B. Humphries - Academia.edu (original) (raw)

Papers by B. Humphries

Research paper thumbnail of Comparison Of Two Techniques To Measure Musculotendinous Stiffness Of The Knee Flexors

Medicine & Science in Sports & Exercise, 2005

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Research paper thumbnail of Determining the Optimal Load for Jump Squats

Journal of Strength and Conditioning Research, 2004

ABSTRACT There has been an increasing volume of research focused on the load that elicits maximum... more ABSTRACT There has been an increasing volume of research focused on the load that elicits maximum power output during jump squats. Because of a lack of standardization for data collection and analysis protocols, results of much of this research are contradictory. The purpose of this paper is to examine why differing methods of data collection and analysis can lead to conflicting results for maximum power and associated optimal load. Six topics relevant to measurement and reporting of maximum power and optimal load are addressed: (a) data collection equipment, (b) inclusion or exclusion of body weight force in calculations of power, (c) free weight versus Smith machine jump squats, (d) reporting of average versus peak power, (e) reporting of load intensity, and (f) instructions given to athletes/ participants. Based on this information, a standardized protocol for data collection and reporting of jump squat power and optimal load is presented.

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Research paper thumbnail of Further evidence to change the medical classification system of the National Wheelchair Basketball Association

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Research paper thumbnail of Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

Journal of Strength and Conditioning Research, 2005

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athlet... more The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

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Research paper thumbnail of Whole-Body Vibration Effects on Bone Mineral Density in Women With or Without Resistance Training

Aviation, Space, and Environmental Medicine, 2009

Whole-body vibration exposure may translate into improved bone mass in young adult women. The pri... more Whole-body vibration exposure may translate into improved bone mass in young adult women. The primary focus of this study was to examine the effects of graded whole-body vibration or vibration exposure plus resistance training on bone mineral density (BMD), hematological measures for bone remodeling, and exercise metabolism in young women. There were 51 healthy active women [mean (SD) age, 21.02 (3.39) yr; height, 165.66 (6.73) cm; body mass 66.54 (13.39) kg] who participated in the intervention. Subjects were randomly assigned to whole-body vibration (WBV), whole-body vibration plus resistance training (WBV+RT), or control (CONT) groups for 16 wk. A repeated-measure ANOVA found no significant (P < 0.05) group differences in BMD at the completion of 16 wk. A significant within group change was apparent for the WBV (2.7% femoral neck) and WBV+RT (femoral neck 1.9%; vertebra 0.98%). WBV and WBV+RT experienced a significant (P < 0.05) 60% and 58% increase in adiponectin, 48% and 30% in transforming growth factor-beta1, and 17% and 34% in nitric oxide with an accompanying 50% and 36% decrease in osteopontin, 19% and 34% in interleukin-1beta, and 38% and 39% in tumor necrosis factor-alpha. The results indicate graded whole-body vibration exposure may be effective in improving BMD by increasing bone deposition while also decreasing bone resorption. Whole-body vibration may also provide an efficient stratagem for young women to achieve peak bone mass and help stave off osteoporosis later in life and provide a novel form of physical training.

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Research paper thumbnail of The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

Journal of sports science & medicine, 2004

At present there appears to be a need for research conducted on the effects of vibration on the c... more At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms(-2): displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration condition...

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Research paper thumbnail of Discriminating between elderly and young using a fractal dimension analysis of centre of pressure

International Journal of Medical Sciences, 2000

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Research paper thumbnail of Neuromechanical strategies employed to increase jump height during the initiation of the squat jump

Journal of Electromyography and Kinesiology, 2004

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Research paper thumbnail of Neuromechanical strategies employed to increase jump height during the initiation of the squat jump

Journal of Electromyography and Kinesiology, 2004

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

Journal of sports science & medicine, 2004

At present there appears to be a need for research conducted on the effects of vibration on the c... more At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms(-2): displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration condition...

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Research paper thumbnail of The intra-match activity variation during elite and sub-elite open-age Australian male basketball competitions

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Research paper thumbnail of A comparison of match activity demands between male and female state-level Australian basketball competitions

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Muscular fitness

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Research paper thumbnail of Moderate-Intensity Running Causes Intervertebral Disc Compression in Young Adults

Medicine & Science in Sports & Exercise, 2012

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Research paper thumbnail of The Effect of Resistance Training on Bone Strength in Women

Medicine & Science in Sports & Exercise, 2002

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Research paper thumbnail of Comparison Of Two Techniques To Measure Musculotendinous Stiffness Of The Knee Flexors

Medicine & Science in Sports & Exercise, 2005

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Research paper thumbnail of Effect of exercise intensity on bone density, strength, and calcium turnover in older women

Medicine & Science in Sports & Exercise, 2000

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Research paper thumbnail of The Effect of Short-Term Swiss Ball Training on Core Stability and Running Economy

Journal of Strength and Conditioning Research, 2004

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Research paper thumbnail of Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

