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1.
Injuries stemming from shoulder instability are very common among athletes participating in contact sports, such as football. Previous research has shown that increased laxity negatively affects the function of the sensorimotor system potentially leading to a pathological cycle of shoulder dysfunction. Currently, there are no data detailing such effects among football players. Therefore, the purpose of this study was to examine the differences in upper extremity sensorimotor control among football players compared with that of a control group. Forty-five collegiate football players and 70 male control subjects with no previous experience in contact sports participated. All the subjects had no recent history of upper extremity injury. Each subject performed three 30-second upper extremity balance trials on each arm. The balance trials were conducted in a single-arm push-up position with the test arm in the center of a force platform and the subjects' feet on a labile device. The trials were averaged, and the differences in radial area deviation between groups were analyzed using separate 1-way analyses of variance (p < 0.05). The football players showed significantly more radial area deviation of the dominant (0.41 ± 1.23 cm2, p = 0.02) and nondominant arms (0.47 ± 1.63 cm2, p = 0.03) when compared with the control group. These results suggest that football players may have decreased sensorimotor control of the upper extremity compared with individuals with no contact sport experience. The decreased upper extremity sensorimotor control among the football players may be because of the frequent impacts accumulated during football participation. Football players may benefit from exercises that target the sensorimotor system. These findings may also be beneficial in the evaluation and treatment of various upper extremity injuries among football players.  相似文献   

2.
Compared with lower extremity plyometrics, data concerning the loads and intensity associated with upper extremity plyometrics are limited. The purpose of this study was to compare vertical ground reaction force (vGRF) characteristics between the clap push-up and box drop push-ups from 3.8 cm (BD1), 7.6 cm (BD2), and 11.4 cm (BD3) heights and limbs (dominant, nondominant). Twenty-two healthy active male subjects (age 25.9 ± 1.3 years, height 1.8 ± 0.08 m, mass 87.6 ± 12 kg) performed 4 repetitions of each push-up variation in a random order. Four dependent variables, peak vGRF, time-to-peak vGRF, loading rate (LR), and propulsion rate (PR) were calculated for each extremity. Statistical analysis consisted of separate limb by variation repeated measures analysis of variance. In addition, ground contact time (GCT) was statistically compared between variations. The GCT for the clap push-up (p = 0.033) was significantly less than that for BD1 and BD2. No significant differences were revealed for time-to-peak vGRF (p = 0.717). Peak vGRF was significant between dominant and nondominant limbs (p = 0.045). Post hoc analysis of a significant limb by variation interaction in LR (p < 0.001) revealed the dominant limb to be significantly greater than the nondominant one in all 4 push-up variations. Furthermore, for both limbs, the clap LR was significantly greater than BD1, BD2, and BD3. The clap PR was significantly greater than BD1, BD2, and BD3. These data add rationale for determining upper extremity plyometric progression. The peak vGRFs are similar, and altering the box height did not affect peak vGRF. In contrast, the clap demonstrated the highest LR and PR suggesting that it may be a more powerful exercise than BD1, BD2, and BD3. The higher LR (Clap and BD3) for the dominant extremity illustrates bilateral disparity in the rate of eccentric loading.  相似文献   

3.
Quantification of rehabilitation progress is necessary for accurately assessing clinical treatments. A three-dimension (3D) upper extremity (UE) kinematic model was developed to obtain joint angles of the trunk, shoulder and elbow using a Vicon motion analysis system. Strict evaluation confirmed the system's accuracy and precision. As an example of application, the model was used to evaluate the upper extremity movement of eight hemiparetic stroke patients with spasticity, while completing a set of reaching tasks. Main outcome measures include kinematic variables of movement time, range of motion, peak angular velocity, and percentage of reach where peak velocity occurs. The model computed motion patterns in the affected and unaffected arms. The unaffected arm showed a larger range of motion and higher angular velocity than the affected arm. Frequency analysis (power spectrum) demonstrated lower frequency content for elbow angle and angular velocity in the affected limb when compared to the unaffected limb. The model can accurately quantify UE arm motion, which may aid in the assessment and planning of stroke rehabilitation, and help to shorten recovery time.  相似文献   

