ResearchPad - training-testing https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Adaption of Maximal Glycolysis Rate after Resistance Exercise with Different Volume Load]]> https://www.researchpad.co/article/N448586a4-2f80-4441-8bd7-5c0f774263c5 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.

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<![CDATA[Cycling Performance in Short-term Efforts: Laboratory and Field-Based Data in XCO Athletes]]> https://www.researchpad.co/article/N55e6ee6b-9641-4716-84c1-d7ea3ee84d88

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.

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<![CDATA[Effects of Overspeed or Overload Plyometric Training on Jump Height and Lifting Velocity]]> https://www.researchpad.co/article/Na13c781d-ac24-4178-806b-50b05e0b81d1

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.

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<![CDATA[ Relationship between VO 2max , under Water Swim Testing and Artistic Swim Solo Performance ]]> https://www.researchpad.co/article/N727636d3-3847-4542-ba94-a60abd81d3bf

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.

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<![CDATA[Establishing Reference Cardiorespiratory Fitness Parameters in Alzheimer’s Disease]]> https://www.researchpad.co/article/N7b1455d9-6d49-4be0-ad34-9e3780ba3645

Evidence is growing for aerobic exercise training as a viable means to attenuate cognitive losses associated with Alzheimer’s disease. The mechanism of action for aerobic exercise’s cognitive benefits is likely enhanced cardiorespiratory fitness and its response to incremental aerobic exercise have been incompletely evaluated in Alzheimer’s disease. The aim of this analysis was to establish cardiorespiratory fitness reference values in older adults with mild to moderate Alzheimer’s disease using a cardiopulmonary graded exercise testing. Ninety-seven community-dwelling older adults with mild to moderate Alzheimer’s disease underwent a symptom limited cardiopulmonary graded exercise test on a cycle ergometer. Differences between sexes and between Alzheimer’s disease participants with and without diagnosis of cardiovascular diseases were assessed by independent T-tests. Peak oxygen consumption was 10–20% lower than those achieved by similar clinical populations on treadmill tests. As expected, males produced significantly higher peak oxygen consumption compared to females (p =0 .02). However, the presence of concurrent cardiovascular disease did not result in statistically significant lower peak oxygen consumption compared to those without cardiovascular disease. These data provide a frame of reference for metabolic, cardiovascular, and ventilatory function during cardiopulmonary graded exercise testing performed on cycle ergometer in older adults with mild to moderate Alzheimer’s disease.

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<![CDATA[Prediction of Ergogenic Mouthguard Effects in Volleyball: A Pilot Trial]]> https://www.researchpad.co/article/N60e08b7c-1226-4549-ac93-e1479e2d4893

Dental occlusion may affect static and dynamic balance. The effects of a mouthguard on pinpoint accuracy in volleyball were investigated in 28 players who completed a volleyball specific test. Also, masticatory electromyographic tests were performed. The mean pinpoint accuracy was significantly higher with a mouthguard (68.6±9.3 vs. 64.0±7.0 points from 100; p< 0.006). However, differential mouthguard effects were seen, and three subgroups were classified: Group 1 (markedly improved pinpoint accuracy), Group 2 (improved pinpoint accuracy), and Group 3 (reduced pinpoint accuracy). Group 1 had a high masseter resting tone, the masseter activity was low in MVC (maximum voluntary clench) and increased in BOC (maximum bite on cotton rolls; p< 0.04). This indicates a masseter weakness, which would be compensated by a mouthguard. In Group 2, the masseter activity in MVC was high-normal with an imbalance which was improved in BOC (p< 0.01), indicating a possible mouthguard benefit. In Group 3, MVC and BOC were in a high-normal range and showed no relevant deficits. In these subjects the mouthguard had adverse effects. Overall, subjects with masticatory deficits had a benefit from the mouthguard in pinpoint accuracy. Positive or negative mouthguard responders may be detectible from electromyographic tests.

