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1.
The purpose of this study was to assess the within- and between-session reliability of lower limb biomechanics in two sport-specific sidestep cutting tasks performed by elite female handball and football (soccer) athletes. Moreover, we aimed at determining the minimum number of trials necessary to obtain a reliable measure. Nineteen elite female handball and 22 elite female football (soccer) athletes (M ± SD: 22 ± 4 yrs old, 168 ± 5 cm, 66 ± 8 kg) were tested. The reliability was quantified by intra-class correlations (ICCs), typical error and Spearman’s rank correlation. Only minor improvements in ICC values were seen when increasing the number of trials from 3 to 5. Based on trials 1–3, all variables showed good to excellent within-session reliability (M ICC: 0.91, 95% CI: 0.89–0.93), fair to good between-session reliability (M ICC: 0.73, 95% CI: 0.70–0.76), moderately positive between-session rank correlation coefficients (M: 0.72, 95% CI: 0.69–0.76). A few frontal plane biomechanical variables displayed lower between-session reliability in the football task compared with the handball task. The moderately positive between-session ranking and practically small typical error implies that the measurements could reliably reproduce the ranking of individuals in multiple-session studies. Adequate reliability could be attained from 3 trials, with only minor improvements when adding more trials.  相似文献   

2.
ABSTRACT

Purpose: This study examined the test-retest reliability and feasibility of select fitness assessments in 7–12 year old children on the autism spectrum. Method: Participants (N = 14; n = 1 female; Mage = 9.5 ± 1.7 years) completed 7 fitness assessments, administered in a random order, on two occasions: Bruce protocol; Modified 6-minute walk test (M6MWT); Wingate anaerobic cycling test; muscle power sprint test (MPST); sit & reach; standing long jump; and grip strength. Intraclass correlations (two-way mixed with absolute agreement) were computed to examine test-retest reliability. Feasibility was assessed by questionnaire following the first administration of each test. Results: The Wingate (ICC = .956), standing long jump (ICC = .925), grip strength (ICC = .913), and sit and reach (ICC = .829) tests demonstrated good- to- excellent reliability, while the Bruce protocol (ICC = .811), M6MWT (ICC = .510), and MPST (ICC = .703) demonstrated moderate- to- good reliability based on the 95% confidence intervals of the ICC. All tests demonstrated assessor-rated feasibility scores of 70/100 or higher and child-rated feasibility scores of 66/100 or higher. Conclusion: The results demonstrate moderate- to excellent test-retest reliability for select fitness tests. Short, single-instruction (e.g., standing long jump) tests may be more reliable than lengthier assessments (e.g., M6MWT) in this population. Implications of this work include the ability of practitioners and researchers to feasibly and reliably measure the fitness of school-aged children on the autism spectrum for ongoing health and behavioural monitoring and intervention purposes.  相似文献   

3.
Jump performance is considered an important factor in many sports. Thus, strategies such as weightlifting (WL) exercises, traditional resistance training (TRT) and plyometric training (PT) are effective at improving jump performance. However, it is not entirely clear which of these strategies can enable greater improvements on jump height. Thus, the purpose of the meta-analysis was to compare the improvements on countermovement jump (CMJ) performance between training methods which focus on WL exercises, TRT, and PT. Seven studies were included, of which one study performed both comparison. Therefore, four studies comparing WL exercises vs. TRT (total n = 78) and four studies comparing WL exercises vs. PT (total n = 76). The results showed greater improvements on CMJ performance for WL exercises compared to TRT (ESdiff: 0.72 ± 0.23; 95%CI: 0.26, 1.19; P = 0.002; Δ % = 7.5 and 2.1, respectively). The comparison between WL exercises vs. PT revealed no significant difference between protocols (ESdiff: 0.15 ± 0.23; 95%CI: ?0.30, 0.60; P = 0.518; Δ % = 8.8 and 8.1, respectively). In conclusion, WL exercises are superior to promote positive changes on CMJ performance compared to TRT; however, WL exercises and PT are equally effective at improving CMJ performance.  相似文献   