4.
Repeat measurements in 69 young adults were performed to assess the test-retest reliability and the 95% confidence interval of the difference in score between paired observations (MDC95) of a Wingate test as abbreviated for field sport participants (test of a 15-second duration [15-secT]). Test-retest reliability was excellent for peak power output (PPO) and mean power output (MPO), independently of their mode of expression and was moderate for the fatigue index (FI). The standard errors of measurement (SEM) for absolute, relative, and derived PPO and MPO values ranged from 2.6 to 3.7%, all being smaller than the corresponding smallest worthwhile change (SWC). In contrast, FI values were rated as "marginal," with an SEM (9.6%) greater than the SWC (1.7). The range of MDC95 values for PPO and MPO were 9.9-10.4 and 7.37-7.42%, respectively. The absolute MPO showed the highest test-retest reliability and was the most effective in detecting real change. A second phase of the study evaluated the criterion-related validity of the 15-secT in 43 young men who performed 15-secT and standard 30-second Wingate anaerobic test (30-secT) in random order, on 2 separate occasions. There were no significant intertest differences in absolute, relative, or derived PPO. However, the FI for the 30-secT was greater than that for the 15-secT. Intertest correlations were highly significant for both MPOs and FIs. These findings suggest that the abbreviated Wingate test offers a reliable and valid tool for the evaluation of PPO and MPO, at least in young physical education students.  相似文献   

5.
Because of the recognized link between core stability and back and lower extremity injury in sport, additional field tests that assess the strength and power component of core stability are needed to identify athletes at risk of such injury. To that end, we developed and tested the reliability of the front and side abdominal power tests (FAPT and SAPT), which were adapted from plyometric medicine ball exercises. The FAPT and SAPT were performed by explosively contracting the core musculature using the arms as a lever to project a medicine ball. Twenty-four untrained young women (aged 20.9 +/- 1.1 year) completed three trials each of the FAPT and SAPT on separate nonconsecutive days. The average distance the medicine ball was projected on each day was recorded; power was inferred from this measure. There was an approximately 3% increase in the mean distance between the testing sessions for the FAPT and SAPT; this was not significant and indicates there was no learning effect in the measurement protocol. Heteroscedasticity was present in the SAPT data but not the FAPT data. For the FAPT, the intraclass correlation coefficient was 0.95, standard error of measurement was 24 cm, and random error using the limits of agreement method was 67.5 cm. For the SAPT, the intraclass correlation coefficient was 0.93, mean coefficient of variation was 9.8%, and the limits of agreement ratio was 36.8%. The FAPT and SAPT displayed excellent test-retest reliability, as well as acceptable measurement error. These findings suggest the FAPT and SAPT are reliable tests and may be used to assess the power component of core stability in young women.  相似文献   

6.
7.
This study was performed to determine the test-retest reliability and the relationship between 2 tests of trunk flexor muscular endurance-a prone bridge and a modified V-sit. Hold times (in seconds) were measured on 60 healthy volunteers from a University community (17 men, 43 women). Both tests were performed at 1-week intervals. The test-retest reliability of each test was assessed with a subgroup of 10 participants during 3 additional testing sessions at 1-week intervals. One examiner collected all data. Intraclass correlation coefficients (2, 1) with the prone bridge were 0.95 and 0.71 with the modified V-sit. The mean hold time was 92.8 ± 44.4 seconds during the prone bridge and 141.7 ± 104.1 seconds during the modified V-sit. Pearson's correlation coefficients between the 2 tests ranged from r = 0.52 (men + women) to r = 0.87 (men only). Intersession reliability with a single examiner was higher with the prone bridge compared with that in the modified V-sit. Modifications to the V-sit resulted in a lower test-retest reliability than was previously reported. Correlations between prone bridge and modified V-sit test scores were low, which may be attributable to the differences in the level of trunk flexor muscle activation between the tests.  相似文献   

