This study compared interlimb coordination and indicators of swim efficiency and effectiveness between expert and recreational breaststroke swimmers. Arm-leg coordination of 8 expert and 10 recreational swimmers at two different paces, slow and sprint, were compared using relative phase between elbow and knee. For each participant, knee and elbow angles were assessed using a 3-dimensional video analysis system with four below and two above cameras. During each phase of the cycle, indicators of swim efficiency (intracyclic velocity variations) and effectiveness (horizontal distance, velocity peaks, acceleration peaks) were calculated. Two coordination patterns emerged between expert and recreational swimmers, with significant differences in the relative phase at the beginning of a cycle (−172.4° for experts and −106.6° for recreational swimmers) and the maximum value of relative phase (9.1° for experts and 45.9° for recreational swimmers; all P < .05). Experts’ coordination was associated with higher swim effectiveness (higher acceleration peak: 2.4 m/s2 for experts and 1.6 m/s2 for recreational swimmers) and higher distance covered by the center of mass during each phase of the cycle (all P < .05). This study emphasized how experts coordinate arms and legs to achieve effective behavior, therefore exhibiting flexibility, mainly in the timing of the glide phase, to adapt to different speed.
Search Results
Do Qualitative Changes in Interlimb Coordination Lead to Effectiveness of Aquatic Locomotion Rather Than Efficiency?
John Komar, Ross H. Sanders, Didier Chollet, and Ludovic Seifert
Visual Feedforward Control in Human Locomotion During Avoidance of Obstacles that Change Size
Luiz C. Santos, Renato Moraes, and Aftab E. Patla
The purpose of the current study was to understand how visual information about an ongoing change in obstacle size is used during obstacle avoidance for both lead and trail limbs. Participants were required to walk in a dark room and to step over an obstacle edged with a special tape visible in the dark. The obstacle’s dimensions were manipulated one step before obstacle clearance by increasing or decreasing its size. Two increasing and two decreasing obstacle conditions were combined with seven control static conditions. Results showed that information about the obstacle’s size was acquired and used to modulate trail limb trajectory, but had no effect on lead limb trajectory. The adaptive step was influenced by the time available to acquire and process visual information. In conclusion, visual information about obstacle size acquired during lead limb crossing was used in a feedforward manner to modulate trail limb trajectory.
The Effect of Nonspecific Task Constraints on Quadrupedal Locomotion: I. Interlimb Coordination
Jill Whitall, Larry Forrester, and Nancy Getchell
The present study examined the effect of nonspecific task constraints on the multilimb coordination task of preferred-speed crawling. Adult subjects undertook three trials each of the following randomly ordered conditions: forward prone (FP), backward supine (BS), backward prone (BP) and forward supine (FS). Subjects adopted specific coordinative solutions consistent with task-related function rather than anatomical specification. The patterns were relatively stable, with BP being least stable. Across conditions, subjects changed their velocity in a predictable order that corresponded to the various constraints. These velocity changes were largely attributable to stride length adjustments and not limb frequency. Within a condition, neither velocity nor anthropometrics appeared to influence the coordinative solution. Overall, rather large differences were found in coordinative solutions, possibly owing to the nature of the tasks and/or individual searching strategies. The results were interpretable within a dynamic approach to coordination and support the idea that coordination is functionally rather than anatomically determined.
The Effect of Nonspecific Task Constraints on Quadrupedal Locomotion: II. Joint Kinematics
Larry Forrester and Jill Whitall
The effects of directional and postural constraints on preferred speed quadrupedal gait patterns were studied by comparing responses to four hand-foot crawling tasks: forward and backward prone (FP and BP) and forward and backward supine (FS and BS). A central question was whether the task dynamics evident at the end-effector level also appear at the joint effector system level. Timing of reversals in each limb's proximal effector system joints was shown to be related to the functional role (propulsion or reaching) of the limb. Within joints, task constraint changes strongly tended to affect reversal times, and time-reversed directional comparisons tended to show “mirroring” responses. Peak reaching positions were also closely associated with forelimb touchdowns and interlimb coordination. Discussion centers on task function, task dynamics, and their influence on effector system behavior.