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<![CDATA[Validity and Reliability of the Apple Watch for Measuring Heart Rate During Exercise]]> https://www.researchpad.co/article/5c19afb4d5eed0c484c4751f

We examined the validity and reliability of the Apple Watch heart rate sensor during and in recovery from exercise. Twenty-one males completed treadmill exercise while wearing two Apple Watches (left and right wrists) and a Polar S810i monitor (criterion). Exercise involved 5-min bouts of walking, jogging, and running at speeds of 4 km.h −1 , 7 km.h −1 , and 10 km.h −1 , followed by 11 min of rest between bouts. At all exercise intensities the mean bias was trivial. There were very good correlations with the criterion during walking (L: r=0.97; R: r=0.97), but good (L: r=0.93; R: r=0.92) and poor/good (L: r=0.81; R: r=0.86) correlations during jogging and running. Standardised typical error of the estimate was small, moderate, and moderate to large. There were good correlations following walking, but poor correlations following jogging and running. The percentage of heart rates recorded reduced with increasing intensity but increased over time. Intra-device standardised typical errors decreased with intensity. Inter-device standardised typical errors were small to moderate with very good to nearly perfect intraclass correlations. The Apple Watch heart rate sensor has very good validity during walking but validity decreases with increasing intensity.

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<![CDATA[The within-participant Correlation between s-RPE and Heart Rate in Youth Sport]]> https://www.researchpad.co/article/5c19afb0d5eed0c484c4744d

The monitoring of training load is important to ensure athletes are adapting optimally to a training stimulus. Before quantification of training load can take place, coaches must be confident that the tools available are accurate. We aimed to quantify the within-participant correlation between the session rating of perceived exertion (s-RPE) and summated heart rate zone (sHRz) methods of monitoring internal training load. Training load (s-RPE and heart rate) data were collected for rugby, soccer and field hockey field-based training sessions over a 14-week in-season period. A total of 397 sessions were monitored (rugby n=170, soccer n=114 and field hockey n=113). Within-subject correlations between s-RPE and sHRz were quantified for each sport using a general linear model. Large correlations between s-RPE and the sHRz method were found for rugby (r=0.68; 95% CI 0.59–0.75) and field hockey (r=0.60; 95% CI 0.47–0.71) with a very large correlation found for soccer (r=0.72; 95% CI 0.62–0.80). No significant differences were found between the correlations for each sport. The very large and large correlations found between s-RPE and the sHRz methods support the use of s-RPE in quantifying internal training load in youth sport.

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<![CDATA[The Effect of Repetitive Rugby Scrummaging on Force Output and Muscle Activity]]> https://www.researchpad.co/article/5c19afa7d5eed0c484c47299

During rugby scrummaging, front row forwards encounter high levels of force that has been suggested to cause transient fatigue and is likely to reduce subsequent performance. However, little is known about the effect of repetitive scrummaging on force output and onset of fatigue. Twelve male front row forwards (21.5±2.3 yr; height 185.7±4.4 cm; body mass 108.5±7.1 kg) each performed three sets of five maximal-effort isometric scrums for 10 s, with 40 s rest separating each repetition; 2 min recovery was provided between each set. Force output and electromyography (EMG) of the right medial gastrocnemius (MG), biceps femoris (BF), gluteus maximus (GM), erector spinae (ES), rectus abdominis (RA), external oblique (EO), internal oblique (IO), and rectus femoris (RF) were assessed. There was no significant force decrement from performing 15 scrums and no fatigue was detected from EMG median frequency and mean amplitude. For training and practice purposes, coaches and trainers can be confident that 15 individual repetitive static scrums against a machine are unlikely to cause a reduction in force production and promote fatigue. However, the effect of rugby-related activities in conjunction with scrummaging requires further research to determine if transient fatigue is causal to scrummaging for subsequent performance.