8.
Variation in upper limb long bone cross‐sectional properties may reflect a phenotypically plastic response to habitual loading patterns. Structural differences between limb bones have often been used to infer past behavior from hominin remains; however, few studies have examined direct relationships between behavioral differences and bone structure in humans. To help address this, cross‐sectional images (50% length) of the humeri and ulnae of university varsity‐level swimmers, cricketers, and controls were captured using peripheral quantitative computed tomography. High levels of humeral robusticity were found in the dominant arms of cricketers, and bilaterally among swimmers, whereas the most gracile humeri were found in both arms of controls, and the nondominant arms of cricketers. In addition, the dominant humeri of cricketers were more circular than controls. The highest levels of ulnar robusticity were also found in the dominant arm of cricketers, and bilaterally amongst swimmers. Bilateral asymmetry in humeral rigidity among cricketers was greater than swimmers and controls, while asymmetry for ulnar rigidity was greater in cricketers than controls. The results suggest that more mechanically loaded upper limb elements––unilaterally or bilaterally––are strengthened relative to less mechanically loaded elements, and that differences in mechanical loading may have a more significant effect on proximal compared to distal limb segments. The more circular humerus in the dominant arm in cricketers may be an adaptation to torsional strain associated with throwing activities. The reported correspondence between habitual activity patterns and upper limb diaphyseal properties may inform future behavioral interpretations involving hominin skeletal remains. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

9.
The aims of the present study were: (a) to determine the number of familiarization trials required to establish a high degree of reliability in measures of power output during maximal intermittent cycling; and (b) to examine the reliability of those same measures after familiarization had been established. On separate days over a 3-week period, 2 groups of 7 recreationally active men completed 8 trials of 1 of 2 maximal (20 x 5-second) intermittent cycling tests with contrasting recovery periods (10-seconds or 30-seconds). Significant (p < 0.05) between-trial differences were detected in post-hoc tests involving trials 1 and 2 only. Within-subject test-retest reliability was therefore assessed across trials 3-8. Apart from values of maximum power output in Protocol 1 (10-second recovery periods), all remaining measures of power output showed high degrees of within-subject test-retest reliability (coefficient of variation: 2.4-3.7%). The results of the present study indicate that in subjects unfamiliar with maximal intermittent cycling, high degrees of reliability in many performance measures can be achieved following the completion of 2 familiarization trials.  相似文献   

10.
Rotator cuff function is critical to the overhead athlete. Rotator cuff power is felt to be important in the overhead athlete during the throwing motion. Little research exists regarding torque acceleration energy (TAE) in overhead athletes. Twenty-five males were divided into 2 groups consisting of overhead athletes (pitchers) (n = 12) and nonoverhead athletes (controls) (n = 13). All participants were given a concentric velocity spectrum isokinetic test at speeds of 60 degrees (1.05 r), 180 degrees (3.16 r), and 300 degrees.s(-1) (5.26 r) to both the dominant and nondominant shoulder internal and external rotators. Significant differences were found for all internal rotator TAE scores (p = 0.000-0.016), at each of the 3 velocities, when comparing dominant to nondominant arms of both overhead athletes and nonoverhead athletes. Only 60 degrees.s(-1) (1.05 r) was found to be different during external rotation TAE testing of the overhead athletes (p = 0.027) but was not found in the control subjects. Post hoc analysis revealed no differences between dominant or nondominant TAE scores when comparisons were made between overhead athletes and controls. Results may reveal that power of the rotator cuff muscles may not be a critical component of the overhead throwing motion.  相似文献   

11.
Transition of data acquisition out of the laboratory, into the real world offers a previously inaccessible perspective of physical function. This proves to be beneficial when assessing surgical intervention, especially after a traumatic brachial plexus injury (BPI) causing loss of motor function in an upper extremity (UE). Moving towards the use of real world data in clinical practice as an outcome measure, this study developed a method to report bilateral UE activity in patients with BPI. Three groups of ten subjects each participated in this study—healthy controls, subjects with traumatic BPI prior to surgical treatment (pre-), and subjects who had surgical reconstruction to treat BPI (post-). Subjects wore four activity monitors on bilateral forearms and upper arms for four days. Tri-axial acceleration data were used to calculate asymmetry indices for forearm and upper arm usage. Analysis revealed a bimodal distribution in the post- group, prompting division of this group into two subgroups based on injury type: pan-plexus and upper trunk. While median asymmetry indices at the forearm and upper arm were decreased in the post- group when compared to the pre- group, these differences were not significant. Compared to controls, the pre-surgery group (p < 0.0001, p < 0.0001) and post-surgery group with pan-plexus injuries (p = 0.0074, p = 0.0242) both exhibited statistically significant differences in forearm and upper arm asymmetry, respectively. Further investigation to establish clinically significant differences in asymmetry index is warranted. Importantly, analyzing the activity of UEs following treatment of a BPI provides objective real world evidence of function.  相似文献   

