measurement of normalized eccentric peak torque (NEPT). 14 Rare scientific studies in the literature explain the mechanical and anatomical adaptation of external shoulder joint musculature to any faulty mechanics at the elbow and wrist joints. 14 On the other hand, there are several compensatory strategies
Bassam A. Nabil, Mariam A. Ameer, Azza M. Abdelmohsen, Abeer F. Hanafy, Ahmed S. Yamani, Naglaa M. Elhafez and Salam M. Elhafez
Il-young Yu, Dong-kyu Lee, Myoung-Joo Kang and Jae-seop Oh
sample size (ver. 3.1.2; Franz Faul, University of Kiel, Kiel, Germany) in a pilot study of 5 subjects. A SD of isokinetic ER peak torque (PT) difference (5.4 Nm) was used. A priori calculation of the sample size was performed with a power of 0.80, alpha level of .05, and effect size of 0.97. The result
Samantha J. Wilson, Bryan Christensen, Kara Gange, Christopher Todden, Harlene Hatterman-Valenti and Jay M. Albrecht
Acute static stretching has been shown to decrease muscle performance 1 ; however, chronic stretching has been shown to improve several athletic performance variables over time including 1-repetition maximum (1RM), 2 flexibility, gait economy, 3 running speed, 4 peak torque, 5 and vertical jump
Terry J. Housh, Glen O. Johnson, Dona J. Housh, Jeffrey R. Stout, Joseph P. Weir, Loree L. Weir and Joan M. Eckerson
The purpose of the present study was to examine age-related changes in isokinetic leg flexion and extension peak torque (PT), PT/body weight (PT/BW), and PT/fat-free weight (PT/FFW) in young wrestlers. Male wrestlers (N = 108; age M ± SD = 11.3 ± 1.5 years) volunteered to be measured for peak torque at 30, 180, and 300° · s−1. In addition, underwater weighing was performed to determine body composition characteristics. The sample was divided into six age groups (8.1−8.9, n = 10; 9.0−9.9, n= 11; 10.0−10.9, n = 25; 11.0−11.9, n = 22; 12.0−12.9, n = 28; 13.0−13.9, n = 12), and repeated measures ANOVAs with Tukey post hoc comparisons showed increases across age for PT, PT/BW, and PT/FFW. The results of this study indicated that there were age-related increases in peak torque that could not be accounted for by changes in BW or FFW. It is possible that either an increase in muscle mass per unit of FFW, neural maturation, or both, contributes to the increase in strength across age in young male athletes.
Mary Hellen Morcelli, Dain Patrick LaRoche, Luciano Fernandes Crozara, Nise Ribeiro Marques, Camilla Zamfolini Hallal, Mauro Gonçalves and Marcelo Tavella Navega
torque development thresholds predictive of functional gait speeds for each joint action. Until now, no study has simultaneously compared the strengths of the 3 primary lower limb joints and their relation with gait speed in older adults. Therefore, this study aims to test the ability of peak torque and
Lasse Ishøi, Per Aagaard, Mathias F. Nielsen, Kasper B. Thornton, Kasper K. Krommes, Per Hölmich and Kristian Thorborg
hamstring strength and rate of torque parameters (independent variables) and sprint performance parameters (dependent variables) are presented in Table 1 . Table 1 Overview of Independent and Dependent Variables Mean (SD), N = 30 Independent variables Peak torque, N·m/kg 2.20 (0.33) 0–100 ms RTD, N
Terry J. Housh, Jeffrey R. Stout, Dona J. Housh and Glen O. Johnson
The purpose of this investigation was to examine the covariate influence of estimated muscle mass on age-related increases in isokinetic peak torque for flexion and extension of the forearm and leg in high school wrestlers. One hundred thirteen high school wrestlers volunteered to be measured for strength at 30, 180, and 300°·s−1. Underwater weighing was performed to determine body composition characteristics, and the anthropometric equation of Martin et al. (10) was used to estimate total skeletal muscle mass (MM). There were significant (p < .05) relationships (r = .19 to .37) for age versus peak torque covaried independently for fat-free weight (FFW) and MM for forearm flexion at 30, 180, and 300°·s−1; forearm extension at 180 and 300°·s−1; and leg extension at 30, 180 and 300°·s−1. The results of this study indicated that there was no increase across age in MM per unit of FFW, and the age-related increases in peak torque in high school wrestlers could not be fully accounted for by changes in MM.
Athanasios Zakas, George Doganis, Christos Galazoulas and Efstratios Vamvakoudis
Although athletes routinely perform warm-up and stretching exercises, it has been suggested that prolonged stretching immediately before an activity might negatively affect the force production. Sixteen male pubescent soccer players participated in the study to examine whether a routine duration of acute static stretching is responsible for losses in isokinetic peak torque production. All participants performed two static stretching protocols in nonconsecutive training sessions. The first stretching protocol was performed three times for 15 s (volume 45) and the second 20 times for 15 s (volume 300). Range of motion (ROM) was determined during knee flexion with the use of a goniometer. The peak torque of the dominant leg extensors was measured on a Cybex NORM dynamometer at various angular velocities. The statistical analysis showed that peak torque did not change following the static stretching for 45 s in all angular velocities, while it decreased (p < .001) in all angular velocities following the static stretching for 5 min. The findings suggest that strength decreases after static stretching exercises may be the result of the performed stretching duration.
Laura A. Frey-Law, Andrea Laake, Keith G. Avin, Jesse Heitsman, Tim Marler and Karim Abdel-Malek
Recognizing the importance of both the torque-angle and torque-velocity relations, three-dimensional (3D) human strength capabilities (i.e., peak torque as a function of both joint angle and movement velocity) have been increasingly reported. It is not clear, however, the degree to which these surfaces vary between joints, particularly between joints with similar biomechanical configurations. Thus, our goal was to compare 3D strength surfaces between the muscles about the elbow and knee hinge joints in men and women. Peak isometric and isokinetic strength was assessed in 54 participants (30 men) using the Biodex System 3 isokinetic dynamometer. Normalized peak torque surfaces varied significantly between flexion and extension (within each joint) and between joints; however, the normalized 3D torque surfaces did not differ between men and women. These findings suggest the underlying joint biomechanics are the primary influences on these strength surface profiles. Therefore, in applications such as digital human modeling, torque-velocity-angle relationships for each joint and torque direction must be uniquely represented to most accurately estimate human strength capability.
John P. Miller, Kerriann Catlaw and Robert Confessore
The purpose of this study was to examine the effect of ankle position on the electromyographic (EMG) activity, peak torque, and peak knee flexion to extension torque ratio during isokinetic testing of the knee. Twelve healthy female athletes performed six maximal knee extension and flexion repetitions with their dominant legs at 60 and 180°/s with the ankle in a plantar flexed position and again in a dorsiflexed position. Root mean square EMG (rmsEMG) activity was determined by placing bipolar surface electrodes on the quadriceps and the hamstrings. Ankle position had no effect on the rmsEMG activity of the quadriceps or the hamstrings at either 60 or 180°/s. Significant differences were noted for peak flexor torque at 607s (p < .001) and 180°/s (p <.01) and for peak torque flexor/extensor ratio (p < .01), with higher values observed with ankle dorsiflexion. This suggests that ankle position affects knee flexor torque and flexor/extensor ratio but not hamstring activity during isokinetic testing of the knee.