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<![CDATA[Is Vigorous Exercise Training Superior to Moderate for CVD Risk after Menopause?]]> https://www.researchpad.co/article/5c19afa5d5eed0c484c4722c

Postmenopausal women have an increased risk for cardiovascular disease through many factors, such as a sedentary lifestyle and reduced heart rate variability (HRV). Endurance training improves coronary risk but the role of exercise intensity is unclear. The purpose of this observational study was to evaluate the effects of moderate versus vigorous exercise on cardiovascular disease risk in postmenopausal women. Thirty-six postmenopausal women who self-reported training at moderate (3–5.9 METS; n=18; age 58.9±4.4yr) or vigorous intensities (>6 METS; n=18; age 59.7±5.2yr) participated. C-reactive protein (CRP), HRV, VO 2 max, and stress (Perceived Stress Survey, Menopause Rating Scale) were measured. Groups were compared using independent samples t- tests, and associations of exercise intensities with CRP and HRV were assessed using multiple regression. CRP, HRV, and VO 2 max were similar ( p >0.05). Vigorous exercise had lower stress subscale scores ( p <0.01) and higher counter-stress subscale scores compared to moderate ( p <0.05). There was a positive association between time spent in vigorous exercise and HRV ( p <0.05).Vigorous exercise may not confer additional benefits in CRP and HRV over moderate, except for stress reduction. However, more time spent in vigorous exercise was associated with higher HRV. Therefore, increased parasympathetic tone may provide cardioprotection after menopause.

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<![CDATA[Intra- and Inter-Day Reliability of Body Composition Assessed by a Commercial Multifrequency Bioelectrical Impedance Meter]]> https://www.researchpad.co/article/5c19af98d5eed0c484c46f6e

The purpose of this study was to examine the intra- and inter-day reliability of body composition measurements provided by a commercial multifrequency bioelectrical impedance meter. Eighteen healthy, well-trained students in physical education from the same ethnic group were assessed on four consecutive days, both in the morning and in the evening. Indexes provided by the device were gathered in four categories: tissular, metabolic, hydric and ionic blocks. There was no systematic bias between repeated measures, regardless of time of day. Relative reliability was high to very high in the morning (0.72<ICC<0.99) and moderate to very high in the afternoon (0.61<ICC<0.99). Absolute reliability varied substantially between indexes (1.5%<SEM<15%). The minimum difference considered as real was proportionally altered, since it ranged from 4.2 to 41.5%. In conclusion, body composition assessed with a multifrequency bioelectrical impedance meter requires a highly standardized protocol and adjusting the cut-off value for each parameter to ascertain during athlete follow-up that a real change has occurred. This assessment should preferably be scheduled in the morning in order to decrease these cut-off values.

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<![CDATA[Ischemic Preconditioning and Acute Recovery of Performance in Rugby Union Players]]> https://www.researchpad.co/article/5c19afa9d5eed0c484c472f3

Ischemic preconditioning has been used as a training and/or pre-competition strategy; however its use for post-exercise recovery is still unclear. This study aimed to evaluate the impact of ischemic preconditioning on performance and recovery ratings following a simulated match in sub-elite rugby players. Following baseline measures, male players (n=8) performed a 40 min, rugby-specific exercise protocol followed by an intervention: 21 min of ischemic preconditioning (3×5 min occlusion at 220 mmHg with 2 min reperfusion at 0 mmHg) or passive rest (control) on 2 separate days. An agility T-test, a single vertical countermovement jump and 30 s of continuous vertical jumps were performed at baseline (–24 h), immediately after exercise, and immediately after the intervention. The rugby-specific exercise protocol induced similar mean heart rates (158.3±18.0 vs. 158.7±16.0 bpm) and perceived exertion levels (8.2±0.9 vs. 8.0±1.0) for both trials with all recovery performance measures and rating of recovery (13.9±1.4 vs. 13.6±1.6) similar between ischemic preconditioning and control trials (best p=0.385). We conclude that the use of ischemic preconditioning does not improve recovery acutely (~1 h) including specific variables related to rugby performance in amateur rugby union players.

