Generic muscle parameters are often used in muscle-driven simulations of human movement to estimate individual muscle forces and function. The results may not be valid since muscle properties vary from subject to subject. This study investigated the effect of using generic muscle parameters in a muscle-driven forward simulation on muscle force estimation. We generated a normal walking simulation in OpenSim and examined the sensitivity of individual muscle forces to perturbations in muscle parameters, including the number of muscles, maximum isometric force, optimal fiber length, and tendon slack length. We found that when changing the number of muscles included in the model, only magnitude of the estimated muscle forces was affected. Our results also suggest it is especially important to use accurate values of tendon slack length and optimal fiber length for ankle plantar flexors and knee extensors. Changes in force production by one muscle were typically compensated for by changes in force production by muscles in the same functional muscle group, or the antagonistic muscle group. Conclusions regarding muscle function based on simulations with generic musculoskeletal parameters should be interpreted with caution.
Ming Xiao and Jill Higginson
Samuel Ryan, Emidio Pacecca, Jye Tebble, Joel Hocking, Thomas Kempton and Aaron J. Coutts
should display measurement characteristics of validity (the ability of a test to measure what it is designed to measure), reliability (the consistency of results from a test), and sensitivity (the extent to which a test can detect changes beyond the typical error [TE] in results). 10 , 11 Reliability
Simon A. Feros, Warren B. Young and Brendan J. O’Brien
sensitivity in measurements of consistency (speed and accuracy). Knowing the reliability and sensitivity of all pace-bowling performance measures would allow researchers to more accurately quantify pace-bowling performance after short- and long-term interventions. A standardized test would be beneficial to
Greg Petrucci Jr., Patty Freedson, Brittany Masteller, Melanna Cox, John Staudenmayer and John Sirard
replacement for research-grade measurement devices, it is important to directly determine if the device can detect change in measures of activity behavior. Previous work has studied the sensitivity of research-grade accelerometers to detect change ( Lee, Clark, Winkler, Eakin, & Reeves, 2015 ; Montoye
Alyssa J. Wagner, Casey D. Erickson, Dayna K. Tierney, Megan N. Houston and Cailee E. Welch Bacon
Eating disorders in female athletes are a commonly underdiagnosed condition. Better screening tools for eating disorders in athletic females could help increase diagnosis and help athletes get the treatment they need.
Focused Clinical Question:
Should screening tools be used to detect eating disorders in female athletes?
Summary of Key Findings:
The literature was searched for studies that included information regarding the sensitivity and specificity of screening tools for eating disorders in female athletes. The search returned 5 possible articles related to the clinical question; 3 studies met the inclusion criteria (2 cross-sectional studies, 1 cohort study) and were included. All 3 studies reported sensitivity and specificity for the Athletic Milieu Direct Questionnaire version 2, the Brief Eating Disorder in Athletes Questionnaire version 2, and the Physiologic Screening Test to Detect Eating Disorders Among Female Athletes. All 3 studies found that the respective screening tool was able to accurately identify female athletes with eating disorders; however, the screening tools varied in sensitivity and specificity values.
Clinical Bottom Line:
There is strong evidence to support the use of screening tools to detect eating disorders in female athletes. Screening tools with higher sensitivity and specificity have demonstrated a successful outcome of determining athletes with eating disorders or at risk for developing an eating disorder.
Strength of Recommendation:
There is grade A evidence available to demonstrate that screening tools accurately detect female athletes at risk for eating disorders.
Justin W.Y. Lee, Ming-Jing Cai, Patrick S.H. Yung and Kai-Ming Chan
hamstring strength. The objectives of this study were to establish the test–retest reliability, validity, and sensitivity of a novel smartphone-based method designed for objective evaluation of hamstring strength among healthy male professional football players. Methods A cross-sectional study design was
Samuel Ryan, Thomas Kempton, Emidio Pacecca and Aaron J. Coutts
measurement characteristics of reliability and sensitivity of a standardized adductor strength assessment system for professional Australian footballers. This information will assist practitioners in interpreting changes in the adductor strength of players at major time points following professional
Lee N. Burkett, Jack Chisum, Jack Pierce and Kent Pomeroy
Twenty spinal injured wheelchair bound individuals were tested to peak VO2 on a wheelchair ergometer. Sixteen subjects were paraplegics (5 females, 11 males) and four were quadriplegic (2 females, 2 males). The level of injury ranged from C4-5 to L2-3. The mean age of the subjects was 29.9 years, with a mean weight of 63.66 kg. Prior to the peak VO2 and during the rest immediately after peak VO2, each subject was tested for the ability to discriminate touch over the skin of the thigh, leg, and foot. A chi square statistical technique was used to test for differences between pre- and postexercise sensitivity. The chi square was significant at the .003 level of significance. Because the increase in sensitivity was short, it was theorized that under peak exercise stress the body may recruit pathways that have been dormant, but not injured, explaining the increase in sensitivity.
Jose A. Rodríguez-Marroyo, Javier Medina-Carrillo, Juan García-López, Juan C. Morante, José G. Villa and Carl Foster
To analyze the concurrent and construct validity of a volleyball intermittent endurance test (VIET). The VIET’s test–retest reliability and sensitivity to assess seasonal changes was also studied.
During the preseason, 71 volleyball players of different competitive levels took part in this study. All performed the VIET and a graded treadmill test with gas-exchange measurement (GXT). Thirty-one of the players performed an additional VIET to analyze the test–retest reliability. To test the VIET’s sensitivity, 28 players repeated the VIET and GXT at the end of their season.
Significant (P < .001) relationships between VIET distance and maximal oxygen uptake (r = .74) and GXT maximal speed (r = .78) were observed. There were no significant differences between the VIET performance test and retest (1542.1 ± 338.1 vs 1567.1 ± 358.2 m). Significant (P < .001) relationships and intraclass correlation coefficient (ICC) were found (r = .95, ICC = .96) for VIET performance. VIET performance increased significantly (P < .001) with player performance level and was sensitive to fitness changes across the season (1458.8 ± 343.5 vs 1581.1 ± 334.0 m, P < .01).
The VIET may be considered a valid, reliable, and sensitive test to assess the aerobic endurance in volleyball players.
Tim J. Gabbett and Boris Georgieff
To develop a skill assessment for junior volleyball players and to evaluate the reliability, validity, and sensitivity of the test for detecting training-induced improvements in skill.
Thirty junior volleyball players (mean ± SD age, 15.5 ± 1.0 years) participated in this study. Subjects performed tests of spiking, setting, serving, and passing skills on 2 separate occasions to determine test–retest reliability of accuracy. Two expert coaches evaluated the players’ technique and reevaluated it 1 month after the initial evaluation to determine the intratester reliability for technique measurements. A third expert coach determined the intertester reliability for technique measurements. The validity of the test to discriminate players of different playing abilities was evaluated by testing junior national, state, and novice volleyball players. Finally, each player participated in an 8-week skill-based training program.
Accuracy measurements and intratester and intertester ratings of players’ technique proved to be highly reproducible (intraclass correlation coefficient, r, .85 to .98, range of typical error of measurement 0.2% to 10.0%). A progressive improvement in skill was observed with increases in playing level, while training-induced improvements were present in all skill tasks.
These results demonstrate that skill-based testing offers a reliable method of quantifying development and progress in junior volleyball players. In addition, the skill-testing battery was useful in successfully discriminating playing ability among junior volleyball players of varying levels, and it was sensitive to changes in skill with training. These fi ndings demonstrate that skill-based testing is useful for monitoring the development of junior volleyball players.