This study was concerned with the measurement of performance variables from competitors in the men's long jump final of the World Student Games held in Sheffield, England, in July 1991. Several performances of 10 finalists were recorded on cine film at 100 Hz. Resulting sagittal plane kinematic data were obtained for the last stride, touchdown, and takeoff for a total of 27 jumps. It was confirmed that takeoff velocity was a function of touchdown velocity, and that there was an increase in vertical velocity at the expense of a reduction of horizontal velocity. It was concluded that there was evidence for mechanisms which may be termed mechanical, biomechanical, and muscular. The former relates to the generation of vertical velocity by the body pivoting over the base of support during the compression phase, and a lifting of the arms and free leg during the lift phase; the second is the elastic reutilization of energy; and the third is the contribution by concentric muscular contraction.
Adrian Lees, Philip Graham-Smith and Neil Fowler
Emma Sconce, Paul Jones, Ellena Turner, Paul Comfort and Philip Graham-Smith
Hamstring injury-risk assessment has primarily been investigated using isokinetic dynamometry. However, practical issues such as cost and availability limit the widespread application of isokinetics for injury-risk assessment; thus, field-based alternatives for assessing eccentric hamstring strength are needed.
The aim of this study was to investigate the validity of the angle achieved during Nordic hamstring lowers (break-point angle) as a field-based test for eccentric hamstring strength.
Sixteen male (n = 7) and female (n = 9) soccer players (mean ± SD age 24 ± 6 y, height 1.77 ± 0.12 m, and body mass 68.5 ± 16.5 kg) acted as subjects for the study.
Main Outcome Measures:
The authors explored relationships between the Nordic break-point angle (the point at which the subject can no longer resist the increasing gravitational moment during a Nordic hamstring lower) measured from video and isokinetic peak torque and angle of peak torque of right- and left-knee flexors.
The results revealed a meaningful relationship between eccentric knee-flexor peak torque (average of right and left limbs) and the Nordic break-point angle (r = −.808, r 2 = 65%, P < .00001). However, there was a weak relationship observed (r = .480, r 2 = 23%, P = .06) between break-point angle and the angle of peak torque (average of right and left limbs).
The results suggest that the break-point angle achieved during Nordic hamstring lowers could be used as a field-based assessment of eccentric hamstring strength.