Terrestrial Locomotion in the Black-Billed Magpie. I. Spatio-Temporal Gait Characteristics
Myriam Verstappen and Peter Aerts
Spatio-temporal gait characteristics are determined for walking, running, and out of phase hopping magpies, at velocities ranging from 0.4 to 4 m/s. Below 1 m/s, magpies walk. At higher velocities they either run or hop, the latter being preferred. Stride length and frequency during walking and running relate to speed in an identical way. It is suggested that the control of walking and running, despite the abrupt drop in duty factor and step length at the transition from walking to either running or hopping, is represented by one single intrinsic pattern. Swing phase duration is independent of speed and similar of the three gaits, pointing to a passive, mechanical control. Stride frequencies during hopping barely change with velocity, while its stride length relates to velocity in a way highly comparable to that of walking and running. Hopping step length and duty factor are indifferent from those of running. These facts, combined with the similar spatio-temporal behavior of both legs in hopping suggest fairly comparable intra-limb coordination for running and hopping, and a simple phase-shift in inter-limb coordination to transform a run into a hop.
Increases in Load Carriage Magnitude and Forced Marching Change Lower-Extremity Coordination in Physically Active, Recruit-Aged Women
Dennis E. Dever, Kellen T. Krajewski, Camille C. Johnson, Katelyn F. Allison, Nizam U. Ahamed, Mita Lovalekar, Qi Mi, Shawn D. Flanagan, William J. Anderst, and Chris Connaboy
bipedal ambulation has developed 2 distinct models of locomotion: (1) the inverted pendulum model for walking where individuals essentially vault from one stiff leg to the next 7 – 10 and (2) the spring mass model for running where individuals utilize elastic energy to spring forward. 8 , 11 – 14 As
Stable Coordination Variability in Overground Walking and Running at Preferred and Fixed Speeds
Hannah E. Wyatt, Gillian Weir, Carl Jewell, Richard E.A. van Emmerik, and Joseph Hamill
measure of an individual or group and may have a considerable effect on the reliability and subsequent interpretation of the research finding. 4 Previous research investigating CV during locomotion has been informed by trial numbers ranging from 5 5 – 7 to 15. 8 , 9 Various features of locomotion are
Unprompted Alteration of Freely Chosen Movement Rate During Stereotyped Rhythmic Movement: Examples and Review
Ernst Albin Hansen
Voluntary stereotyped rhythmic movement constitutes a fundamental element of a number of everyday activities performed by humans. Locomotion and cycling are obvious and well-known examples. It has previously been described that such activities can be performed in an automated and continuous way for
Altered Spatiotemporal Gaze Dynamics During Unexpected Obstacle Negotiation in a Fatigued State
Jacob W. Hinkel-Lipsker, Nicole M. Stoehr, Pranavi L. Depur, Michael A. Weise, Joshua A. Vicente, Stefanie A. Drew, and Sean M. Rogers
locomotion. Some work has also used experimental methods to occlude a walker’s peripheral visual field ( Graci et al., 2009 ; Jansen et al., 2010 ; Rietdyk & Rhea, 2006; Rodrigues et al., 2009 ) or to blur their vision ( Novak & Deshpande, 2014 ). Less studied, however, are how acute physiological
The Perceived Motor Competence Questionnaire in Childhood (PMC-C)
Dennis Dreiskaemper, Till Utesch, and Maike Tietjens
develop fundamental motor skills throughout childhood (i.e., motor competence; locomotion and object-control, Burton & Miller, 1998 ). In this regard, a few instruments already exist, but only for early childhood (e.g., Harter, 1982 ). Additionally, these instruments do not provide differentiation in