12.
In an effort to evaluate potential peripheral adaptations to training, maximal metabolic vasodilation was studied in the dominant and nondominant forearms of six tennis players and six control subjects. Maximal metabolic vasodilation was defined as the peak forearm blood flow measured after release of arterial occlusion, the reactive hyperemic blood flow (RHBF). Two ischemic stimuli were employed in each subject: 5 min of arterial occlusion (RHBF5) and 5 min of arterial occlusion coupled with 1 min of ischemic exercise (RHBF5ex). RHBF and resting forearm blood flows were measured using venous occlusion strain-gauge plethysmography (ml X min-1 X 100 ml-1). Resting forearm blood flows were similar in both arms of both groups. RHBF5ex was similar in both arms of our control group (dominant, 40.8 +/- 1.2 vs. nondominant, 40.9 +/- 2.1). However, RHBF5ex was 42% higher in the dominant than in the nondominant forearms of our tennis player population (dominant, 48.7 +/- 4.0 vs. nondominant, 34.4 +/- 3.4; P less than 0.05). This intraindividual difference in peak forearm blood flows was not secondary to improved systemic conditioning since the maximal O2 consumptions in the two study groups were similar (controls, 45.4 +/- 3.9 vs. tennis players, 46.1 +/- 1.7). These findings suggest a primary peripheral cardiovascular adaptation to exercise training in the dominant forearms of the tennis players resulting in a greater maximal vasodilatation.  相似文献   

13.
The primary aim of this study was to determine reliability and factorial validity of squat (SJ) and countermovement jump (CMJ) tests. The secondary aim was to compare 3 popular methods for the estimation of vertical jumping height. Physical education students (n = 93) performed 7 explosive power tests: 5 different vertical jumps (Sargent jump, Abalakow's jump with arm swing and without arm swing, SJ, and CMJ) and 2 horizontal jumps (standing long jump and standing triple jump). The greatest reliability among all jumping tests (Cronbach's alpha = 0.97 and 0.98) had SJ and CMJ. The reliability alpha coefficients for other jumps were also high and varied between 0.93 and 0.96. Within-subject variation (CV) in jumping tests ranged between 2.4 and 4.6%, the values being lowest in both horizontal jumps and CMJ. Factor analysis resulted in the extraction of only 1 significant principal component, which explained 66.43% of the variance of all 7 jumping tests. Since all jumping tests had high correlation coefficients with the principal component (r = 0.76-0.87), it was interpreted as the explosive power factor. The CMJ test showed the highest relationship with the explosive power factor (r = 0.87), that is, the greatest factorial validity. Other jumping tests had lower but relatively homogeneous correlation with the explosive power factor extracted. Based on the results of this study, it can be concluded that CMJ and SJ, measured by means of contact mat and digital timer, are the most reliable and valid field tests for the estimation of explosive power of the lower limbs in physically active men.  相似文献   

14.
Measurement of graded exercise test duration is clinically important and can be assessed by maximal graded exercise testing. Yet, limitations of maximal graded exercise testing exist. An alternative to maximal graded exercise testing is submaximal graded exercise testing. However, no studies have investigated the reliability of a submaximal graded exercise test in the measurement of graded exercise test duration. The purpose of this study was to determine the test-retest reliability and minimal detectable change (MDC) of a novel submaximal graded exercise test in the measurement of graded exercise test duration. Fifteen people (4 men, 11 women) with a mean age of 26.20 years (SD = 9.04) participated in this study. A novel submaximal graded exercise test was used to measure graded exercise test duration for each participant. Endpoints of the test were either 85% of age-predicted maximum heart rate or voluntarily stopping the test, whichever endpoint occurred first. Heart rate and graded exercise test duration were constantly measured throughout the test. Graded exercise test duration was defined as the total duration (minutes) of the test. For all participants, the submaximal graded exercise test was conducted at baseline and 48-72 hours thereafter. The intraclass correlation coefficient for the test-retest reliability of the test in determining graded exercise test duration was 0.94 (95% CI = 0.83-0.98). The MDC of the test in the measurement of graded exercise test duration was 0.86 minutes. The results suggest that clinicians can use this novel submaximal graded exercise test to reliably measure graded exercise test duration with a measurement error, as expressed by the MDC, of 0.86 minutes.  相似文献   

