Landing Phase Of Jumps Research Articles

Diagnosis, management and long‐term outcome of four cases of carpal flexor retinaculum desmopathy

SummaryFour cases of flexor retinaculum desmopathy following an accident during the landing phase of jumping and their outcomes are discussed, and an overview of the subjects is provided. The four horses presented with a sudden onset of severe lameness during landing after jumping, which markedly decreased in the first few days. In all cases, the painful area was not localisable on the first day; however, marked swelling was observed on the second day and in all cases, the injury to the carpal flexor retinaculum was visible on ultrasound. The horses were sound in a straight line at 9 (Case 1), 4 (Case 2) and 2 (Case 3) weeks after the injury. Case 4 was not presented until 8 weeks after the incident. During subsequent examination, Case 4 was found to be sound, although it had not returned to training. The owner reported the lameness ended 4 weeks after the incident. All the horses successfully returned to their former competition levels and did not show any problems related to the carpal flexor retinaculum. However, there were significant differences in the regeneration times among the cases, ranging from 5 to 21 months.

Biomechanical variations in children who are overweight and obese during high-impact activities: A systematic review and meta-analysis.

Youth who are obese or overweight demonstrate evidence of poor lower extremity joint health and alterations in gait characteristics compared with youth who are healthy weight. However, there is no consensus if altered movement patterns are still present during high-impact activities. The purpose of this review was to determine if spatiotemporal and kinematic and kinetic variables during high-impact activities were significantly different between youth who are overweight and obese compared with youth who are healthy weight. An electronic search of five databases was conducted, and a meta-analysis and qualitative evidence synthesis was performed to determine the level of evidence, analyzing three tasks: running, jumping, and hopping. The findings of this review include the following: (1) overweight/obese (OW/OB) had higher stance phase time during running, (2) OW/OB had decreased hip flexion angles during running and stationary running, (3) OW/OB had decreased knee flexion angles during landing phase of jumping and hopping, and (4) OW/OB had increased hip abduction moments during running and jumping. These altered kinematic and kinetic variables at the hip and knee may result in mechanical inefficiency with high-impact activities, as well as potentially increased risk of joint degradation and poor joint health into adulthood.

Effects of different types of jump impact on trabecular bone mass and microarchitecture in growing rats.

Substantial evidence from animal studies indicates that jumping increases bone mass and strength. However, most studies have focused on the take-off, rather than the landing phase of jumps. Thus, we compared the effects of landing and upward jump impact on trabecular bone mass and microarchitecture. Male Wistar rats aged 10 weeks were randomly assigned to the following groups: sedentary control (CON), 40-cm upward jumps (40UJ); 40-cm drop jumps (40DJ); and 60-cm drop jumps (60DJ) (n = 10 each). The upward jump protocol comprised 10 upward jumps/day, 5 days/week for 8 weeks to a height of 40 cm. The drop jump protocol comprised dropping rats from a height of 40 or 60 cm at the same frequency and time period as the 40UJ group. Trabecular bone mass, architecture, and mineralization at the distal femoral metaphysis were evaluated using microcomputed tomography. Ground reaction force (GRF) was measured using a force platform. Bone mass was significantly higher in the 40UJ group compared with the DJ groups (+49.1% and +28.3%, respectively), although peak GRF (−57.8% and −122.7%, respectively) and unit time force (−21.6% and −36.2%, respectively) were significantly lower in the 40UJ group. These results showed that trabecular bone mass in growing rats is increased more effectively by the take-off than by the landing phases of jumps and suggest that mechanical stress accompanied by muscle contraction would be more important than GRF as an osteogenic stimulus. However, the relevance of these findings to human bone physiology is unclear and requires further study.

