Sports medicine international open最新文献

Reply to the Letter to the Editor concerning "Cross-Cultural Adaptation and Validation of the Arabic Version of the Intermittent and Constant Osteoarthritis Pain Questionnaire" Sports Med Int Open 2020; 4(01): E8-E12; DOI: 10.1055/a-1031-0947.

The aim of study was to assess infants' behaviour during routine swimming sessions using a naturalistic observation method. The study sample included 14 infants (13.7±7.5 months old) with previous aquatic experience. The frequency of occurrences per unit of time (session) in the different dimensions - infant's motor behaviour and social-affective interaction - was registered over the course of two sessions by two independent experts. The behaviours most frequently observed were accompanied displacement (61.1%) and interaction with others (41.6%). Submersions or jumps represented only 8.4% of the session. Implementing a child-centred methodology leads to positive behaviours during this type of sessions, contributing to the child's healthy development.

The purpose of the study was to compare kinematics and muscle activity between two variations of unilateral squats under different stability conditions. Twelve male volunteers (age: 23±5 years, mass: 80±17 kg, height: 1.81±0.11 m, strength-training experience: 4.3±1.9 years) performed four repetitions with the same external load (≈4RM). Two variations (with the non-stance leg forwards vs. backwards) were performed in a Smith-machine and free-weight condition. The variables were barbell velocity, lifting time and surface electromyography activity of the lower extremity and trunk muscles during the descending and ascending phase. The main findings were 1) peak force was higher when performing the unilateral squats in the Smith machine; 2) peak ascending barbell velocity increased from repetition 3-4 with free weight; and 3) muscle activity from the rectus femoris, vastus lateral, biceps femoris, gluteus medius, and erector spinae increased with repetitions, whereas gluteus, and medial vastus and shank muscles were affected by the conditions. It was concluded that more peak force could be produced because of increased stability. However, peak barbell velocity increased from repetition to repetition in free-weight unilateral squats, which was probably because the participants grew more comfortable. Furthermore, increased instability causes more gluteus and vastus medial activation and foot variations mainly affected the calf muscles.

The study aimed to investigate the effects of ice slurry ingestion during break times and half-time (HT) on repeated-sprint performance and core temperature in the heat. Seven males performed two different trials as follows: ice slurry (-1°C) or room temperature water ingestion at each break and HT break at 36.5°C, 50% relative humidity. Participants performed 30 sets of 1-min periods of repeated- sprint exercises protocol using a cycling ergometer. Each period consisted of 5 sec of maximal pedaling, 25 sec of pedaling with no workload, and 30 sec of rest; two sets of exercise periods were separated by 10 min of rest. Each break was implemented for 1 min after every 5 sets. The rectal temperature in ice slurry ingestion was significantly lower than that of the room temperature water at 45 set (p=0.04). Total and mean work done was greater in ice slurry ingestion compared to room temperature water ingestion (p < 0.05). These results suggested that ice slurry ingestion during break times and HT break may be an effective cooling strategy to attenuate the rise of core temperature in the second half of exercise and improve the repeated-sprint exercise capacity in the heat.

The aim of this study was to investigate the effect of six-weeks of resistance training with different volume load on the maximum glycolysis rate. 24 male strength-trained volunteers were assigned in a high volume low load (50% of their 1RM with 5 sets and reps up to muscle failure) and a low volume high load (70% of their 1RM with 5 sets of ten reps) resistance exercise group. The resistance training performed 3 days per week over 6 weeks. The maximum glycolysis rate was determined using isokinetic force testing before and after the intervention. There was a significant increase in glycolysis rate over the training period across all subjects (p=0.032). High volume low load exercise increased significantly from 0.271±0.067 mmol·l ^-1 ·s ^-1 to 0.298±0.067 mmol·l ^-1 ·s ^-1 (p=0.022) and low volume high load exercise showed no significant changes from 0.249±0.122 mmol·l ^-1 ·s ^-1 to 0.291±0.089 mmol·l ^-1 ·s ^-1 (p=0.233). No significant effect on glycolysis rate was observed between the training groups (p=0.650). Resistance training increases glycolysis rate regardless of volume load.

