During a back tuck somersault, the angular velocity of the head is thought to surpass the visual system's ability to maintain a distinct and continuous picture of the environment. The primary objectives of this research were to determine if differences existed with regard to trunk and lower body kinematics, as well as landing balance, when gymnasts perform back tuck somersaults under different vision conditions. Ten female gymnasts (age = 11.6 ± 2.67 years, competitive level = 8 ± 1.15, and training time in gymnastics = 5.9 ± 1.63 years) performed back tuck somersaults under 4 vision conditions while wearing electromagnetic sensors that allowed automatic digitizing. Although no significant differences were found between vision conditions with regard to timing, joint angles, and joint angular velocities, gymnasts were more stable at landing under conditions that allowed vision during either the entire somersault or the last half of me somersault.
Christina D. Davlin, William A. Sands, and Barry B. Shultz
Freddie Bennett, Pat Eisenman, Ron French, Hester Henderson, and Barry Shultz
A single-subject multiple baseline design across subjects was used to discern the effect of a token economy on the exercise behavior and cardiorespiratory fitness of individuals with Down syndrome. The subjects were three females ranging in age from 24 to 26 years, with estimated IQs between 32 and 56. The exercise behavior consisted of pedaling a cycle ergometer for 15 min each weekday at 50-60% of peak VO2 for 6 to 8 weeks. Subjects voluntarily pedaled the cycle ergometer during the baseline phase, and after stabilization entered the intervention phase at 5-day intervals. During the intervention phase, tokens that could be exchanged for preferred items were dispensed for a predetermined number of revolutions. Based on the data and calculations using the split-middle technique, it was concluded that a token economy can be used to increase exercise behavior. Resting heart rates decreased 12.2%, and submaximal exercise heart rates, averaged over three work stages, decreased 18.8% over the course of the study. The small sample size, variable subject response, and a malfunctioning gas analyzer call for caution in inferring any possible cardiorespiratory fitness training effect.
James C. Martin, Steven J. Elmer, Robert D. Horscroft, Nicholas A.T. Brown, and Barry B. Shultz
The purpose of this study was to develop and evaluate an alternative method for determining the position of the anterior superior iliac spine (ASIS) during cycling. The approach used in this study employed an instrumented spatial linkage (ISL) system to determine the position of the ASIS in the parasagittal plane. A two-segment ISL constructed using aluminum segments, bearings, and digital encoders was tested statically against a calibration plate and dynamically against a video-based motion capture system. Four well-trained cyclists provided data at three pedaling rates. Statically, the ISL had a mean horizontal error of 0.03 ± 0.21 mm and a mean vertical error of −0.13 ± 0.59 mm. Compared with the video-based motion capture system, the agreement of the location of the ASIS had a mean error of 0.30 ± 0.55 mm for the horizontal dimension and −0.27 ± 0.60 mm for the vertical dimension. The ISL system is a cost-effective, accurate, and valid measure for two-dimensional kinematic data within a range of motion typical for cycling.
Brian T. McCormick, James C. Hannon, Maria Newton, Barry Shultz, Nicole Detling, and Warren B. Young
Plyometrics is a popular training modality for basketball players to improve power and change-of-direction speed. Most plyometric training has used sagittal-plane exercises, but improvements in change-of-direction speed have been greater in multidirection programs.
To determine the benefits of a 6-wk frontal-plane plyometric (FPP) training program compared with a 6-wk sagittal-plane plyometric (SPP) training program with regard to power and change-of-direction speed.
Fourteen female varsity high school basketball players participated in the study. Multiple 2 × 2 repeated-measures ANOVAs were used to determine differences for the FPP and SPP groups from preintervention to postintervention on 4 tests of power and 2 tests of change-of-direction speed.
There was a group main effect for time in all 6 tests. There was a significant group × time interaction effect in 3 of the 6 tests. The SPP improved performance of the countermovement vertical jump more than the FPP, whereas the FPP improved performance of the lateral hop (left) and lateral-shuffle test (left) more than the SPP. The standing long jump, lateral hop (right), and lateral-shuffle test (right) did not show a significant interaction effect.
These results suggest that basketball players should incorporate plyometric training in all planes to improve power and change-of-direction speed.
Heather Anne Hayes, Nikelle Hunsaker, Sydney Y. Schaefer, Barry Shultz, Thomas Schenkenberg, Lara A. Boyd, Andrea T. White, Kenneth B. Foreman, Philip Dyer, Rebecca Maletsky, and Leland E. Dibble
Deficits in sequence-specific learning (SSL) may be a product of Parkinson’s disease (PD) but this deficit could also be related to dopamine replacement. The purpose of this study was to determine whether dopamine replacement affected acquisition and retention of a standing Continuous Tracking Task in individuals with PD. SSL (difference between random/repeated Root Mean Square Error across trials) was calculated over 2 days of practice and 1 day of retention for 4 groups; 10 healthy young (HY), 10 healthy elders, 10 individuals with PD on, 9 individuals with PD off their usual dosage of dopamine replacement. Improvements in acquisition were observed for all groups; however, only the HY demonstrated retention. Therefore, age appeared to have the largest effect on SSL with no significant effect of medication. Additional research is needed to understand the influence of factors such as practice amount, task difficulty, and dopamine replacement status on SSL deficits during postural tasks.