Journal of Sports Medicine and Physical Fitness最新文献

Background: During the basketball season, it is essential to carefully plan training and recovery activities to optimize players' performance. This study monitored training load and perceived recovery indicators in professional female basketball players across the preseason and in-season phases.

Methods: Seventeen professional female basketball players (age: 19.6±3.1 years; height: 180.2±5.9 cm; playing position: 8 backcourt, 9 frontcourt) were monitored for eleven consecutive weeks. Each morning, players reported their perceived recovery using a 10-point Total Quality of Recovery (TQR) Scale. After each training session or game, players reported their perceived exertion using the CR-10 Scale, which was multiplied by the duration of the training or game to obtain the session load. Weekly load, monotony, strain, TQRAM (morning recovery) and TQRfw (recovery at the start of the following week) were calculated. Linear mixed models were performed to assess the effects of season phase (preseason; in-season), playing position (backcourt; frontcourt) and group (senior; under) on load and recovery variables.

Results: Weekly load, monotony and strain were higher in the preseason than the in-season phase (all P<0.001, ES: moderate-large). Strain was higher in senior players compared to under (P=0.045, ES: small). Regarding recovery variables, no effects were found for TQRAM, while TQRfw was higher in the preseason than in-season (P<0.001, ES: moderate) phase.

Conclusions: Professional female basketball players experience lower internal loads but poorer perceived recovery during the in-season phase. Practitioners should carefully consider the stress of competition and the cumulative fatigue from high preseason loads during the transition from the preseason to the regular season.

Background: Foot and toe function is important for not only sports performance but also preventing and treating musculoskeletal disorders. Although strengthening training specific to intrinsic and extrinsic muscles has been recommended, insufficient information is available in toe exercises in their variation and evidences compared to shoulder or lumbopelvic training strategies. The aim was to examine the effects of a newly developed foot muscle exercise program on toe function in individuals during the growth period. This is a single-group, pretest-posttest case series.

Methods: Both feet of seven male patients in their growth period with sports-related overuse injuries of the lower extremities (mean age, 11 years) underwent a four-week strength exercise of the toes, consisting of intrinsic and extrinsic muscle-targeted exercises. Main outcome measures were as follows: 1) flexion force of each toe; 2) compression force of each toe; 3) dexterity of the toes evaluated using the "rock-paper-scissors test"; 4) toe loading during single-leg squat exercise. An F-scan system was used to measure 2 and 4.

Results: All patients performed the program appropriately and completed the program for four weeks. Significant improvements were observed in the outcome measures of 1 to 4.

Conclusions: The combined exercise program for the intrinsic and extrinsic muscles of the foot effectively improved toe strength, dexterity, and loading during dynamic motion and could be easily performed in individuals during the growth period.

Background: The purpose of this study was to investigate the effects of caffeinated chewing gum on female softball pitching and hitting performance in trained female softball fielders and pitchers.

Methods: Twenty-four trained female softball players (10 pitchers and 14 fielders) were divided into a caffeine chewing gum trial (CAF) or a placebo trial (PLA) in a single-blind, randomized, crossover experimental design. Two pieces of gum containing 100 mg of caffeine (CAF) or without caffeine (PLA) were chewed for 10 minutes and then spit out, followed by a 15-minute warm-up. The physical tests included grip strength and countermovement jump (CMJ). The softball-specific tests included pitching or hitting. The two trials were separated by seven days.

Results: The CAF trial had significantly higher grip strength than the PAL trial in fielder (P=0.032, Cohen's d=0.29) and pitcher (P=0.016, Cohen's d=0.33). The height of CMJ in fielders was significantly higher in the CAF trial than in the PLA trial (P=0.015, Cohen's d=0.65) but not in pitchers (P=0.596, Cohen's d=0.15). The fielder's average and maximum batting exit speeds were significantly higher in the CAF trial than in the PLA trial (P<0.05). The average and max fastball speeds of the CAF trial were significantly higher than that of the PLA trial in pitchers (P<0.05).

Conclusions: The study showed that chewing gum containing two pieces of gum containing 100 mg of caffeine effectively improved female softball fielder's batting performance and pitcher's pitching performance.

Background: This study examined the effects of caffeine (CAF) supplementation on game-related statistics and perceptual responses of male basketball players during official games.

