Effects of added trunk load and corresponding trunk position adaptations on lower extremity biomechanics during drop-landings. J Biomech
Department of Health Education and Promotion, East Carolina University, 249 Ward Sports Medicine Building, Greenville, NC 27858, USA. Journal of Biomechanics
(Impact Factor: 2.75).
02/2008; 41(1):180-5. DOI: 10.1016/j.jbiomech.2007.06.027
Although both trunk mass and trunk position have the potential to affect lower extremity biomechanics during landing, these effects are not well understood. Our overall hypothesis stated that both trunk mass and trunk position affect lower extremity biomechanics in landing. Thus, our purpose was to determine the effects of an added trunk load and kinematic trunk adaptation groups on lower extremity joint kinematics, kinetics, and energetics during drop-landings. Twenty-one recreationally active subjects were instrumented for biomechanical analysis. Subjects performed two sets of eight double-limb landings with and without 10% body weight added to the trunk. On lower extremity dependent variables, 2(condition: no load, trunk load)x2(group: trunk extensors vs. trunk flexors) ANOVAs were performed. Condition by group interactions at the hip showed differing responses to the added trunk load between groups where the trunk extensor group decreased hip extensor efforts ( downward decrease 11-18%) while the trunk flexor group increased hip extensor efforts ( upward increase 14-19%). The trunk load increased biomechanical demands at the knee and ankle regardless of trunk adaptation group. However, the percent increases in angular impulses and energy absorption in the trunk extensor group were 14-28% while increases in the trunk flexor group were 4-9%. Given the 10% body weight added to the trunk, the 14-28% increases at the knee and ankle in the trunk extensor group were likely due to the reduced hip extensor efforts during landing. Overall these findings support our overall hypothesis that both trunk mass and trunk position affect lower extremity biomechanics during vertically oriented landing tasks.
Available from: Laurent Ballaz
- "For instance, large force plates are easier to hit while walking, which reduces the time needed to gather the required valid trials. They are also more versatile as they can be used for large human movements such as manual materials handling  or for fast human movement such as running and jumping . However, one important limitation of large force plates is their incapacity in dissociating the forces generated by both feet individually when they hit the platform simultaneously. "
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A ground reaction force decomposition algorithm based on large force platform measurements has recently been developed to analyze ground reaction forces under each foot during the double support phase of gait. However, its accuracy for the measurement of the spatiotemporal gait parameters remains to be established.
The aim of the present study was to establish the agreement between the spatiotemporal gait parameters obtained using (1) a walkway (composed of six large force platforms) and the newly developed algorithm, and (2) an optoelectronic motion capture system.
Twenty healthy children and adolescents (age range: 6–17 years) and 19 healthy adults (age range: 19–51 years) participated in this study. They were asked to walk at their preferred speed and at a speed that was faster than the preferred one. Each participant performed three blocks of three trials in each of the two walking speed conditions.
The spatiotemporal gait parameters measured with the algorithm did not differ by more than 2.5% from those obtained with the motion capture system. The limits of agreement represented between 3% and 8% of the average spatiotemporal gait parameters. Repeatability of the algorithm was slightly higher than that of the motion capture system as the coefficient of variations ranged from 2.5% to 6%, and from 1.5% to 3.5% for the algorithm and the motion capture system, respectively.
The proposed algorithm provides valid and repeatable spatiotemporal gait parameter measurements and offers a promising tool for clinical gait analysis. Further studies are warranted to test the algorithm in people with impaired gait.
Available from: Javier Alonso-Álvarez
- "aumento de la cifosis dorsal) (Granacher et al., 2013) y esto puede que provoque cierta inestabilidad. De hecho, parece que la posición del tronco afecta de forma significativa a las fuerzas musculares de las piernas, especialmente en los isquiosurales, los cuales tienen un papel importante en el equilibrio y la estabilización del tronco (Kulas et al., 2008). Asimismo, la edad también puede que afecte negativamente a este control neuromuscular del tronco. "
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DESCRIPTION: Los problemas en el control del equilibrio corporal incrementan de manera importante la probabilidad de caídas en personas mayores. Varios autores sugieren que una adecuada capacidad de estabilización del tronco, así como altos niveles de fuerza de su musculatura podrían incrementar el equilibrio corporal, lo cual podría ser beneficioso para disminuir el riesgo de caídas en el adulto mayor. Sin embargo, existe una carencia de evidencias científicas que permitan establecer una relación clara entre la estabilidad y fuerza de tronco y el equilibrio corporal en personas mayores. El objetivo de nuestro estudio fue describir, por un lado, la posible relación entre la estabilidad de tronco en sedestación y la fuerza muscular del tronco sobre el rendimiento en pruebas de equilibrio corporal general y, por otro lado, analizar el efecto de la edad sobre la estabilidad y fuerza de tronco, así como sobre el equilibrio corporal general y sobre la relación que existe entre estas variables. En el estudio participaron 22 mujeres, 11 de ellas de entre 30 y 40 años y 10 de más de 60 años. Todas ellas realizaban actividad física al menos dos días a la semana. Para valorar la estabilidad del tronco se analizó su control postural mediante el paradigma del asiento inestable. Para valorar el equilibrio corporal se analizó el rendimiento en una prueba realizada sobre una plataforma de fuerzas. Para valorar la fuerza muscular se realizó un test de flexión y extensión isométrica del tronco en un dinamómetro isocinético.
Available from: PubMed Central
- "Blackburn and
Padua demonstrated that increased trunk extension upon landing increased the ground reaction
force and the quadriceps forces29). Similarly, Kulas et al. reported that increased trunk extension upon landing caused an
increase in quadriceps forces and a decrease in hamstring forces30). Increased quadriceps forces lead to anterior tibial
displacement, increasing the load on the ACL28, 31). Increased trunk extension is associated
with a decrease in the angle of hip joint flexion32). "
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ABSTRACT: [Purpose] Increased femoral anteversion may occur with hip internal rotation and valgus knee alignment upon landing and is considered a risk factor for anterior cruciate ligament injury. We examined the relationship between femoral anteversion and joint motion and muscle activity of the lower extremity in terms of the risk factors for anterior cruciate ligament injury. [Subjects] Sixteen healthy females were divided on the basis of femoral anteversion into low and high groups. [Methods] Femoral anteversion was assessed using Craig's test. We performed kinematic analysis and measured the electromyography activity of the lower extremity upon left single-leg landing. [Results] The high group had a significantly lower hip flexion angle and higher knee flexion and valgus angles than the low group. The rectus femoris showed significantly greater electromyography activities in the high group than in the low group. [Conclusion] These results suggest that increased femoral anteversion results in lower hip flexion angle, higher knee valgus alignment, and greater rectus femoris muscle activity, leading to anterior tibial displacement upon single-leg landing. Increased femoral anteversion may be a potential risk factor for anterior cruciate ligament injury.
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