Martin A. Fees
James G. Hay
There have been few attempts to synthesize the knowledge gleaned from the study of cyclic human locomotion and, specifically, to determine whether there are general laws that describe or govern all such forms of locomotion. The purpose of this paper was to test the hypothesis that, when a human participant performs multiple trials of a given form of cyclic locomotion at a wide range of speeds (S) and without constraint on cycle rate (CR) or cycle length (CL), the relationships of CR vs. S and CL vs. S have the same basic characteristics as do those for any other form of cyclic locomotion. Data were gathered from published and unpublished sources. For each participant and form of locomotion, CR-vs.-S and CL-vs.-S relationships were plotted on a common scattergram with S on the abscissa and both CR and CL on the ordinate. Analysis of data collected on 49 participants and 12 forms of locomotion showed that, for every combination of participant and form of locomotion considered (excluding combinations involving simulated locomotion), the relationships of CR vs. S and CL vs. S had the same basic characteristics. These relationships were quadratic in form with CR-vs.-S concave upward and CL-vs.-S concave downward. The factor that made the greater contribution to increases in S was a function of S, with CL the primary factor at low S and CR the primary factor at high S. In short, the results obtained provided unequivocal support for the hypothesis of the study. The basic CR-vs.-S and CL-vs.-S relationships observed for forms of actual locomotion were also observed for some, but not all, of the forms of simulated locomotion examined.
Henrik Koblauch, Thomas Heilskov-Hansen, Tine Alkjær, Erik B. Simonsen and Marius Henriksen
It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment compression force increased during external foot rotation and the lateral knee joint compartment compression force increased during internal foot rotation. The increases in joint loads may be a result of increased knee flexion angles. Further, these data suggest that the frontal plane knee joint moment is not a valid surrogate measure for knee joint compression forces but rather indicates the medial-to-lateral load distribution.
Brandon C. Platt, Sue Falsone and Kenneth C. Lam,
the right inferior hemiscrotum and the patient was taken to recovery in stable condition. Comparative Outcomes The patient returned to competition following a return-to-play progression designed by the physician and athletic trainer (Table 2 ). After 13 days of rest, the patient completed a day of
Xavier D. Thompson and Brianna DiAntonio
The high rate of injury and re-injury, as well as the challenge of returning patients to activity, must all be considered postinjury. There is a dearth of research regarding ACL injuries and return to play in track and field athletes. This case report examines the return-to-play progression of a short
Emmanuel Jacobs, Ann Hallemans, Jan Gielen, Luc Van den Dries, Annouk Van Moorsel, Jonas Rutgeerts and Nathalie A. Roussel
values. The mean speed of progression (the speed with which the performer moves through space) was calculated by the product of stride length and stride frequency, based on the progression of the ankle marker. Statistical Analyses Statistical analysis was performed in IBM/SPSS (version 22 for Windows
Oladipo O. Eddo, Bryndan W. Lindsey, Shane V. Caswell, Matt Prebble and Nelson Cortes
investigate the acute changes in the biomechanical parameters of the nonmodified side in participants undergoing dose-specific medial knee thrust, lateral trunk lean, and toe-in foot progression gait modification. It was hypothesized that implementing these gait modification strategies would increase the
Dimitrios-Sokratis Komaris, Cheral Govind, Andrew Murphy, Alistair Ewen and Philip Riches
movement alterations is to unload the affected joint while keeping the pain experienced to a minimum. 13 – 15 Yet such asymmetric adaptations can lead to the progression of the disease, and even knee replacements in the contralateral joints in patients with end-stage osteoarthritis. 16 , 17 The
Sarah C. Moudy, Neale A. Tillin, Amy R. Sibley and Siobhán Strike
postulated to result from the inability of the prosthesis to generate the propulsion required to continue forward progression 1 or, in bilateral jump landings, from inadequate absorption of high forces through the prosthesis. 6 These interactions between the prosthetic and intact limb mechanics may explain
Rebecca J. Guthrie, Terry L. Grindstaff, Theodore Croy, Christopher D. Ingersoll and Susan A. Saliba
Individuals with low back pain (LBP) are thought to benefit from interventions that improve motor control of the lumbopelvic region. It is unknown if therapeutic exercise can acutely facilitate activation of lateral abdominal musculature.
To investigate the ability of 2 types of bridging-exercise progressions to facilitate lateral abdominal muscles during an abdominal drawing-in maneuver (ADIM) in individuals with LBP.
Randomized control trial.
University research laboratory.
51 adults (mean ± SD age 23.1 ± 6.0 y, height 173.6 ± 10.5 cm, mass 74.7 ± 14.5 kg, and 64.7% female) with LBP. All participants met 3 of 4 criteria for stabilization-classification LBP or at least 6 best-fit criteria for stabilization classification.
Participants were randomly assigned to either traditional-bridge progression or suspension-exercise-bridge progression, each with 4 levels of progressive difficulty. They performed 5 repetitions at each level and were progressed based on specific criteria.
Main Outcome Measures:
Muscle thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) was measured during an ADIM using ultrasound imaging preintervention and postintervention. A contraction ratio (contracted thickness:resting thickness) of the EO, IO, and TrA was used to quantify changes in muscle thickness.
There was not a significant increase in EO (F 1,47 = 0.44, P = .51) or IO (F 1,47 = .30, P = .59) contraction ratios after the exercise progression. There was a significant (F 1,47 = 4.05, P = .05) group-by-time interaction wherein the traditional-bridge progression (pre = 1.55 ± 0.22; post = 1.65 ± 0.21) resulted in greater (P = .03) TrA contraction ratio after exercise than the suspension-exercise-bridge progression (pre = 1.61 ± 0.31; post = 1.58 ± 0.28).
A single exercise progression did not acutely improve muscle thickness of the EO and IO. The magnitude of change in TrA muscle thickness after the traditional-bridging progression was less than the minimal detectable change, thus not clinically significant.