4.
Anterior cruciate ligament (ACL) injury prevention programmes have not been as successful at reducing injury rates in women’s basketball as in soccer. This randomised controlled trial (ClinicalTrials.gov #NCT02530333) compared biomechanical adaptations in basketball and soccer players during jump-landing activities after an ACL injury prevention programme. Eighty-seven athletes were cluster randomised into intervention (6-week programme) and control groups. Three-dimensional biomechanical analyses of drop vertical jump (DVJ), double- (SAG-DL) and single-leg (SAG-SL) sagittal, and double- (FRONT-DL) and single-leg (FRONT-SL) frontal plane jump landing tasks were tested before and after the intervention. Peak angles, excursions, and joint moments were analysed using two-way MANCOVAs of post-test scores while controlling for pre-test scores. During SAG-SL the basketball intervention group exhibited increased peak knee abduction angles (p = .004) and excursions (p = .003) compared to the basketball control group (p = .01) and soccer intervention group (p = .01). During FRONT-SL, the basketball intervention group exhibited greater knee flexion excursion after training than the control group (p = .01), but not the soccer intervention group (p = .11). Although women’s soccer players exhibit greater improvements in knee abduction kinematics than basketball players, these athletes largely exhibit similar biomechanical adaptations to ACL injury prevention programmes.  相似文献   

5.
Lower extremity injuries have immediate and long-term consequences. Lower extremity movement assessments can assist with identifying individuals at greater injury risk and guide injury prevention interventions. Movement assessments identify similar movement characteristics and evidence suggests large magnitude kinematic relationships exist between movement patterns observed across assessments; however, the magnitude of the relationships for electromyographic (EMG) measures across movement assessments remains largely unknown. This study examined relationships between lower extremity kinematic and EMG measures during jump landings and single leg squats. Lower extremity three-dimensional kinematic and EMG data were sampled from healthy adults (males = 20, females = 20) during the movement assessments. Pearson correlations examined the relationships of the kinematic and EMG measures and paired samples t-tests compared mean kinematic and EMG measures between the assessments. Overall, significant moderate correlations were observed for lower extremity kinematic (ravg = 0.41, rrange = 0.10–0.61) and EMG (ravg = 0.47, rrange = 0.32–0.80) measures across assessments. Kinematic and EMG measures were greater during the jump landings. Jump landings and single leg squats place different demands on the body and necessitate different kinematic and EMG patterns, such that these measures are not highly correlated between assessments. Clinicians should, therefore, use multiple assessments to identify aberrant movement and neuromuscular control patterns so that comprehensive interventions can be implemented.  相似文献   

6.
This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.  相似文献   

7.
Abstract

This study aimed to investigate the effect of whole body vibration (WBV) training on the knee kinematics and neuromuscular control after single-legged drop landings. Surface electromyographic (EMG) activity of the rectus femoris and hamstring muscles and knee and ankle accelerometry signals were acquired from 42 healthy volunteers. Participants performed three pre-test landings and after a recovery period of three minutes, they completed one set of six bouts of WBV each of one minute duration (30 Hz – 4 mm), followed by a single-leg drop landing. After the WBV intervention no significant changes were observed in the kinematic outcomes measured, although the time to stabilise the lower-limb was significantly lower after the vibration training (F(8,41) = 6.55; P < 0.01). EMG analysis showed no significant differences in the amplitude of rectus femoris or hamstring muscles after WBV training, however, significant differences in EMG frequency of the rectus femoris were found before (F(8,41) = 7.595; P < 0.01) and after toe-down (F(8,41) = 4.440; P < 0.001). Finally, no significant changes were observed in knee or ankle acceleration after WBV. Results suggest that WBV can help to acutely enhance knee neuromuscular control, which may have clinical significance and help in the design of rehabilitation programmes.  相似文献   

8.
The aim of this study was to evaluate the reliability of two long jump tasks and their ability to predict 10 m sprint performance in elite adolescent female athletes. Eight junior national-level female track and field athletes completed three standing (SLJ) and reactive long jumps (RLJ) on portable force plates, followed by three 10 m sprints. Intra-class correlation coefficients (ICC) and coefficients of variation (CV) were calculated to examine reliability. Linear regression results identified the best predictor of average and best 10 m sprint time from the jump kinematic and kinetic measures. The ICCs and CVs indicated good reliability for the majority of kinetic measures however, better reliability was reported for the SLJ. The SLJ was a good predictor of best and average 10 m sprint time, with average horizontal power the best predictor of performance (best; R 2 = 0.751, p = 0.003, Standard Error of Estimate (SEE)% = 2.2 average; R 2 = 0.708, p = 0.005, SEE% = 2.5).  相似文献   