Methods: Eight players (23.5±5.7 years) participated in this double-blind, placebo-controlled, randomized crossover study. Sixty minutes before the start of each game, players ingested a dose of either CAF (3 mg/kg body mass) or placebo (PLA) in a randomized order. Game-related statistics were collected. After the games, players reported ratings of perceived exertion (RPE) and their perceptions of endurance and power. Separate linear mixed models evaluated the effects of treatment (CAF, PLA), game location (home, away), and opponent level (better, worse) on game-related statistics and perceptual responses.

Results: Players committed fewer fouls when taking CAF compared to PLA (P<0.001, ES=0.75, moderate). No effects of CAF were found for the other game-related statistics (all P>0.05). RPE was higher in CAF compared to PLA (P=0.031, ES: 0.49, small). There were no differences in perceptions of endurance (P=0.388) or power (P=0.988). No effects of game location or opponent level were found for game-related statistics or perceptual responses (all P>0.05).

Conclusions: This study suggests that caffeine supplementation can improve defensive performance in semiprofessional basketball players while also possibly increasing physical performances, seen the higher RPE.

Background: Soccer involves many physically challenging actions and engaging in such activities can induce a decline in performance due to physical fatigue which predisposes players to develop injuries. The present study aimed to examine the impact of post-match fatigue on functional performance and Inter-Limb Asymmetry Index (LSI) in adolescent soccer players.

Methods: Thirty-eight adolescent male soccer players (15-18 years) completed a battery of functional performance measures (Rate of Perceived Exertion (RPE) scale, 10 m sprint, agility T-test, and Single leg hop for distance (SLHD) test). The data collection started prior to a soccer match and consisted of two testing sessions; two hours before the match, while the subsequent testing session was performed within two hours immediately following the match.

Results: The study results revealed a significant effect of post-match fatigue on change of direction abilities and SLHD (moderate effect size). However, no significant differences were observed in the 10 m sprint test and LSI (P>0.05).

Conclusions: Functional performance measures such as agility test and SLHD test can detect physical ability changes due to post-match fatigue in adolescent soccer players. The study findings offer insightful and practical information on the importance of employing field-based functional performance measures in monitoring players' recovery following a game.

Background: Blood flow restriction (BFR) has been shown to enhance the effectiveness of low load resistance exercise, but less research has examined its utility in conjunction with maximal isokinetic contractions, which may depend on the restrictive pressure and speed of contraction.

Methods: Individuals reported to the laboratory for three visits to complete three sets of 20 maximal elbow flexion exercises at 60°/s and 300°/s under 0%, 40% and 80% of their arterial occlusion pressure. Muscle thickness was measured before and after exercise, and ratings of discomfort, perceived activation, and exercise-induced feelings were obtained at the completion of each exercise. Fatigue was assessed as the decline in average peak torque across the three sets.

Results: A total of 27 individuals (11 females, 16 males) completed the study. There was a significant interaction for torque at both 60°/s and 300°/s (P<0.001), with each increasing pressure resulting in greater fatigue. Muscle swelling was present across all conditions but was lowest in the 40% BFR condition applied during the 300°/s speed. At both 60°/s and 300°/s speeds, the 80% BFR pressure was associated with lower enjoyment, greater discomfort, and greater perceived activation (all P<0.05).

Conclusions: The combined effects of BFR to maximal isokinetic contractions increased fatigue with less of an impact on muscle swelling. These results indicate that BFR may enhance the effectiveness of long-term isokinetic training, but it is also important to consider the addition of BFR was associated with lower levels of enjoyment and greater discomfort which may decrease adherence.

Background: Equestrians (horse riders) are more susceptible to low back pain than the general population due to loads placed on their bodies during the activity. A specific eight-week exercise intervention program targeting the muscles used during horse riding was implemented for a group of equestrians with low back pain.

Methods: Volunteers were invited to participate in the study through social media posts in Melbourne, Australia. The participants were required to complete an exercise screening test prior to enrolment in the study to ensure they were suitable to participate in the iteration program. Participants then completed the Brief Pain Inventory (BPI) (Short Form) and Patient Specific Functional Scale (PSFS) before commencing the exercise program. These outcome measures were completed again by participants after completing the 8-week exercise program.