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<![CDATA[Reliability and Accuracy of Ball Speed During Different Strokes in Young Tennis Players]]> https://www.researchpad.co/article/5c19b352d5eed0c484c53317

This study aimed to examine the relationship between anthropometric and sport level (SL) variables and both ball speed and accuracy in young male competitive tennis players. A secondary aim of this study was to analyze the possible differences in ball speed and accuracy between players of different competitive levels. A total of 85 players (age: 14.7±2.4 years; height: 1.65±0.12 m; body weight: 56.3±13.4 kg) were divided into five groups according to their positions in the ranking list. To measure stroke performances, the goal was to hit 20 balls at the maximum possible speed inside the court, with the opportunity of hitting a maximum of 30 balls for each groundstroke and 40 for serve. Accuracy was calculated by dividing the number of balls inside the default surface by the total number of hits. The ball speed showed high reliability for all three strokes assessed. The ball speed progressively increased as SL increased for all strokes, whereas accuracy remained unchanged across SL groups. All independent variables presented significant relationships (r=0.59–0.85, p<0.05–0.001) with ball speed for all strokes. However, after applying partial correlations these relationships decreased substantially (r=0.02–0.51). The accuracy showed significant relationships with SL only in the serve (r=0.31, p<0.05) and backhand (r=0.26, p<0.05) strokes. In conclusion, the results of the present study suggest that tennis performance depends on increasing ball speed while maintaining a relatively stable level of accuracy.

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<![CDATA[Predictive Factors for Vitamin D Concentrations in Swiss Athletes: A Cross-sectional Study]]> https://www.researchpad.co/article/5c19b356d5eed0c484c533e5

Vitamin D concentrations corresponding to 75 nmol/L 25(OH)D have been associated with maintained muscle function, growth and regeneration, optimal bone health and immunology in athletes. The objective of this study was to investigate the prevalence and predictors of insufficient 25(OH)D concentrations in athletes. Six hundred three Swiss athletes were assessed. 25(OH)D was analysed by high-performance liquid chromatography (HPLC). A standardized questionnaire was used to gather information about potential predictors for 25(OH)D concentrations; 50.5% showed insufficient 25(OH)D concentrations. Differences in predicted probability of insufficient 25(OH)D were found for those vitamin D supplemented (42%) versus not supplemented (52%), in those performing indoor (58%) versus outdoor sports (43%), and during the sun-deprived seasons of fall (49%), winter (70%) and spring (57%) compared with summer (17%). Higher BMI z-scores and age were associated with higher 25(OH)D concentrations. In conclusion, insufficient 25(OH)D concentrations were common among athletes especially at a younger age, among those not supplemented, in athletes who trained indoors, and during the sun-deprived seasons. Because the prevalence of insufficient 25(OH)D concentrations in this study was high, regular supplementation in athletes may be indicated, except perhaps during the summer season. Further research is needed to determine which 25(OH)D concentrations lead to optimal health and performance in athletes.

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<![CDATA[Peak velocity and its time limit are as good as the velocity associated with VO2max for training prescription in runners]]> https://www.researchpad.co/article/5c19af85d5eed0c484c46bcf

