntary contraction was observed immediately after completing the last exercise bout (623.9± 143.6 N) or during the subsequent 7-d period compared to pre-exercise values (P = 0.59). Creatine kinase (CK) concentrations were not significantly increased following exercise or during the subsequent 7-d period (P = 0.96). Myoglobin (Mb) content was significantly increased following exercise (P = 0.01), however, values returned towards pre-exercise concentrations after 24 h. These results indicate that the high-intensity intermittent running protocol induced changes in physiological and subjective indices that are consistent with the effects of acute fatigue as opposed to those changes normally associated with exercise-induced muscle damage. This exercise protocol can therefore be used to investigate the influence of high-intensity exercise from physiological responses to molecular adaptation.

Acute simulated soccer-specific training increases PGC-1α mRNA expression in human skeletal muscle.

The aim of the current study was to quantify oxygen uptake, heart rate and molecular responses of human skeletal muscle associated with mitochondrial biogenesis following an acute bout of simulated soccer training. Muscle biopsies (vastus lateralis) were obtained from nine active men immediately pre-completion, post-completion and 3 h post-completion of a laboratory-based soccer-specific training simulation on a motorised treadmill. The soccer-specific simulation was a similar intensity (55 ± 6% [Formula: see text]) and duration (60 min) as that observed in professional soccer training (e.g. standing 41%, walking 37%, jogging 11%, high-speed running 9% and sprinting 2%). Post-exercise, muscle glycogen decreased (Pre; 397 ± 86 mmol∙kg(-1) dw, Post; 344 ± 64 mmol∙kg(-1) dw; P = 0.03), plasma lactate increased (P < 0.001) up to ~4-5 mmol∙L(-1), non-esterified fatty acids and glycerol increased (P < 0.001) to values of 0.6 ± 0.2 mmol∙L(-1) and 145 ± 54 µmol∙L(-1), respectively. PGC-1α mRNA increased (P = 0.009) fivefold 3 h post-exercise. We provide novel data by demonstrating that soccer-specific training is associated with increases in PGC-1α mRNA. These data may have implications for practitioners in better understanding the metabolic and muscle responses to soccer-specific training protocols in the field.

Influence of cold-water immersion on limb and cutaneous blood flow after exercise.

PURPOSE: This study aimed to determine the influence of cold (8°C) and cool (22°C) water immersion on femoral artery and cutaneous blood flow after exercise. METHODS: Twelve men completed a continuous cycle exercise protocol at 70% peak oxygen uptake until a core temperature of 38°C was attained. Subjects were then immersed semireclined into 8°C or 22°C water to the iliac crest for 10 min or rested. Rectal and thigh skin temperature, deep and superficial muscle temperature, thigh and calf skin blood flow (laser Doppler flowmetry), and superficial femoral artery blood flow (duplex ultrasound) were measured before and up to 30 min after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure). RESULTS: Reductions in rectal temperature were similar (0.6°C-0.7°C) in all three trials (P = 0.38). The mean ± SD thigh skin temperature during recovery was 25.4°C ± 3.8°C in the 8°C trial, which was lower than the 28.2°C ± 1.4°C and 33.78°C ± 1.0°C in the 22°C and control trials, respectively (P < 0.001). Recovery muscle temperature was also lowest in the 8°C trial (P < 0.01). Femoral artery conductance was similar after immersion in both cooling conditions and was lower (∼55%) compared with the control condition 30 min after immersion (P < 0.01). Similarly, there was greater thigh (P < 0.01) and calf (P < 0.05) cutaneous vasoconstriction during and after immersion in both cooling conditions relative to the control condition. CONCLUSION: Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation by virtue of greater reductions in muscle temperature and not muscle blood flow.

Postexercise cold-water immersion does not attenuate muscle glycogen resynthesis.

PURPOSE: The aim of this study was to test the hypothesis that postexercise cold-water immersion (CWI, via its associated reductions in skeletal muscle blood flow) attenuates muscle glycogen resynthesis during short-term recovery from exhaustive exercise. METHODS: In a repeated-measures design, nine recreationally active men performed an exhaustive glycogen depleting cycling protocol (consisting of intermittent exercise the night before and steady-state exercise on the subsequent morning of the main trial) followed by 10 min of lower-limb CWI (8°C) or remained seated in normal ambient conditions (CONT). Subjects were fed carbohydrate (CHO) at an ingestion rate of 0.6 g·kg body mass at 30 min postexercise and at 1, 2, and 3 h postexercise. RESULTS: Reductions in thigh skin temperature and muscle temperature during postexercise recovery were greater in CWI compared with CONT (P < 0.01). In addition, norepinephrine and blood glucose concentrations were increased and decreased, respectively, during recovery in CWI compared with CONT (P < 0.01). Postexercise muscle glycogen (CONT and CWI postexercise = 76 ± 43 and 77 ± 26 mmol·kg dry weight [dw], respectively; mean ± SD) progressively increased (P < 0.01) during recovery, although rates of resynthesis did not differ (P = 0.719) between conditions (CONT and CWI 4 h postexercise = 160 ± 34 and 157 ± 59 mmol·kg dw, respectively). Total glycogen synthesis during recovery was comparable (CONT and CWI = 83 ± 43 and 79 ± 58 mmol·kg dw, respectively). CONCLUSIONS: Postexercise CWI does not attenuate muscle glycogen resynthesis rates during short-term recovery even when CHO availability is considered suboptimal. Athletes who regularly incorporate CWI as a recovery strategy to alleviate symptoms of exercise-induced muscle damage should therefore not be concerned with potential negative effects of the associated reductions in muscle blood flow on the restoration of muscle glycogen stores.