15.
《Ecology and evolution》2021,11(24):17744
Biotic and abiotic factors interact with dominant plants—the locally most frequent or with the largest coverage—and nondominant plants differently, partially because dominant plants modify the environment where nondominant plants grow. For instance, if dominant plants compete strongly, they will deplete most resources, forcing nondominant plants into a narrower niche space. Conversely, if dominant plants are constrained by the environment, they might not exhaust available resources but instead may ameliorate environmental stressors that usually limit nondominants. Hence, the nature of interactions among nondominant species could be modified by dominant species. Furthermore, these differences could translate into a disparity in the phylogenetic relatedness among dominants compared to the relatedness among nondominants. By estimating phylogenetic dispersion in 78 grasslands across five continents, we found that dominant species were clustered (e.g., co‐dominant grasses), suggesting dominant species are likely organized by environmental filtering, and that nondominant species were either randomly assembled or overdispersed. Traits showed similar trends for those sites (<50%) with sufficient trait data. Furthermore, several lineages scattered in the phylogeny had more nondominant species than expected at random, suggesting that traits common in nondominants are phylogenetically conserved and have evolved multiple times. We also explored environmental drivers of the dominant/nondominant disparity. We found different assembly patterns for dominants and nondominants, consistent with asymmetries in assembly mechanisms. Among the different postulated mechanisms, our results suggest two complementary hypotheses seldom explored: (1) Nondominant species include lineages adapted to thrive in the environment generated by dominant species. (2) Even when dominant species reduce resources to nondominant ones, dominant species could have a stronger positive effect on some nondominants by ameliorating environmental stressors affecting them, than by depleting resources and increasing the environmental stress to those nondominants. These results show that the dominant/nondominant asymmetry has ecological and evolutionary consequences fundamental to understand plant communities.  相似文献   

16.
Practitioners training the older adult may benefit from a low-cost, easy-to-administer field test of upper body power. This study evaluated validity and reliability of the seated medicine ball throw (SMBT) in older adults. Subjects (n = 33; age 72.4 ± 5.2 years) completed 6 trials of an SMBT in each of 2 testing days and 2 ball masses (1.5 and 3.0 kg). Subjects also completed 6 trials of an explosive push-up (EPU) on a force plate over 2 testing days. Validity was assessed via a Pearson Product-Moment correlation (PPM) between SMBT and EPU maximal vertical force. Reliability of the SMBT was determined using PPMs (r), Intraclass correlation (ICC, R) and Bland-Altman plots (BAPs). For validity, the association between the SMBT and the EPU revealed a PPM of r = 0.641 and r = 0.614 for the 1.5- and 3.0-kg medicine balls, respectively. Test-retest reliability of the 1.5- and 3.0-kg SMBT was r = 0.967 and r = 0.958, respectively. The ICC values of the 1.5- and 3.0-kg SMBT were R = 0.994 and 0.989, respectively. The BAPs revealed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference. Test-retest reliability for the EPU was r = 0.944, R = 0.969. The BAPs showed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference, for both medicine ball throws. In conclusion, for the older adult, the SMBT appears to be highly reliable test of upper body power. Its validity relative to the maximal force exerted during the EPU is modest. The SMBT is an inexpensive, safe, and repeatable measure of upper body power for the older adult.  相似文献   

17.
The aim of the study was to investigate whether there was a difference in the electromyographic (EMG) activity of human shoulder muscles between the dominant and nondominant side during movement and to explore whether a possible side-difference depends on the specific task. We compared the EMG activity with surface and intramuscular electrodes in eight muscles of both shoulders in 20 healthy subjects whose hand preference was evaluated using a standard questionnaire. EMG signals were recorded during abduction and external rotation. During abduction, the normalized EMG activity was significantly smaller on the dominant side compared to the nondominant side for all the muscles except for infraspinatus and lower trapezius (P 相似文献   