Journal of Strength and Conditioning Research, 2005

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athlet... more The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-Reported Training Habits of Australian Outrigger Canoe PadΔers

Journal of Strength and Conditioning Research, 2002

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Research paper thumbnail of Comparison Of Two Techniques To Measure Musculotendinous Stiffness Of The Knee Flexors

Medicine & Science in Sports & Exercise, 2005

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Determining the Optimal Load for Jump Squats

Journal of Strength and Conditioning Research, 2004

ABSTRACT There has been an increasing volume of research focused on the load that elicits maximum... more ABSTRACT There has been an increasing volume of research focused on the load that elicits maximum power output during jump squats. Because of a lack of standardization for data collection and analysis protocols, results of much of this research are contradictory. The purpose of this paper is to examine why differing methods of data collection and analysis can lead to conflicting results for maximum power and associated optimal load. Six topics relevant to measurement and reporting of maximum power and optimal load are addressed: (a) data collection equipment, (b) inclusion or exclusion of body weight force in calculations of power, (c) free weight versus Smith machine jump squats, (d) reporting of average versus peak power, (e) reporting of load intensity, and (f) instructions given to athletes/ participants. Based on this information, a standardized protocol for data collection and reporting of jump squat power and optimal load is presented.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Further evidence to change the medical classification system of the National Wheelchair Basketball Association

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

Journal of Strength and Conditioning Research, 2005

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athlet... more The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Whole-Body Vibration Effects on Bone Mineral Density in Women With or Without Resistance Training

Aviation, Space, and Environmental Medicine, 2009

Whole-body vibration exposure may translate into improved bone mass in young adult women. The pri... more Whole-body vibration exposure may translate into improved bone mass in young adult women. The primary focus of this study was to examine the effects of graded whole-body vibration or vibration exposure plus resistance training on bone mineral density (BMD), hematological measures for bone remodeling, and exercise metabolism in young women. There were 51 healthy active women [mean (SD) age, 21.02 (3.39) yr; height, 165.66 (6.73) cm; body mass 66.54 (13.39) kg] who participated in the intervention. Subjects were randomly assigned to whole-body vibration (WBV), whole-body vibration plus resistance training (WBV+RT), or control (CONT) groups for 16 wk. A repeated-measure ANOVA found no significant (P < 0.05) group differences in BMD at the completion of 16 wk. A significant within group change was apparent for the WBV (2.7% femoral neck) and WBV+RT (femoral neck 1.9%; vertebra 0.98%). WBV and WBV+RT experienced a significant (P < 0.05) 60% and 58% increase in adiponectin, 48% and 30% in transforming growth factor-beta1, and 17% and 34% in nitric oxide with an accompanying 50% and 36% decrease in osteopontin, 19% and 34% in interleukin-1beta, and 38% and 39% in tumor necrosis factor-alpha. The results indicate graded whole-body vibration exposure may be effective in improving BMD by increasing bone deposition while also decreasing bone resorption. Whole-body vibration may also provide an efficient stratagem for young women to achieve peak bone mass and help stave off osteoporosis later in life and provide a novel form of physical training.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

Journal of sports science & medicine, 2004

At present there appears to be a need for research conducted on the effects of vibration on the c... more At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms(-2): displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration condition...

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Research paper thumbnail of Discriminating between elderly and young using a fractal dimension analysis of centre of pressure

International Journal of Medical Sciences, 2000

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Neuromechanical strategies employed to increase jump height during the initiation of the squat jump

Journal of Electromyography and Kinesiology, 2004

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Neuromechanical strategies employed to increase jump height during the initiation of the squat jump

Journal of Electromyography and Kinesiology, 2004

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

Journal of sports science & medicine, 2004

At present there appears to be a need for research conducted on the effects of vibration on the c... more At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms(-2): displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration condition...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The intra-match activity variation during elite and sub-elite open-age Australian male basketball competitions

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A comparison of match activity demands between male and female state-level Australian basketball competitions

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Muscular fitness

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Moderate-Intensity Running Causes Intervertebral Disc Compression in Young Adults

Medicine & Science in Sports & Exercise, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Effect of Resistance Training on Bone Strength in Women

Medicine & Science in Sports & Exercise, 2002

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Comparison Of Two Techniques To Measure Musculotendinous Stiffness Of The Knee Flexors

Medicine & Science in Sports & Exercise, 2005

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of exercise intensity on bone density, strength, and calcium turnover in older women

Medicine & Science in Sports & Exercise, 2000

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Effect of Short-Term Swiss Ball Training on Core Stability and Running Economy

Journal of Strength and Conditioning Research, 2004

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

Journal of Strength and Conditioning Research, 2005

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athlet... more The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Self-Reported Training Habits of Australian Outrigger Canoe PadΔers

Journal of Strength and Conditioning Research, 2002

Bookmarks Related papers MentionsView impact