Timing of Lower Extremity Frontal Plane Motion Differs Between Female and Male Athletes During a Landing Task

Background: Female athletes are at a greater risk for noncontact anterior cruciate ligament injuries than male athletes. Gender differences in frontal plane kinematics (hip adduction, knee valgus, and ankle eversion) and temporal relationships that make up the components of dynamic knee valgus may explain this discrepancy. Hypothesis: The authors hypothesized that women would reach peak frontal plane kinematic values earlier during landing compared with their male counterparts. Study Design: Controlled laboratory study. Methods: Hip, knee, and ankle 3-dimensional kinematics were measured using high-speed motion capture in 10 National Collegiate Athletic Association Division I female athletes and 10 male practice squad athletes during a drop-jump landing. Independent t tests were used to analyze each dependent variable to identify differences between genders. Results: Maximum hip adduction, knee valgus, and ankle eversion occurred earlier in women than in men (mean differences 33.7% of stance [95% CI, 20.2%-47.2%], 41.7% [95% CI, 31.5%-51.6%], 16.5% of stance [95% CI, 7.3%-25.6%], respectively). Maximum hip adduction and knee valgus occurred before maximum knee flexion in women and after in men (mean differences 0.11 seconds [95% CI, 0.05-0.18 seconds], 0.19 seconds [95% CI, 0.13-0.25 seconds], respectively). Maximum ankle eversion occurred earlier in women than in men (mean difference 0.06 seconds [95% CI, 0.01-0.11 seconds]). There was a significant difference between genders for angular velocity of knee valgus (mean difference = 25.53 deg/sec [95% CI, 8.30-42.77 deg/sec]). Conclusion: Frontal plane kinematic temporal relationships at the hip, knee, and ankle differ between genders. The components of dynamic knee valgus peak during the deceleration phase in women and during the acceleration phase in men during a drop-jump landing. These data suggest that men and women employ a completely different kinematic landing/jumping strategy and that women land and collapse very rapidly into valgus compared with their male counterparts. Clinical Relevance: The differences in timing of the components of dynamic knee valgus between women and men may contribute to the increased risk of noncontact anterior cruciate ligament injuries in female athletes. There may be implications for neuromuscular reeducation training in those at risk for anterior cruciate ligament injury so the components of dynamic valgus occur later in the landing phase of jumping.

Força de reação do solo como subsídio para prescrição de exercícios aquáticos: estudo de caso

OBJETIVO: Comparar a componente vertical da força de reação do solo nos exercícios de caminhada, corrida com deslocamento, corrida estacionária e salto vertical, realizados em ambiente aquático em diferentes níveis de imersão. MÉTODO: Participou deste estudo de caso um sujeito do sexo masculino (27 anos, 1,80 m e 84,3 kg). Utilizou-se para a coleta de dados uma plataforma subaquática de força posicionada no fundo de uma piscina térmica. O sujeito realizou 30 tentativas válidas de cada exercício, imerso nos níveis do processo xifoide e do quadril. Os dados foram analisados com a utilização da estatística descritiva, teste "t" de Student para amostras pareadas e ANOVA, para medidas repetidas (p < 0,05). RESULTADOS: Os valores máximos da força para os níveis do processo xifoide e do quadril (em % do peso corporal do sujeito) foram de, respectivamente: 39% e 48% para a caminhada; 138% e 156% para a corrida com deslocamento; 139% e 202% para a corrida estacionária; 194% e 195% para a propulsão no salto; e 222% e 387%, para a aterrissagem no salto. CONCLUSÃO: Ao variar o tipo de exercício podemos realizar um aumento de carga gradual, desde a caminhada no nível do processo xifoide até o salto no nível do quadril. Para tanto, deve ser analisado o objetivo do trabalho a ser realizado para a escolha do exercício correto, com o aumento da carga sendo realizado não somente pela diminuição do nível de imersão, como também pelo tipo e pela velocidade/cadência do exercício executado.

Preliminary investigation of maximal fetlock extension during jump landing phase on two arena surfaces; two dimensional motion analysis

Surface type has a recognised effect on the biomechanics of a horse, yet suitability of surfaces to discipline has not been fully substantiated. Ideal exercise surface conditions should be a balance of energy absorption to minimise concussion and energy return to aid performance (Barrey et al., 1999) and these conditions vary according to type of work. Greater force on a particular limb will increase the probability of injury, especially in sports that are repetitive in nature, such as show jumping. It is well known that high impact forces occur during the landing phase of jumping (Meershoek et al., 2001); investigation of this phase is therefore integral to understanding the effect that surface has on horses that jump. Maximal fetlock extension may be useful as an indicator of magnitude of ground reaction forces (Clayton, 1997). This means that in-field studies can be used to measure maximal fetlock extension as a guide to forces placed on the limb.