18.
This study examined the muscular activation patterns produced while riding the Step 'n Go, a tricycle powered by a reciprocating vertical motion and typically used by individuals with cognitive, orthopedic, and neuromuscular conditions. Seven normal, adult subjects were tested at three power levels (75, 100, and 125 W) during seated and standing riding. Eight lower extremity muscles were examined with surface electromyography. Results showed that the major power producing muscles for this device were the gluteus maximus, vastis lateralis and medialis, rectus femoris, and tibialis anterior. At the highest power level, peak and mean muscular activation in these muscles were substantially lower (17–38%) while riding standing compared to seated, and seems to reflect the benefit of body weight for power production while standing. At the lowest power level, the peak and mean muscle activation differences between positions were less remarkable, and in some cases the standing values were greater than seated. This suggests that significant muscular effort was required to maintain standing posture and balance when riding at low power levels. Individuals able to perform vastis lateralis and medialis intensive activities, such as the concentric portion of a squat or using a stepping machine (Stair Master), should be able to comfortably ride the Step 'n Go at low power levels.  相似文献   

19.
In studies of physical performance comprising muscle strength and power, a vertical jump is a test method that frequently is used. It is important to have access to accurate measuring tools providing data with high reproducibility. Studies have shown that body composition also may play an important part in physical performance. The purpose of this study was to determine test-retest reliability for 3 different kinds of vertical jumps and to correlate jump height with body composition. Thirty-four normally trained subjects (women n = 17) between 18 and 25 years participated. Test-retest, on 3 kinds of vertical jumps, was performed with a median of 7 days between jumps. Methods used were a countermovement jump (CMJ) on a contact mat, with and without arm swing, and an Abalakow jump (AJ) using measuring tape, with arm swing. Body composition was assessed with the use of bioelectric impedance analysis. The results showed that high intraclass correlation coefficients (ICCs) were observed between testing occasions for all 3 vertical jumps (ICC between 0.48 and 0.88). The AJ in women presented the lowest ICC. Also the correlation between CMJ and AJ was high (rs = 0.88). Moderate-to-high correlations could be shown between body composition and CMJ in women (rs = -0.57-0.76). In conclusion, very high test-retest reliability for CMJ on a contact mat was found. For the AJ using a measuring tape, ICC were overall high, but a moderate nonsignificant ICC were found in women, indicating poor reproducibility. The data from the CMJ and AJ may be compared if approximately 25% of the AJ value is subtracted. In practice, this means that vertical jump tests have high reproducibility and can be used as measures of power development.  相似文献   

20.
Measuring physical fitness becomes more important. Yet most instruments depend upon the function of the lower extremities. Hence, we investigated whether an adapted submaximal arm crank test on an ergometer for the upper body is reliable to use, and if the submaximal test for the arm crank ergometer is valid compared to the test on the bicycle ergometer. Different types of reliability measures of the adapted submaximal test on an arm crank ergometer were assessed in healthy volunteers, such as test-retest, interobserver, interergometer, and between arm crank and bicycle ergometer. A crossover design was used. The measurements were proportionally distributed over 30 volunteers. Based on the intraclass correlation coefficient (ICC) and the magnitude of within-person differences, we revealed a good reliability of the submaximal test. For the test-retest reliability, the ICC was 0.76, the interobserver reliability was 0.82, and the interergometer reliability 0.63. In addition, the criterion validity was also tested by comparing the calculated VO2max during the submaximal test on the arm crank ergometer and on the bicycle ergometer. Between VO2max on the arm crank and bicycle ergometer, an ICC of 0.64 was found. The results of the submaximal test on the arm crank ergometer are reliable and valid as compared with those on the bicycle crank ergometer. We showed that the submaximal test on the arm crank ergometer is suitable for measuring physical fitness in healthy people. We expect that disabled people can use this submaximal test on the arm crank ergometer for measuring their physical fitness, also.  相似文献   

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