Swimming in the rat: Analysis of locomotor performance in comparison to stepping

Gruner, John A.; Altman, Joseph

doi:10.1007/bf00236146

Cited by 94 publications

(69 citation statements)

References 15 publications

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“…Indeed, during running, TA and EDL contract for most of the time against the inertial torque generated at the ankle by protraction of the hindlimb, counteracting stretching forces [1,7]. By contrast, during swimming, the ankle flexors contract against water resistance with extensive shortening, as do the extensors, and thus both groups of muscles exhibh a clear dynamic activity [4]. The G+ increase displayed by the ankle flexors following swimming training mgnificantly strengthens the proposal that the G4 content of the fast muscles ts high or low accordlng to whether the actual activity the muscle is called upon to perform Is predominantly dynamic or tonic [1],…”

Section: Discussionmentioning

confidence: 99%

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Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors

Gisiger¹,

Sheker

Gardiner

1991

FEBS Letters

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The effect ofendurnm¢ ~wtmminil t~mnln8 on AChE ntok~ul=r forms was tx,mln~ in 2 i;roup* of function#lly antagonist mt muscles, includm8 .nkle extensora and flexors This ¢xercin r0itlmen, which cnt.ll, predomln.nt dynamic activity (i ¢. Involvi~$ extensive ,hortcnlnll) of both Iproups of mu~l=,=, re=ultcd in m~rkcd sel~ttvc O.. increases in .11 f~tt mu~k=s The O,b elevation ¢,chibhed by the ~nkle Ilexors w=tt In .harp contrast to the O. reduction reported in these J,,,ma muscles following running trmnmll, durln8 which their action t'= predominantly tonic The r~sults strenllthen the conclusion that predomlmmtly dynamic ttcttvity increams the 04 content of mature innervttted fast mullet, Acetylehoimeste~s¢ molccuhtr form, Acetykhohnesteras¢ ,d~tptatmn to a©tivhy: Mut¢l¢ plaltictty, Exer¢l~

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Section: Discussionmentioning

confidence: 99%

“…We chose this type of exercise because, in Gpposition to running, swimming entails a clear dynamic activity of both ankle extensors and flexors [4]. We therefore anticipated the swimming training program to result in a G4 increase in the 2 groups of muscles, including the fast ankle flexors TA and EDL.…”

Section: Introductionmentioning

confidence: 99%

Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors

Gisiger¹,

Sheker

Gardiner

1991

FEBS Letters

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“…Consideration of all of these muscle groups was necessary to evaluate the contributions of biarticular ankle extensors to total moments at the knee joint that might elevate the forces exerted by muscles spanning the femur (Alexander, 1974;Biewener, 1983;Schoenfuss et al, 2010). Because published data on hindlimb muscle activity were unavailable for opossums, our assessments of which muscles to consider followed the precedent of previous force-platform-based analyses of bone loading in small mammals (Biewener, 1983) and drew from available electromyographic (EMG) data for rats and cats (Rasmussen et al, 1978;Sullivan and Armstrong, 1978;Gruner and Altman, 1980;Roy et al, 1991;Gillis and Biewener, 2001;Thota et al, 2005) to supplement anatomical assessments of function specific for opossums (Romer, 1922).…”

Section: Model Of Hindlimb Muscle Activity and Bone Stress Analysesmentioning

confidence: 99%

Femoral loading mechanics in the Virginia opossum,Didelphis virginiana: torsion and mediolateral bending in mammalian locomotion

Gosnell

Butcher

Maie

et al. 2011

Journal of Experimental Biology

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SUMMARYStudies of limb bone loading in terrestrial mammals have typically found anteroposterior bending to be the primary loading regime, with torsion contributing minimally. However, previous studies have focused on large, cursorial eutherian species in which the limbs are held essentially upright. Recent in vivo strain data from the Virginia opossum (Didelphis virginiana), a marsupial that uses a crouched rather than an upright limb posture, have indicated that its femur experiences appreciable torsion during locomotion as well as strong mediolateral bending. The elevated femoral torsion and strong mediolateral bending observed in D. virginiana might result from external forces such as a medial inclination of the ground reaction force (GRF), internal forces deriving from a crouched limb posture, or a combination of these factors. To evaluate the mechanism underlying the loading regime of opossum femora, we filmed D. virginiana running over a force platform, allowing us to measure the magnitude of the GRF and its three-dimensional orientation relative to the limb, facilitating estimates of limb bone stresses. This three-dimensional analysis also allows evaluations of muscular forces, particularly those of hip adductor muscles, in the appropriate anatomical plane to a greater degree than previous two-dimensional analyses. At peak GRF and stress magnitudes, the GRF is oriented nearly vertically, inducing a strong abductor moment at the hip that is countered by adductor muscles on the medial aspect of the femur that place this surface in compression and induce mediolateral bending, corroborating and explaining loading patterns that were identified in strain analyses. The crouched orientation of the femur during stance in opossums also contributes to levels of femoral torsion as high as those seen in many reptilian taxa. Femoral safety factors were as high as those of non-avian reptiles and greater than those of upright, cursorial mammals, primarily because the load magnitudes experienced by opossums are lower than those of most mammals. Thus, the evolutionary transition from crouched to upright posture in mammalian ancestors may have been accompanied by an increase in limb bone load magnitudes.