This study compared the effects of 4 weeks of training prescribed by peak velocity (V peak ) or velocity associated with maximum oxygen uptake (vVO 2max ) in moderately trained endurance runners. Study participants were 14 runners (18–35 years) randomized into 2 groups, named group VO 2 (GVO 2 ) and group V peak (GVP). The GVO 2 had training prescribed by vVO 2max and its time limit (t lim ), whereas the GVP had training prescribed by V peak and its t lim . Four tests were performed on a treadmill: 2 maximum incremental for V peak and vVO 2max and 2 for their t lim . Performance (10 km) was evaluated on a 400 m track. Evaluations were repeated after 4 weeks of endurance training. The results showed a significant effect of training on V peak [GVP (16.7±1.2 17.6±1.5 km . h −1 ), GVO 2 (17.1±1.9–17.7±1.6 km·h −1 )]; vVO 2max [GVP (16.4±1.4–17.0±1.3 km·h −1 ), GVO 2 (17.2±1.7–17.5±1.9 km·h −1 )]; and 10 km performance [GVP (41.3±2.4–39.9±2.7 min), GVO 2 (40.1±3.4–39.2±2.9 min)]. The V peak highly correlated with performance in both pre- and post-training in GVP (–0.97;–0.86) and GVO 2 (–0.95;–0.94), as well as with vVO 2max in GVP (–0.82;–0.88) and GVO 2 (–0.99; –0.98). It is concluded that training prescribed by V peak promoted similar improvements compared to training prescribed by vVO 2max . The use of V peak is recommended due to its practical application and the low cost of determination.

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<![CDATA[Estimation of Relative Load From Bar Velocity in the Full Back Squat Exercise]]> https://www.researchpad.co/article/5c19af8fd5eed0c484c46da4

The use of bar velocity to estimate relative load in the back squat exercise was examined. 80 strength-trained men performed a progressive loading test to determine their one-repetition maximum (1RM) and load-velocity relationship. Mean (MV), mean propulsive (MPV) and peak (PV) velocity measures of the concentric phase were analyzed. Both MV and MPV showed a very close relationship to %1RM (R 2 =0.96), whereas a weaker association (R 2 =0.79) and larger SEE (0.14 vs. 0.06 m·s −1 ) were found for PV. Prediction equations to estimate load from velocity were obtained. When dividing the sample into 3 groups of different relative strength (1RM/body mass), no differences were found between groups for the MPV attained against each %1RM. MV attained with the 1RM was 0.32±0.03 m·s −1 . The propulsive phase accounted for ~82% of concentric duration at 40% 1RM, and progressively increased until reaching 100% at 1RM. Provided that repetitions are performed at maximal intended velocity, a good estimation of load (%1RM) can be obtained from mean velocity as soon as the first repetition is completed. This finding provides an alternative to the often demanding, time-consuming and interfering 1RM or nRM tests and allows implementing a velocity-based resistance training approach.

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<![CDATA[Effect of Core Training on Trunk Flexor Musculature in Male Soccer Players]]> https://www.researchpad.co/article/5c19af9ad5eed0c484c46fc4

The present study aimed to elucidate the effect of core training on trunk flexor musculature in athletes. Twenty-eight collegiate male soccer players were randomly assigned to three groups: a training group that performed core exercises with wheeled platforms (WP), a training group that performed body mass-based core exercise (BME), and a control group that did not perform core exercise training (CON). WP and BME trained twice a week for 10 weeks. The WP performed 8–14 exercises with wheeled platforms. BME conducted four core exercises to failure. Before and after the intervention, trunk segment lean body mass (LBM) was measured using a whole-body dual-energy X-ray absorptiometry scanner. Muscle thicknesses (MTs) of the rectus abdominis (RA), external oblique, internal oblique (IO), and transverse abdominis were determined with an ultrasound apparatus. No significant changes for any measured variables were found in CON. In both training groups, the trunk segment LBM was significantly increased through the intervention. While MT for IO significantly increased in the two training groups, significant increases in MT for RA were found in only WP. For collegiate soccer players, the core training programs adopted here can be effective in increasing trunk segment LBM, but the effectiveness on the trunk flexor muscularity differs between the two training modalities.