9.
Abstract

Insufficient hip neuromuscular control may contribute to non-contact sport injuries. However, the current evaluative test of hip neuromuscular control, the single-leg squat, requires hip abductor muscle strength to complete. The purpose of this study was to develop the hip control test (HCT) and determine the test’s reliability and construct validity. Nineteen healthy adults visited the laboratory twice. The HCT is a 10-s test of reciprocal toe-tapping accuracy. Both automated and manual HCT ratings were recorded simultaneously during each visit. Additionally, eccentric hip abductor torque was measured. HCT reliability was assessed with intra-class correlation coefficients (ICC). Agreement between automated and manual ratings was determined with Bland–Altman plots. Construct validity was established if HCT performance significantly decreased with a secondary cognitive task (p < 0.05). Bivariate regression determined the relationship between HCT performance and eccentric hip abductor torque. Automated and manual HCT ratings both had moderate reliability (ICC = 0.72) and yielded similar results (limits of agreement = ?1 to 2 taps). The HCT had construct validity (p = 0.001), and no correlation with hip abductor muscle strength (r = 0.213). Thus, the HCT is a reliable and valid test. The HCT is simple to administer and measures hip neuromuscular control separately from strength.  相似文献   

10.
Numerous skill batteries assess fundamental motor skill (e.g., kick, hop) competence. Few skill batteries examine lifelong physical activity skill competence (e.g., resistance training). This study aimed to develop and assess the content validity, test-retest and inter-rater reliability of the “Lifelong Physical Activity Skills Battery”. Development of the skill battery occurred in three stages: i) systematic reviews of lifelong physical activity participation rates and existing motor skill assessment tools, ii) practitioner consultation and iii) research expert consultation. The final battery included eight skills: grapevine, golf swing, jog, push-up, squat, tennis forehand, upward dog and warrior I. Adolescents (28 boys, 29 girls; M = 15.8 years, SD = 0.4 years) completed the Lifelong Physical Activity Skills Battery on two occasions two weeks apart. The skill battery was highly reliable (ICC = 0.84, 95% CI = 0.72–0.90) with individual skill reliability scores ranging from moderate (warrior I; ICC = 0.56) to high (tennis forehand; ICC = 0.82). Typical error (4.0; 95% CI 3.4–5.0) and proportional bias (r = ?0.21, p = .323) were low. This study has provided preliminary evidence for the content validity and reliability of the Lifelong Physical Activity Skills Battery in an adolescent population.  相似文献   

11.
This study aimed to assess the validity and reliability of jump assessments using the MyJump2 application. Eleven junior athletes (15 ± 1.4 years) performed five countermovement (CMJ) and drop jumps (DJ) measured simultaneously by a force platform and MyJump2. Additionally, intra- and inter-day reliability was assessed over two sessions, 7 days apart. Extremely high agreement between MyJump2 and the force platform (intra-class correlation coefficient, ICC ≥ 0.99) and the intra- and inter-operator agreement (ICC = 0.98–0.99) confirmed the validity and reliability of MyJump2. Mean typical errors (coefficient of variation percentage, CV%) within the first and second sessions were 4.9% and 4.5% respectively for CMJs, and 8.0% to 11.8% for DJ outcomes. CMJ height held acceptable inter-day reliability (CV < 10%; ICC > 0.8), while DJ did not. Results supported MyJump2 to be a valid and reliable tool for assessing jumps; however, with variability in DJs in this cohort, appropriate caution should be taken if including in a junior assessment battery.  相似文献   

12.
ABSTRACT

To assess the effects of plyometric jump training (PJT) in female soccer player’s vertical jump height, a review was conducted using the data sources PubMed, MEDLINE, Web Of Science and SCOPUS. Only peer-review articles were included. To qualify for inclusion in the meta-analysis, studies must have included (i) a PJT programme of at least 2 weeks, (ii) cohorts of healthy female soccer players with no restriction for age, (iii) a control group, (iv) a measure of countermovement jump (CMJ). The inverse variance random-effects model for meta-analyses was used. From 7,136 records initially identified through database searching, 8 were eligible for meta-analysis, comprising 9 training groups (n = 99) and 9 control groups (n = 94). The magnitude of the main effect was moderate (ES = 1.01 [95%CI = 0.36–1.66], Z = 3.04, p = 0.002). Sub-group analyses were performed (i.e., PJT frequency, duration and total number of sessions), revealing no significant subgroup differences (p = 0.34–0.96). Among the studies included in this review, none reported injury or other adverse effects. In conclusion, PJT is effective in female soccer players for the improvement of vertical jump height. In future, research must identify specific dose–response relationships following PJT, particularly in the long term.  相似文献   

