Search Results

You are looking at 61 - 70 of 342 items for :

  • Athletic Training, Therapy, and Rehabilitation x
Clear All
Restricted access

Steven Malvasi, Brian Gloyeske, Matthew Johnson and Timothy Miller

Background:

Injury to the anterior cruciate ligament (ACL) is one of the most common orthopedic injuries in the United States, while injury to the patellar tendon (PT) is less common. A combined rupture to the ACL and PT is consequentially uncommon and increases the difficulty of a correct initial diagnosis. The purpose of this paper is to critically appraise the current peer-reviewed literature regarding multi-ligamentous knee injuries (MLKI) in sport.

Methods:

A systematic review was undertaken to identify all relevant peer-reviewed articles regarding MLKI from March 1980 to January 2015. All articles pertaining to simultaneous rupture of the ACL and PT were included for review.

Results:

A total of 27 cases presented in 15 articles were used. Findings suggest that the combination of a palpable gap over the PT, a positive Lachman test, inability to complete terminal knee extension, and a superior position of the patella are clinical examination markers for a possible MLKI involving the ACL and PT.

Conclusion:

Simultaneous rupture to the ACL and PT is incredibly rare within the sport population, making diagnosis and treatment of such injury challenging. A thorough examination of the extensor mechanism of the knee is important in making the proper diagnosis.

Restricted access

Ryota Akagi, Soichiro Iwanuma, Satoru Hashizume, Hiroaki Kanehisa, Toshimasa Yanai and Yasuo Kawakami

The purpose of this study was to investigate how the contraction-induced increase in distal biceps brachii tendon moment arm is related to that in elbow flexor muscle thickness, with a specific emphasis on the influence of the site-related differences in muscle thickness. The moment arm and muscle thickness were determined from sagittal and cross-sectional images, respectively, of the right arm obtained by magnetic resonance imaging of nine young men. The muscle thickness was measured at levels from the reference site (60% of the upper arm length from the acromial process of the scapula to the lateral epicondyle of the humerus) to 60 mm distal to it (every 10 mm; 7 measurement sites). At 80° of elbow flexion, the moment arm and muscle thickness were determined at rest and during 60% of maximal voluntary contraction (60%MVC) of isometric elbow flexion. Only the relative change from rest to 60%MVC in muscle thickness at the level 60 mm distal to the reference site correlated significantly with that of the moment arm. This result indicates that the contraction-induced increase in distal biceps brachii tendon moment arm is related to that in elbow flexor muscle thickness near the corresponding muscle-tendon junction.

Restricted access

Masatoshi Nakamura, Tome Ikezoe, Takahiro Tokugawa and Noriaki Ichihashi

Context:

Hold–relax stretching (HRS) and static stretching (SS) are commonly used to increase joint range of motion (ROM) and decrease muscle stiffness. However, whether there are differences between acute effects of HRS and SS on end ROM, passive torque, and muscle stiffness is unclear. In addition, any differences between the mechanisms by which HRS and SS lead to an increase in end ROM are unclear.

Objective:

To compare the acute effects of HRS and SS on the passive properties of the gastrocnemius muscle–tendon unit (MTU), end ROM, passive torque, and muscle stiffness in vivo and to investigate the factors involved in increasing end ROM.

Design:

Crossover experimental design.

Participants:

30 healthy men (21.7 ± 1.2 y) with no history of neuromuscular disease or musculoskeletal injury involving the lower limbs.

Intervention:

Both HRS and SS of 30 s were repeated 4 times, lasting a total of 2 min.

Main Outcome Measures:

End ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion using a dynamometer and ultrasonography before and immediately after HRS and SS.

Results:

The results showed that end ROM and passive torque at end ROM significantly increased immediately after both HRS and SS, whereas muscle stiffness significantly decreased. In addition, the percentage change in passive torque at end ROM on use of the HRS technique was significantly higher than that after use of the SS technique. However, the percentage change in muscle stiffness after SS was significantly higher than that with HRS.

Conclusion:

These results suggest that both HRS and SS can effectively decrease muscle stiffness of the gastrocnemius MTU and that HRS induces a change in the passive torque at end ROM—ie, sensory perception—rather than changing muscle stiffness.

Restricted access

Kevin M. Cross

Restricted access

R. McNeill Alexander

Restricted access

Dale J. Butterwick

Restricted access

Thomas S. Buchanan, David G. Lloyd, Kurt Manal and Thor F. Besier

This paper provides an overview of forward dynamic neuromusculoskeletal modeling. The aim of such models is to estimate or predict muscle forces, joint moments, and/or joint kinematics from neural signals. This is a four-step process. In the first step, muscle activation dynamics govern the transformation from the neural signal to a measure of muscle activation—a time varying parameter between 0 and 1. In the second step, muscle contraction dynamics characterize how muscle activations are transformed into muscle forces. The third step requires a model of the musculoskeletal geometry to transform muscle forces to joint moments. Finally, the equations of motion allow joint moments to be transformed into joint movements. Each step involves complex nonlinear relationships. The focus of this paper is on the details involved in the first two steps, since these are the most challenging to the biomechanician. The global process is then explained through applications to the study of predicting isometric elbow moments and dynamic knee kinetics.

Restricted access

Sarah Ritchie

Column-editor : Jeff G. Konin

Restricted access

Rohit Shah and Amanda Sinclair

Edited by Tricia Hubbard