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effects of box height on drop jump performance
Title
The effects of box height on drop jump performance.
Author
Addie, Cameron Douglas
Abstract/Description
Depth jumps (DJ) are commonly implemented in plyometric training programs in an attempt to enhance lower extremity jump performance. However, it is unknown how different box heights affect jump height (JH) and ground contact time (GCT). PURPOSE: The purpose of this study was to assess jump heights and ground contact time of depth jumps from various box heights. METHODS: Twenty college students who engaged in plyometric training (M = 13, F = 7; age: 22.80 ± 2.69 yr, height: 175.65 ± 11.81 cm,...
Show moreDepth jumps (DJ) are commonly implemented in plyometric training programs in an attempt to enhance lower extremity jump performance. However, it is unknown how different box heights affect jump height (JH) and ground contact time (GCT). PURPOSE: The purpose of this study was to assess jump heights and ground contact time of depth jumps from various box heights. METHODS: Twenty college students who engaged in plyometric training (M = 13, F = 7; age: 22.80 ± 2.69 yr, height: 175.65 ± 11.81 cm, mass: 78.32 ± 13.50 kg) performed DJs from 30 cm (DJ30), 45 cm (DJ45), 60 cm (DJ60), 76 cm (DJ76), and 91 cm (DJ91). A 16 camera Vicon system was used to track reflective markers bilaterally to calculate JH (ASIS, PSIS), while a Kistler force plate was used to record GCT. JH and GCT were compared using a 2x5 (sex x box height) repeated measures ANOVA. RESULTS: There was no interaction but there was a main effect for sex where both JH (M>F) and GCT (F>M) showed a significant M bias. There was no box height main effect for JH DJ30 (.4934 ± .1126 m), DJ45 (.5003 ± .1134m), DJ60 (.4936 ± .1195 m), DJ76 (.4957 ± .1105 m), DJ91 (.4783 ± .1162 m) but there was for GCT where DJ30 (.3584 ± .0971 s), DJ45 (.3605 ± .10528 s) and DJ 60 (.3723 ± .1049) were not significantly different from each other but were all less than DJ76 (.3962 ± .1161) and DJ91 (.4209 ± .1154). CONCLUSIONS: Increasing box height beyond 60cm increased GCT but did not affect JH. Therefore, practitioners designing plyometric training programs that implement DJs in order to increase JH may stop at a box height of 60cm. This would keep GCT minimal which might play a role in other power and speed events.
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Date Issued
2019
Identifier
1145027700, WFE0000682
Format
Document (PDF)
Effect of short term cross education training on contralateral shoulder strength
Title
Effect of short term cross education training on contralateral shoulder strength.
Author
Neltner, Tyler Joseph
Abstract/Description
The ability to train unilaterally and experience contralateral strength gains, a phenomenon known as cross-education, has been well documented in the lower extremity. Additionally, short-term training of one to two weeks has shown neural adaptations in strength. The purpose of this study is to examine the effects of a short-term cross-education strength-training program on contralateral shoulder strength. Twenty-seven healthy college students (age: 21.37 ± 2.02 years; height: 167.85 ± 7.63cm;...
Show moreThe ability to train unilaterally and experience contralateral strength gains, a phenomenon known as cross-education, has been well documented in the lower extremity. Additionally, short-term training of one to two weeks has shown neural adaptations in strength. The purpose of this study is to examine the effects of a short-term cross-education strength-training program on contralateral shoulder strength. Twenty-seven healthy college students (age: 21.37 ± 2.02 years; height: 167.85 ± 7.63cm; mass: 74.42 ± 16.73kg) were randomly assigned to either an experimental (n = 13) or control group (n = 14). Participants were tested at each of three speeds (60, 180, and 300d/s), completing six repetitions of shoulder internal/external rotation. The experimental group underwent right arm unilateral training two times a week for the next two weeks. No analysis could be done on 300d/s due to no load range data. Therefore, a 2x2x2x2 (time x arm x speed x group) ANOVA revealed no significant interactions by group; however, there were main effects of time and arm. Peak torque was significantly greater in the right arm and at 60d/s, and average power was significantly greater in the right arm and at 180d/s. Shortterm cross education training showed no increase in contralateral shoulder strength.
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Date Issued
2019, 2019
Identifier
1152895676, WFE0000695
Format
Document (PDF)
Ground reaction force comparison between barefoot and shod single leg landing at varied heights
Title
Ground reaction force comparison between barefoot and shod single leg landing at varied heights.
Author
Arnett, Jocelyn Esther
Abstract/Description
Landing is a common movement that occurs in many sports. Barefoot research has gained popularity in examining how shoes can alter natural movements. However, it is unknown how a single leg landing under barefoot conditions, as well as landing height, will affect ground reaction forces (GRF). PURPOSE: The purpose of this research was to examine the differences in ground reaction forces during a single leg landing under barefoot and shod conditions from various heights. METHODS: Sixteen female...
Show moreLanding is a common movement that occurs in many sports. Barefoot research has gained popularity in examining how shoes can alter natural movements. However, it is unknown how a single leg landing under barefoot conditions, as well as landing height, will affect ground reaction forces (GRF). PURPOSE: The purpose of this research was to examine the differences in ground reaction forces during a single leg landing under barefoot and shod conditions from various heights. METHODS: Sixteen female Division II collegiate athletes, 8 basketball (age: 19.88 ± 0.64 yrs; height: 1.77 ± 0.09 m; mass: 75.76 ± 12.97 kg) and 8 volleyball (age: 20.00 ± 1.07 yrs; height: 1.74 ± 0.08 m; mass: 72.41 ± 5.41 kg), performed single leg landings from 12 inches, 18 inches, 24 inches, and 30 inches barefoot and shod. An AMTI AccuGait force plate was used to record GRF. A 2 (condition) x 4 (box height) x 2 (sport) repeated measures ANOVA was performed to determine any GRF differences. RESULTS: There were no significant three way or two-way interactions for GRF (p > 0.05). There was also no main effect for sport (p > 0.05). There were main effects for footwear and box height (p = 0.000) where shod (2295.121 ± 66.025 N) had greater impact than barefoot (2090.233 ± 62.684 N). CONCLUSIONS: Single leg shod landing produced greater vertical ground reaction forces (vGRF) than during a barefoot landing. Current research continues to be contradictory on whether or not barefoot activities lower GRF; therefore, it is important to continue research in this area.
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Date Issued
2020, 2020
Identifier
1201541141, WFE0000709
Format
Document (PDF)