13.
This study investigated the impact of in-season national team duty on injury rates and player availability in a professional soccer club. Time-loss injuries and exposure time during club and national team duties were recorded prospectively over 5 seasons (2009–2014). A time-loss injury was sustained by 37.7% of squad members participating in national duty, all injuries occurring in match-play. The incidence (per 1000 h exposure) for national team player match-play injuries did not differ (P = 0.608) to that for all players in club competitions: 48.0 (95% CI 20.9–75.5) vs. 41.9 (95% CI 36.5–47.4), incidence rate ratio = 1.2 (CI: 0.8–2.4). The majority (58%) of national team injuries resulted in a layoff ≤1 week. Of all working days lost to injury generally, 5.2% were lost through injury on national duty. Injury incidence in the week following national duty was comparable (P = 0.818) in players participating or not: 7.8 (95% CI 3.6–12.0) vs. 7.1 (95% CI: 4.6–9.6), incidence rate ratio = 1.1 (CI: 0.7–2.7). While approximately 40% of participating players incurred a time-loss injury on national duty, no training injuries were sustained and injuries made up a negligible part of overall club working days lost to injury. Following duty, players had a similar injury risk to peers without national obligations.  相似文献   

14.
ABSTRACT

The aim of the present investigation was to analyze the validity and reliability of a novel iPhone app (CODTimer) for the measurement of total time and interlimb asymmetry in the 5 + 5 change of direction test (COD). To do so, twenty physically active adolescent athletes (age = 13.85 ± 1.34 years) performed six repetitions in the COD test while being measured with a pair of timing gates and CODTimer. A total of 120 COD times measured both with the timing gates and the app were then compared for validity and reliability purposes. There was an almost perfect correlation between the timing gates and the CODTimer app for the measurement of total time (r = 0.964; 95% Confidence interval (CI) = 0.95–1.00; Standard error of the estimate = 0.03 s.; p < 0.001). Moreover, non-significant, trivial differences were observed between devices for the measurement of total time and interlimb asymmetry (Effect size < 0.2, p > 0.05). Similar levels of reliability were observed between the timing gates and the app for the measurement of the 6 different trials of each participant (Timing gates: Intraclass correlation coefficient (ICC) = 0.651–0.747, Coefficient of variation (CV) = 2.6–3.5%; CODTimer: ICC = 0.671–0.840, CV = 2.2–3.2%). The results of the present study show that change of direction performance can be measured in a valid, reliable way using a novel iPhone app.  相似文献   

15.
The current study aimed to assess the validity and test–retest reliability of a linear position transducer when compared to a force plate through a counter-movement jump in female participants. Twenty-seven female recreational athletes (19 ± 2 years) performed three counter-movement jumps simultaneously using the linear position transducer and force plate for validity. In addition, 11 elite female athletes (23 ± 6 years) performed 3 counter-movement jumps with the linear position transducer on three separate days for test–retest reliability. Pearson correlations for jump height between the devices were at a high level (r = .90), with the linear position transducer overestimating jump height by 7.0 ± 2.8 cm. The reliability measured by the linear position transducer resulted in a mean intraclass correlation of .70 for jump height, .90 for peak velocity, and .91 for mean velocity. The linear position transducer was reliable for measuring counter-movement jumps in elite female athletes; however, caution should be taken for one-off jump measures as it may over-estimate jump height.  相似文献   

16.
The aim of this investigation is to assess the effectiveness of a 6-week balance training (BT) protocol, integrated in regular training sessions, on postural sway of young female volleyball players (n = 26, age 13.0 ± 0.2 years) divided into two groups (intervention and control; 13 per group). Trials were performed for bipedal and unipedal stance conditions before and after the BT protocol, using a pressure platform to collect center-of-pressure (COP) time series that were processed to calculate sway area, COP path length, and maximum displacement range in anteroposterior and mediolateral directions. The intervention group exhibited smaller sway areas in eyes closed conditions (intervention = 42.76 mm2, control = 67.60 mm2; p < 0.05) and Romberg quotients (intervention = 1.11 mm, control = 1.82 mm) in bipedal stance, while all the other parameters were unaffected. BT also reduced sway area (intervention = 122.70 mm2, control = 187.18 mm2) and anteroposterior COP displacements (intervention = 20.18 mm, control = 22.38 mm) of the non-dominant limb for single-leg stance. No significant change was found for the dominant limb. Although it is possible to hypothesize a beneficial effect of BT on young athletes, further investigations are required to clarify its actual effect on balance performance with respect to normal volleyball training.  相似文献   

