improving their movement quality and reduce subsequent injury risk. 3 Unfortunately, these attempts to evaluate and intervene to improve movement patterns have significant shortcomings as they fail to consider the role that kinetics, such as loading characteristics, play in the risk of primary or secondary
Search Results
The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing
Caroline Lisee, Tom Birchmeier, Arthur Yan, Brent Geers, Kaitlin O’Hagan, Callum Davis, and Christopher Kuenze
Kinetics and Stabilization of the Tuck Jump Assessment
Lucy S. Kember, Rhodri S. Lloyd, Gregory D. Myer, and Isabel S. Moore
sensitivity. Previous research has suggested that kinetics during rebounding tasks can be predictors of ACL injury. 7 , 8 Stiff landings with minimal knee flexion have been shown to produce large vertical ground reaction forces (Fz) and result in high knee joint loads and strain on the ACL, which may
Strides to Achieve a Stable Symmetry Index During Running
Shane P. Murphy, Zach B. Barrons, and Jeremy D. Smith
important to emphasize that not all variables reached a SMSI in the same number of strides, with some measures such as joint kinetics and joint angles requiring a greater number of strides (Table 1 ). This discretion between variables may partially be due to how variant the discrete measures are during
Intersession Variability of Knee Extension Kinetics Using a Strain Gauge Device With Differing Clinically Practical Physical Constraints
Christopher M. Juneau, Shelley N. Diewald, Jonathan Neville, John B. Cronin, and Dustin J. Oranchuk
the biomechanics and physiology of the musculotendinous 8 and nervous systems. 9 Assessing kinetics requires varying affordability and practicality technologies, contributing to the relative nonuse of rapid force metrics in physical medicine. 2 Gold standard equipment (ie
Joint Torques and Patellofemoral Force During Single-Leg Assisted and Unassisted Cycling
Rodrigo R. Bini, Tiago C. Jacques, and Marco A. Vaz
Context:
Unassisted single-leg cycling should be replaced by assisted single-leg cycling, given that this last approach has potential to mimic joint kinetics and kinematics from double-leg cycling. However, there is need to test if assisting devices during pedaling effectively replicate joint forces and torque from double-leg cycling.
Objectives:
To compare double-leg, single-leg assisted, and unassisted cycling in terms of lower-limb kinetics and kinematics.
Design:
Cross-sectional crossover.
Setting:
Laboratory.
Participants:
14 healthy nonathletes.
Interventions:
Two double-leg cycling trials (240 ± 23 W) and 2 single-leg trials (120 ± 11 W) at 90 rpm were performed for 2 min using a bicycle attached to a cycle trainer. Measurements of pedal force and joint kinematics of participants’ right lower limb were performed during double- and single-leg trials. For the single-leg assisted trial, a custom-made adaptor was used to attach 10 kg of weight to the contralateral crank.
Main Outcome Measures:
Peak hip, knee, and ankle torques (flexors and extensors) along with knee-flexion angle and peak patellofemoral compressive force.
Results:
Reduced peak hip-extensor torque (10%) and increased peak knee-flexor torque (157%) were observed at the single-leg assisted cycling compared with the double-leg cycling. No differences were found for peak patellofemoral compressive force or knee-flexion angle comparing double-leg with single-leg assisted cycling. However, single-leg unassisted cycling resulted in larger peak patellofemoral compressive force (28%) and lower knee-flexion angle (3%) than double-leg cycling.
Conclusions:
These results suggest that although single-leg assisted cycling differs for joint torques, it replicates knee loads from double-leg cycling.
Tibiofemoral Joint Kinetics during Squatting with Increasing External Load
Sonia Sahli, Haithem Rebai, Mohamed Habib Elleuch, Zouheir Tabka, and Georges Poumarat
Context:
There is limited information about the effects of increasing load while squatting
Objective:
To quantify tibiofemoral joint kinetics during squatting with variable loads.
Setting:
Research laboratory.
Participants:
20 male students.
Intervention:
Tibiofemoral joint kinetics and electromyographic (EMG) activity of four involved muscles were determined by recording the half squat with variable external loads.
Main Outcome Measures:
Tibiofemoral joint force and external moment components and EMG activity of four involved muscles.
Results:
Throughout the exercise, a posterior direction for the antero-posterior shear force and a net extension for the external moment were observed. They increased with knee flexion reaching peak force of 29% of the subject body weight (BW) and moment of 88Nm (without external load). All force and moment components and muscle activities increased as the external load increased.
Conclusion:
These findings suggest that half squat may be safe to use for quadriceps strengthening with very low potential loading on the anterior cruciate ligament (ACL). Our data can help clinicians choose the appropriate external load.
Patellofemoral Joint Loading During Single-Leg Hopping Exercises
Abbigail Ristow, Matthew Besch, Drew Rutherford, and Thomas W. Kernozek
kinematics and kinetics during single-leg hopping have been examined between those with and without PFP. 25 However, kinetic and kinematic differences have not been explored with a different hopping cadence. The purpose of this study was to observe if there was a difference in PFJ loading variables between
Erratum. The Single Hop for Distance Test: Reviewing the Methodology to Measure Maximum and Repeated Performance
Human Kinetics, Inc.
Temporal Values and Plantar Pressures during Normal Walking and Racewalking in a Group of Racewalkers
M. Adoración Villarroya, José Antonio Casajús, and José María Pérez
Objectives:
To compare temporal and pressure values between racewalking and normal walking (freely selected speed) and evaluate the impact of racewalking on normal walking.
Design and Participants:
Temporal and plantar-pressure values were recorded (xPression system) during normal walking and racewalking in 8 high-level racewalkers. The Wilcoxon test was used for comparisons.
Measurements:
Duration of walking and racewalking cycle phases (seconds and percentage of the cycle), peak and average pressures under the hind foot and metatarsal heads, and pressure distribution (%) among metatarsal heads.
Results and Conclusions:
Normal walking: temporal parameters similar to those described in normal gait; peak pressures higher than those described in nonracewalkers with displacement toward lateral forefoot. Racewalking: shorter cycles (important decrease of midstance phase); higher peak pressures than during normal walking in the hind foot and 4th and 5th metatarsal heads; average pressures similar to normal walking in hind foot and lower in forefoot; pressure displacement toward lateral forefoot greater than in normal walking.
Gluteus Medius Activity during Isometric Closed-Chain Hip Rotation
Randy J. Schmitz, Bryan L. Riemann, and Timothy Thompson
Objective:
To determine whether gluteus medius (GM) activity increases in response to isometric closed-chain external hip rotation.
Design:
Subjects performed single-leg stances in 3 different conditions: 0° knee flexion, 0° hip flexion (C1); 0° knee flexion, 20° hip flexion (C2); and knee flexed 20–30°, 20° hip flexion (C3). Posteriorly directed forces of 8.9 N (F1), 17.8 N (F2), and 26.7 N (F3) were applied at the lateral pelvis of the nonstance side during each condition.
Subjects:
20 college students.
Measurements:
Surface EMG RMS amplitude from the GM and kinematic data from the trunk, hip, and knee.
Results:
Statistical analyses revealed a significant Condition 3 Force interaction and significant increases of EMG activity from C1F1 and C1F2 to C1F3 and from C3F1 to C3F2 and C3F3. F2 and F3 of C2 were significantly less than F2 and F3 of both C1 and C3.
Conclusions:
GM activity increases in response to isometric, closed-chain, external hip-rotation forces, and forward movement of the upper body with respect to the base of support decreases GM activity.