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<![CDATA[Metabolic and Performance Responses to Sprint Exercise under Hypoxia among Female Athletes]]> https://www.researchpad.co/article/5c19af7cd5eed0c484c46a12

The present study determined metabolic and performance responses to repeated sprint exercise under hypoxia among female team-sport athletes. Fifteen female athletes (age, 20.7±0.2 years; height, 159.6±1.7 cm; body weight, 55.3±1.4 kg) performed two exercise trials under either a hypoxic [HYPO; fraction of inspired oxygen (F i O 2 ), 14.5%] or normoxic (NOR; F i O 2 , 20.9%) condition. The exercise consisted of two sets of 8×6-s maximal sprint (pedaling). The average power output was not significantly different between trials for set 1 ( P =0.89), but tended to be higher in the NOR trial for set 2 ( P =0.05). The post-exercise blood lactate concentrations were significantly higher in the HYPO trial than that in the NOR trial ( P <0.05). Exercise significantly increased serum growth hormone (GH) and cortisol concentrations ( P <0.01 for both hormones), with no difference between the trials. In conclusion, repeated short-duration sprints interspaced with 30-s recovery periods in moderate hypoxia caused further increase in blood lactate compared with the same exercise under normoxic conditions among female team-sport athletes. However, exercise-induced GH and cortisol elevations or power output during exercise were not markedly different regardless of the different levels of inspired oxygen.

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<![CDATA[The Effect of First-Step Techniques from the Staggered Stance in American Football]]> https://www.researchpad.co/article/5c19af91d5eed0c484c46e03

The purpose of this study was to evaluate 3 different starting techniques from the staggered stance with regards to sprint time, reaction time, linear impulse and power. 11 male amateur American football players volunteered to participate in a testing session consisting of twelve 5 m sprints, 4 in each technique (normal (NORM), backwards false step (BFS) and forwards false step (FFS)) in random order. Sprint starts were performed on force plates to investigate ground reaction forces, reaction time and total sprint time. Analysis showed significant differences in sprint times, with NORM (1.77±0.10 s) being faster than FFS (1.81±0.12 s) and BFS (2.01±0.13 s), and FFS being faster than BFS, although no differences were found in reaction time. In terms of mean force and power, NORM (331.1±39.2N, 542.2±72.3W) and FFS (320.8±43.2N, 550.9±81.4W) were significantly larger than BFS (256.9±36.2N, 443.5±61.1W). This indicates that when starting from a staggered stance, the BFS is inferior to the others and should be avoided. However, since the force profiles of the NORM and the FFS were similar, the differences in sprint time could arise from a technique bias towards the NORM start.

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<![CDATA[Pre-season Fitness Level and Injury Rate in Professional Soccer – A Prospective Study]]> https://www.researchpad.co/article/5c19af7ed5eed0c484c46a71

The aim of the present study was to assess prospectively the effect of pre-season fitness on injury rate during the competitive season among professional soccer players. Thirty-one players participated in the study during two consecutive competitive seasons (2015–16 and 2016–17; a squad of 22 players in each season). During the 6-week pre-season training period (8 training sessions and a friendly match every week, 14–18 training hours/week) there was a significant improvement in VO 2 max, a significant increase in ideal and total sprint time and no change in vertical jump, flexibility and repeated sprint-test performance decrement. During the two consecutive seasons, 28 injuries were recorded. Ten injuries were classified as mild (missing 3–7 days of practice/match), 8 as moderate (missing 8–28 days) and 10 as severe (missing >28 days). The rate of match injuries was higher (9.4 per 1000 match hours) compared to practice injuries (4.7 per 1000 training hours). Most injuries were overuse injuries (72%) of the lower limbs (71%). Most of match injuries occurred during the last 15 min of each half. There were no differences in fitness characteristics in the beginning of pre-season training between injured and non-injured players. However, improvements in VO 2 max during the pre-season training period were significantly lower among injured players (0.9±5.5%) compared to non-injured players (10.4±6.5%, p<0.05). Our results emphasize the importance of pre-season training in professional soccer players not only for improvement in fitness but also for injury prevention during the following competitive season.

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