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Wei Liu, Jill Whitall, and Thomas M. Kepple

Functional arm reaching involves multilinked joints: shoulder, elbow, and wrist. We propose that induced position analysis is a useful analytical tool for multijoint coordination of arm reaching. This method was used to compute the contributions of the net joint moment to the hand position when reaching forward. We describe the method and give examples of validating this model with motion capture data. The shoulder and elbow were prime movers of the arm: both acted together with an “overshoot” and “undershoot” pattern respectively to move the hand forward into the final position.

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Rini Varghese, Christina W.Y. Hui-Chan, and Tanvi Bhatt

This study quantified the effect of aging and the long-term practice of Tai Chi on upper limb movement control, indicated by performance outcome (temporal) and performance production (amplitude) measures, on a multiplanar stand-reaching (i.e., functional) task. Twelve Tai Chi practitioners (TCPs), 11 age-matched older nonpractitioners (ONPs), and 12 young subjects performed cued, flexion-reaching, and abduction-reaching tasks using a custom set-up. Surface EMG and acceleration data sampled from wireless sensors rendered performance outcome (reaction time, burst duration, time to peak, and movement time) and performance production (normalized EMG amplitude and peak acceleration) measures. Young subjects and TCPs demonstrated better performance outcome and performance production than ONPs. Relative-effect computations (i.e., the effect of Tai Chi expressed as a percentage of the effect of aging) showed that TCPs exhibited approximately 20–60% (flexion) and 20–100% (abduction) improvement in reaching task performance compared with ONPs. Tai Chi practitioners displayed better arm movement control than ONPs on a relatively challenging and functional stand-reaching task.

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Kathye E. Light, Marie A. Reilly, Andrea L. Behrman, and Waneen W. Spirduso

The purpose of this study was to examine the effect of practice on simple reaction time (RT), movement time (MT), and response consistency for two arm-reaching tasks of graded complexity in younger and older adults. Forty subjects, 20 younger adults (age range = 20–29 years) and 20 older adults (age range = 60–82 years), were randomly subdivided into practice and control groups. All subjects were pretested on each arm-reaching movement on Day 1. The practice groups practiced each task for 160 trials over 2 consecutive days while the control groups practiced a memory task and answered a health survey. All subjects were posttested on Day 3. The major finding was that practice reduced the simple RTs of older persons to the level of younger persons. MTs for both practice age groups were reduced, but the age differences in MT performance were maintained.

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Katelyn M. Christian and Matthew F. Moran

score. ▸ Reach direction sequence significantly influenced medial reach when stabilizing with the nonthrowing arm. ▸ Reach direction sequence should be held consistent for repeat testing. Softball is a sport of repetitive overhead throwing motions requiring glenohumeral (GH) abduction and external

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Micheal J. Luera, Brittany Dowling, Tyler W.D. Muddle, and Nathaniel D.M. Jenkins

other between maximum foot height and foot contact. Maximum elbow extension was the instant the elbow reached a maximum extension angle before foot contact. Maximum throwing arm external rotation was established as the frame in which the throwing arm reached maximum external rotation. Ball release was

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Arturo Forner-Cordero, Virgínia H. Quadrado, Sitsofe A. Tsagbey, and Bouwien C.M. Smits-Engelsman

prescribed task. Haith and Krakauer ( 2014 ) observed this number to be between 10 and 30 movements in arm reaching tasks under force field conditions. However, it has been suggested that the type of perturbation applied can alter the characteristics of that adaptation. Notably, gradual and unnoticed

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Bareket Falk and Raffy Dotan

inappropriate for young or small children (eg, saddle height, crank length, pedal size, or arm reach). Although pediatric-specific cycle-ergometers and adjustable cranks that can accommodate even the smallest children are now commercially available, important factors in maximizing cycling performance are proper

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Derrick D. Brown, Jurjen Bosga, and Ruud G.J. Meulenbroek

synergies during arm reaching movements involving the trunk . Journal of Neurophysiology, 73 ( 5 ), 2120 – 2122 . PubMed ID: 7623104 doi:10.1152/jn.1995.73.5.2120 10.1152/jn.1995.73.5.2120 Matsumura , K. , Yamamoto , T. , & Fujinami , T. ( 2011 ). The role of body movement in learning to play the

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Robert MacKenzie, Linda Monaghan, Robert A. Masson, Alice K. Werner, Tansinee S. Caprez, Lynsey Johnston, and Ole J. Kemi

ability did not improve. This strengthens the role of the main determinants identified here as key performance indicators, though the full effect of training should be studied in more depth. Our results also suggest, with the possible exception for hand and arm reach, that nontrainable anthropometric and

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Luke Hogarth, Mark McKean, Max McKenzie, and Tyler Collings

) = .96. 18 The vertical jump height was measured using a Vertec (Swift Yardstick, Swift Performance) and the procedure detailed previously. 24 Briefly, after the maximum reach height was established with a full overhead single arm reach to clear the lowest vane, keeping both feet flat on the floor, the