17.
ABSTRACT

Knee joint coordination during jump landing in different directions is an important consideration for injury prevention. The aim of the current study was to investigate knee and hip kinematics on the non-dominant and dominant limbs during landing. A total of 19 female volleyball athletes performed single-leg jump-landing tests in four directions; forward (0°), diagonal (30° and 60°) and lateral (90°) directions. Kinematic and ground reaction force data were collected using a 10-camera Vicon system and an AMTI force plate. Knee and hip joint angles, and knee angular velocities were calculated using a lower extremity model in Visual3D. A two factor repeated measures ANOVA was performed to explore limb dominance and jump direction. Significant differences were seen between the jump directions for; angular velocity at initial contact (p < 0.001), angular velocity at peak vertical ground reaction force (p < 0.001), and knee flexion excursion (p = 0.016). Knee coordination was observed to be poorer in the early phase of velocity-angle plot during landing in lateral direction compared to forward and diagonal directions. The non-dominant limb seemed to have better coordination than the dominant limb during multi-direction jump landing. Therefore, dominant limbs appear to be at a higher injury risk than non-dominant limbs.  相似文献   

18.
Activation of the hamstrings has been discussed as a measure for reducing strain on the ACL during jump landings in alpine skiing. The current study tested the hypothesis that hamstring and quadriceps activation can be voluntarily increased by the athlete. Specifically, two different instructions – to increase hamstring activation or to increase upper-leg co-contraction – were compared to normal landings. Eight members of the German national and junior national squad in freestyle skiing (age 19.6 ± 3.8 years; weight 66.1 ± 13.2 kg; height 172.2 ± 7.7 cm) performed 12 jump landings on a prepared run, 4 with no specific instruction, 4 with the instruction to generally activate the thigh muscles, and 4 with the instruction to specifically activate the hamstrings. Electromyographic (EMG) signals were recorded on the biceps femoris (BF), semitendinosus (ST), vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). EMG activation levels were integrated over three landing phases and analysed with a repeated measures ANOVA. The instruction produced a significant main effect in ST (p = .026), VM (p = .032) and RF (p = .001). Contrary to previous research, the current study suggests that hamstring muscle activation levels can be voluntarily increased during jump landing, particularly in co-activation with its antagonists.  相似文献   

19.
The purpose of the present study was to evaluate the concurrent validity and test-retest repeatability of torso-worn IMU-derived power and jump height in a counter-movement jump test. Twenty-seven healthy recreationally active males (age, 21.9 [SD 2.0] y, height, 1.76 [0.7] m, mass, 73.7 [10.3] kg) wore an IMU and completed three counter-movement jumps a week apart. A force platform and a 3D motion analysis system were used to concurrently measure the jumps and subsequently derive power and jump height (based on take-off velocity and flight time). The IMU significantly overestimated power (mean difference = 7.3 W/kg; P < 0.001) compared to force-platform-derived power but good correspondence between methods was observed (Intra-class correlation coefficient [ICC] = 0.69). IMU-derived power exhibited good reliability (ICC = 0.67). Velocity-derived jump heights exhibited poorer concurrent validity (ICC = 0.72 to 0.78) and repeatability (ICC = 0.68) than flight-time-derived jump heights, which exhibited excellent validity (ICC = 0.93 to 0.96) and reliability (ICC = 0.91). Since jump height and power are closely related, and flight-time-derived jump height exhibits excellent concurrent validity and reliability, flight-time-derived jump height could provide a more desirable measure compared to power when assessing athletic performance in a counter-movement jump with IMUs.  相似文献   

20.
ABSTRACT

Field-based screening methods have a limited capacity to identify high-risk postures during netball-specific landings associated with anterior cruciate ligament (ACL) injuries. This study determined the biomechanical relationship between a single-leg squat and netball-specific leap landing, to examine the utility of including a single-leg squat within netball-specific ACL injury risk screening. Thirty-two female netballers performed single-leg squat and netball-specific leap landing tasks, during which three-dimensional (3D) kinematic/kinetic data were collected. One-dimensional statistical parametric mapping examined relationships between kinematics from the single-leg squat, and the 3D joint rotation and moment data from leap landings. Participants displaying reduced hip external rotation, reduced knee flexion, and greater knee abduction and knee internal rotation angles during the single-leg squat exhibited these same biomechanical characteristics during the leap landing (p < 0.001). Greater ankle dorsiflexion during the single-leg squat was associated with greater knee flexion during landing (p < 0.001). Ankle eversion during the single-leg squat was associated with frontal and transverse plane knee biomechanics during landing (p < 0.001). Biomechanics from the single-leg squat were associated with landing strategies linked to ACL loading or injury risk, and thus may be a useful movement screen for identifying netball players who exhibit biomechanical deficits during landing.  相似文献   

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