Superficial digital flexor tendon lesions in racehorses as a sequela to muscle fatigue: A preliminary study

Abstract

Future research investigating distal limb system function as a whole should help refine clinical diagnostic procedures and exercise training approaches that will lead to more effective prevention and treatment of digital flexor tendon injuries in equine athletes.

Contractile properties of muscle fibers from the deep and superficial digital flexors of horses

“…In the distal forelimb of the horse, the DDF and SDF muscles share a similar mechanical advantage about the metacarpophalangeal joint (fetlock); however, muscle architecture of each muscle-tendon unit differs greatly, as do their functional roles in locomotion. The comparatively fast contracting DDF muscle (short compartment, humeral head), with its long fibers in a unipennate arrangement (20,54), shortens to generate modest amounts of mechanical work during locomotion, thus contributing to flexion of the digit late in the swing phase (9,10). In vivo performance of the DDF is consistent with a muscle composed of long and predominantly fast MHC-2A isoform fibers.…”

“…In contrast to the DDF, during locomotion the short multipennate fibers of the SDF (8,20,54) undergo isometric and lengthening (eccentric) contraction, allowing the muscle to produce high force economically and its tendon to store large amounts of elastic strain energy (9,10). A muscle that has a role of high-force production by little to no change in length of its fibers is less dependent on fast MHC isoforms and fast shortening velocities of the muscle fibers for peak in vivo performance.…”

“…For example, a shortfibered muscle with a long, compliant tendon suggests a capacity for substantial elastic energy storage, an effective means to reduce metabolic cost in locomotion (1). Recent interest in understanding how architecture of the equine digital flexors relates to their function in the distal limb during locomotion has led to in vivo studies examining 1) isometric force production for characterization of the passive and active force properties of DDF and SDF muscles (47) and 2) DDF and SDF contractile behavior and muscle-tendon unit function during walking and running (9,10). General findings from these studies indicate that the functional roles of these two synergistic muscles differ, with the DDF (short) having a capacity to shorten to generate modest work and power during locomotion, whereas the SDF has extremely limited shortening capability, doing mostly negative work (i.e., eccentric contractions), with a capacity for high-force production (high passive and active force) and large elastic energy storage in its tendon.…”

About the burden of the horse through the use of the rider

“…Verständnis ist der "'gute' Reiter", so konstatierten in der jün-geren Vergangenheit Denoix und Pailloux (1989) Pferdeheilkunde 31 (2015) 274 stung (Meershoek et al 2001, Thorpe et al 2010, Bucher et al 2007 (Stashak 1987, Preuschoft et al 1987b, Back et al 1995, Budiansky 1997, Back 2001, Clayton 2001 (Manfredi et al 2005, Stodulka 2009, Witzmann 2013, Eisersiö et al 2013, Meyer 2014. Generell treten orale Ulcera bei reiterlich genutzten Pferden signifikant häufiger als bei derart nicht eingesetzten Individuen auf (Tell et al 2008).…”

Avaliação da terapia por laser de arsenito e gálio em tendinite de cavalos Puro Sangue Inglês de corrida

“…Como são estruturas elásticas, eles servem para absorver impacto e são capazes de armazenar energia para ser utilizada no próximo passo (DENOIX, 1996;CLAYTON, 2004;BUTCHER et al, 2007 (MOFFAT et al, 2008;WEBBON, 1996;BIRCH, 1996;STEPHENS et al, 1989).…”