Results: Nine equestrians (23-65 years of age; mean=43±14: average worst back pain on riding=7/10 with a range of 3-10/10) completed all outcome measures and the 8-week exercise intervention. Data indicate that all achieved improved pain severity, pain interference and riding functionality (P<0.01).

Conclusions: An eight-week exercise program may be beneficial in improving a sample of equestrians' chronic LBP symptoms. From a practitioner's perspective, the findings provide an indication as to suitable exercises to prescribe to an equestrian to help reduce their LBP.

Background: Ischemic preconditioning (IPC) has been suggested to improve exercise performance by 1-8%. Prior research concerning its impact on short-duration exercises, such as sprints, has been limited and yielded conflicting results. The aim of this study, which included a non-occlusion-based placebo control, was to determine whether IPC improves repeated sprint performance in a manner that accounted for psychophysiological effects.

Methods: Twenty-two healthy males participated in this study, which employed a randomized crossover design. Following the 10-min baseline period, participants received intervention under four different conditions: 1) no-intervention control (CON); 2) non-occlusion-based placebo control (SHAM); 3) remote IPC (RIPC); and 4) local IPC (LIPC). Participants then performed a standardized repeated sprint cycling (5×10s maximal cycling sprint, separated by a 40-s rest in each set).

Results: Repeated sprint performance, as indexed by average power output, peak power output, and total work, the improvement was observed in the RIPC and LIPC during the initial phase (set 1-3) when compared with CON (P<0.05). SHAM condition also showed an increase in peak power output in the set 1 (CON 9.97±1.05 vs. SHAM 10.30±1.13 w/kg, P<0.05), which may represent a psychophysiological component in the IPC-induced improvement. Higher lactate concertation was found in the SHAM and LIPC groups, than in the CON group, 5 minutes after the exercise (CON 15.72±0.68 vs. SHAM 16.82±0.41 vs. LIPC 17.19±0.39 mmol/L, P<0.0001 for both, respectively).

Conclusions: In conclusion, LIPC enhanced repeated sprint cycling performance during the initial phase, beyond what could be accounted for entirely by a psychophysiological effect. The improvement associated with RIPC, however, did not surpass the effect of a placebo intervention.

Background: Exercise training may reduce whole-body fat mass and percentage. However, whether exercise improves fat distribution assessed by fat mass ratio (FMR) and regional fat percentage in men living with HIV (MLHIV) is still unclear. The aim of this study was to compare the FMR and total and regional body fat between physically active and inactive MLHIV and HIV-uninfected men.

Methods: Using a cross‑sectional design, total and regional body fat assessed by dual x-ray absorptiometry (DXA) were compared between 19 MLHIV (ACT-MLHIV, 52±7 y, 23.8±4.1 kg.m^-2) enrolled in a multimodal training program (aerobic, strength and flexibility exercises) for at least 12 months (60‑min sessions; 3 times/wk with moderate intensity) vs. 19 inactive MLHIV (IN-MLHIV, 51±7 y, 25.9±3.3 kg.m^-2) and 19 HIV-uninfected men (HIV-, 51±8 y, 26.0±3.3 kg.m^-2). FMR was calculated as the ratio between the percentage of fat in the trunk and the lower limbs.

Results: The ACT-MLHIV showed a lower trunk fat percentage (24.1±17.9% vs. 34.4±11.9%; P=0.02) and FMR (1.5±0.6 vs.1.9±0.5; P=0.02) than the IN-MLHIV, with no difference between them in lower limbs fat percentage (IN-MLHIV: 16.3±5.9 vs. ACT-MLHIV: 15.9±9.6%; P=0.98). HIV- showed a lower FMR (1.2±0.2; P<0.02) and superior lower limb fat percentage (24.1±8.0%; P<0.0001) than IN-MLHIV and ACT-MLHIV, as well as a higher total fat percentage than ACT-MLHIV (27.3±6.2 vs. 21.8±6.9%; P=0.02).

Conclusions: Physical exercise seems to attenuate HIV-associated lipodystrophy by reducing trunk fat percentage while preserving lower limb fat mass. FMR and total fat percentage should not be used alone as markers of exercise-induced changes in lipodystrophy.