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“…However, such motor stereotypy might be found if a central pattern generator were the dominant source of control for the muscles in question (Buford and Smith, 1990;Pratt et al, 1996;Blob et al, 2008), possibly simplifying locomotor control in systems with serially homologous appendages. A second possible strategy is that the same set of muscles might be recruited across behaviors, but with differences in timing or intensity of activity (Gruner and Altman, 1980;Roy et al, 1985;Macpherson, 1991;Roy et al, 1991;Johnston and Bekoff, 1996;Kamel et al, 1996;Gillis and Biewener, 2000;Reilly and Blob, 2003;Blob et al, 2008). Depending on the functional demands and requirements of the motion in question, some general patterns of coactivation may be maintained with only small differences in the intensity or timing of muscle activity (Gruner and Altman, 1980;Johnston and Bekoff, 1996).…”

Section: Introductionmentioning

confidence: 99%

Forelimb kinematics and motor patterns of the slider turtle (Trachemys scripta) during swimming and walking: shared and novel strategies for meeting locomotor demands of water and land

Rivera

Blob

2010

Journal of Experimental Biology

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SUMMARYTurtles use their limbs during both aquatic and terrestrial locomotion, but water and land impose dramatically different physical requirements. How must musculoskeletal function be adjusted to produce locomotion through such physically disparate habitats? We addressed this question by quantifying forelimb kinematics and muscle activity during aquatic and terrestrial locomotion in a generalized freshwater turtle, the red-eared slider (Trachemys scripta), using digital high-speed video and electromyography (EMG). Comparisons of our forelimb data to previously collected data from the slider hindlimb allow us to test whether limb muscles with similar functional roles show qualitatively similar modulations of activity across habitats. The different functional demands of water and air lead to a prediction that muscle activity for limb protractors (e.g. latissimus dorsi and deltoid for the forelimb) should be greater during swimming than during walking, and activity in retractors (e.g. coracobrachialis and pectoralis for the forelimb) should be greater during walking than during swimming. Differences between aquatic and terrestrial forelimb movements are reflected in temporal modulation of muscle activity bursts between environments, and in some cases the number of EMG bursts as well. Although patterns of modulation between water and land are similar between the fore-and hindlimb in T. scripta for propulsive phase muscles (retractors), we did not find support for the predicted pattern of intensity modulation, suggesting that the functional demands of the locomotor medium alone do not dictate differences in intensity of muscle activity across habitats. Supplementary material available online at

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Swimming in the rat: Analysis of locomotor performance in comparison to stepping

Cited by 94 publications

References 15 publications

Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors

Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors

Femoral loading mechanics in the Virginia opossum,Didelphis virginiana: torsion and mediolateral bending in mammalian locomotion

Forelimb kinematics and motor patterns of the slider turtle (Trachemys scripta) during swimming and walking: shared and novel strategies for meeting locomotor demands of water and land

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Swimming in the rat: Analysis of locomotor performance in comparison to stepping

Cited by 94 publications

References 15 publications

Swimming training increases the G4 acetylcholinesterase content of both fast ankle extensors and flexors

Swimming training increases the G4 acetylcholinesterase content of both fast ankle extensors and flexors

Femoral loading mechanics in the Virginia opossum,Didelphis virginiana: torsion and mediolateral bending in mammalian locomotion

Forelimb kinematics and motor patterns of the slider turtle (Trachemys scripta) during swimming and walking: shared and novel strategies for meeting locomotor demands of water and land

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Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors

Swimming training increases the G₄ acetylcholinesterase content of both fast ankle extensors and flexors