The purpose of this study was to evaluate the relationship between: 1) laboratory-determined cycling peak oxygen consumption (VO _2max ) and AS performance in a new underwater swim test (UWST), and 2) cycling VO _2max and ventilatory threshold (VT) in cycling and performance score during a simulated AS solo routine. Trained artistic swimmers (n=15, 15.8±0.8 yrs., height: 169.1±5.4 cm, body mass: 57.1±6.3 kg) completed (1) a maximal incremental cycle test to exhaustion to determine VO _2max , (2) the UWST which comprised 275 m of freestyle and underwater breaststroke, and (3) a simulated solo competition where artistic swimming elements were evaluated by five FINA judges. There was a significant correlation between mean element score and (i) VO _2max (48±4 mL ^. kg ^. min ^-1 , r=0.44, p =0.05), and (ii) UWST (r=-0.64, p =0.005). However, there was an insignificant relationship between cycling ventilatory threshold and mean element score (r=-0.36, p =0.10). In addition, the results demonstrate a significant relationship between HR at the ventilatory threshold and peak HR of the UWST (r=-0.64, p =0.014). The results of this study demonstrate that VO _2max is an important determinant of AS performance. In addition, the UWST appears to be a useful indicator of AS performance.

The aim of this study was to examine the effects of overspeed or overload plyometric training on jump height and lifting velocity in resistance trained females without plyometric training experience. Fifty-six participants (age: 21.2±1.7 years; body mass: 65.1±8.2 kg; height: 168.0±5.9 cm) were randomly allocated to either an overspeed (n=18), overload (n=18), or passive control (n=16) group. The two training groups completed 18.7±1.7 sessions consisting of three different plyometric exercises with overspeed or overload over eight weeks. Apart from the external loading, the two training modalities were identical. Following the training period, the changes in the recorded variables were not significantly different from those in the control group, nor did the training groups differ from each other. The training groups improved peak and average lifting velocity in the 40 and 60% of body mass loading conditions (9.50-33.37%, p=<0.001-0.038), whereas only the average lifting velocity improved in the 80% of body mass loading condition (OS: 14.47%, p<0.001 and OL: 23.13%, p<0.001). No significant changes occurred in the control group (9.18-13.55%, P=0.062-0.980). Overspeed and overload plyometric training may be viable methods for improving lifting velocity, but not squat jump height, in a population without plyometric training experience.

Mountain bike cross-country Olympic has an intermittent performance profile, underlining the importance of short-term but high cycling power output. Previous findings indicate that power output during sprint tests differs between laboratory and field-based conditions and that cycling cadence rises with increasing workload. The aim was therefore to examine power output and cadence in short-term efforts under laboratory and field conditions. Twenty-three competitive athletes (17.9±3.7 years) performed a laboratory power profile test and a simulated race within one week. Power output and cadence during the power profile test were compared to corresponding short-term efforts during the race over durations of 10-300s (TT _10-300 ). Differences were TT ₁₀ +8%, TT ₃₀ +7%, TT ₆₀ -15% and TT ₃₀₀ -12% for power output and+10%,+8%,+19%,+21% for cadence respectively. Compared to the race, we found higher power output during the power profile test for the shorter efforts but lower for TT ₆₀ and TT ₃₀₀ . Confirming previous results, cadence was higher during the power profile test compared to the respective intervals of the race and increased with increasing workload or shorter time trial duration. Future research should take into account that compared to the field, a higher cadence is used in laboratory settings to produce similar power output.

Ischemic heart disease presents with significant differences between sexes. Endurance exercise protects the heart against ischemic disease and also distinctly impacts male and female patients through unidentified mechanisms, though some evidence implicates 5'-AMP-activated protein kinase (AMPK). The purpose of this investigation was to assess the impact of training and sex on cardiac AMPK activation following exhaustive exercise. AMPK activation was measured in trained and sedentary mice of both sexes. Trained mice ran on a treadmill at progressively increasing speeds and duration for 12 weeks. Trained and sedentary mice of both sexes were euthanized immediately following exhaustive exercise and compared to sedentary controls. Endurance training elicited adaptations indicative of aerobic adaptation including higher max running velocities and cardiac hypertrophy with no differences between males and females. AMPK activity was higher in male compared to females, and trained exhibited higher AMPK activity compared to sedentary mice. In response to training, male mice activated AMPK more robustly than female mice. Chronic exercise training increases the ability to activate cardiac AMPK in response to exhaustive exercise in a sex-specific manner. Understanding the interaction between exercise and sex is vital for use of exercise as medicine for heart disease in both men and women.