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Effects of rung spacing on the mechanics of ladder ascent
Abstracts
497
EFFECTS OF RUNG SPACING ON THE MECHANICS OF LADDER ASCENT D. R. MCINTYRE BATES
(Biomechanics (Biomechanics/Sports
Lab., North Texas State University, Denton. TX) and B. T Medicine Lab., University of Oregon. Eugene, OR)
Twenty male subjects grouped according to their standing heights, each performed 3 climbing trials. Each trial corresponded to one of three selected rung spacing conditions. Temporal, kinematic and kinetic measures of each performance were recorded. Significant temporal differences were found between the rung spacing conditions. The kinematic analysis revealed characteristic movement patterns displayed by each limb segment for each condition. The kinematic analysis showed that the primary role of the hands was for the maintenance of stabili ty in a direction perpendicular to the ladder uprights with the magnitudes of the forces being subject group dependent. The primary role of the forces directed through the feet was found to be for the vertical elevation of the body. Abnormalities in the temporal, kinematic and kinetic characteristics of the gait cycles were related to an increased potential for the occurrence of a climbing accident. CORRELATION
OF DEGREE OF INDUCED
CONCUSSION
WITH THE DEGREE OF EXCITATIOU OF
RESONANT FREQUENCY. RESULTING FROM HEAD IMPACT IN f MACACA SPECIOSA JOHN
THE STUMPT.*IL MOVtiE1
I
E. KOI-WICK (Pleasant
Ridge, MI)
Some investigators of head impact trauma have suggested that resonance of the head may contribute IO the severity of the trauma. Todetermineifsuch a correlation does exist, thedata from impacts to the heads of6 female stumptail monkeys were analyzed. The animal’s heart rate and respiration were recorded to assess the duration of an induced concussion, and the acceleration-time history from a calvarium-mounted accelerometer was Fourieranalyzed to determine the energy level at the surrogate’s reasonant frequency of 1700 Hz. Little correlation was exhibited when either the rise-time only portion of the acceleration-time history was analyzed. or the full pulse wave form was statistically analyzed. BIOMECHANICAL
ANALYSES OF LOAD LIFTI’iG
A. FREIVALDS,D. B. CHAFFIN and K. S. LEE (Industrial and Operations Engineering. University of Michigan, Center for Ergonomics. MI)
The
To better understand the effects of load and posture on joint torques, the motion dynamics of 6 subjects lifting maximum loads in 4 different types of containers from floor to table height were examined. Jomr center coordinates from photographs, ground reaction forces from a force platform and EMG from the erector spinae at the L, S, joint were analyzed and entered into a 7 link, dynamic biomechanical model. Container size shoaed little effect. Containers without handles produced slower rise times and smaller peab ground reaction forces as opposed to containers with handles, indicating more controlled movements. Smoothed and rectified EMG showed similar responses having good correlation with the ground reaction forces. These records also allnaed Lalidation of low back compressive forces as calculated by the model. I. LOCO%1OTIO\
LOCOMOTION RICHARD
STUDI&CA\‘ES
TO COMPCTERS
A. BRAND and ROY D. CROWNINSHIELD(Biomechanics Laborator!. Orthopaedic Surgery, University of Iowa. Iowa City, IA)
Department
of
Locomotion has aroused the interest of man since at least the beginning of recorded histor!. The study of locomotion has paralleled the development ofsciences in general. with philosophy. motivation. technolop!. and sometimes theology or politics being intimately interrelated. As in any science, advances are usually e\olurlonary and not ordinarily totally attributable to a single individual; nonetheless. the citing of Individual work> 1s useful for temporally placing those advances. We traced the introduction of the important concepts related to locomotion research from cave drawings to the present time. Such a historical perspective aids present Investigations by providing an analytical tool to understand our own works and to prolect future research trends. THE EFFECTS OF RUSSINC
SHOES ON RU\\ERS’
GROI’SD
REACrl\
E FORCES
R. STRAIK. J. BALL, C. STANITSKI, L. MICHELI, J. MANSOUR and S. R. SIVO~ (Gait Analyslb Laboratory, Children’s Hospital Medical Center. Boston. hl A I Experienced ( > 50 miles/week)and inexperienced runners ran in a gait lab. over two forceplates. Ground reactive forces were recorded (vertical, fore-aft, medial-lateral) and sampled at 500 Hz. Runnln s \elocit\ _ \\a> me;l>urrd
497
EFFECTS OF RUNG SPACING ON THE MECHANICS OF LADDER ASCENT D. R. MCINTYRE BATES
(Biomechanics (Biomechanics/Sports
Lab., North Texas State University, Denton. TX) and B. T Medicine Lab., University of Oregon. Eugene, OR)
Twenty male subjects grouped according to their standing heights, each performed 3 climbing trials. Each trial corresponded to one of three selected rung spacing conditions. Temporal, kinematic and kinetic measures of each performance were recorded. Significant temporal differences were found between the rung spacing conditions. The kinematic analysis revealed characteristic movement patterns displayed by each limb segment for each condition. The kinematic analysis showed that the primary role of the hands was for the maintenance of stabili ty in a direction perpendicular to the ladder uprights with the magnitudes of the forces being subject group dependent. The primary role of the forces directed through the feet was found to be for the vertical elevation of the body. Abnormalities in the temporal, kinematic and kinetic characteristics of the gait cycles were related to an increased potential for the occurrence of a climbing accident. CORRELATION
OF DEGREE OF INDUCED
CONCUSSION
WITH THE DEGREE OF EXCITATIOU OF
RESONANT FREQUENCY. RESULTING FROM HEAD IMPACT IN f MACACA SPECIOSA JOHN
THE STUMPT.*IL MOVtiE1
I
E. KOI-WICK (Pleasant
Ridge, MI)
Some investigators of head impact trauma have suggested that resonance of the head may contribute IO the severity of the trauma. Todetermineifsuch a correlation does exist, thedata from impacts to the heads of6 female stumptail monkeys were analyzed. The animal’s heart rate and respiration were recorded to assess the duration of an induced concussion, and the acceleration-time history from a calvarium-mounted accelerometer was Fourieranalyzed to determine the energy level at the surrogate’s reasonant frequency of 1700 Hz. Little correlation was exhibited when either the rise-time only portion of the acceleration-time history was analyzed. or the full pulse wave form was statistically analyzed. BIOMECHANICAL
ANALYSES OF LOAD LIFTI’iG
A. FREIVALDS,D. B. CHAFFIN and K. S. LEE (Industrial and Operations Engineering. University of Michigan, Center for Ergonomics. MI)
The
To better understand the effects of load and posture on joint torques, the motion dynamics of 6 subjects lifting maximum loads in 4 different types of containers from floor to table height were examined. Jomr center coordinates from photographs, ground reaction forces from a force platform and EMG from the erector spinae at the L, S, joint were analyzed and entered into a 7 link, dynamic biomechanical model. Container size shoaed little effect. Containers without handles produced slower rise times and smaller peab ground reaction forces as opposed to containers with handles, indicating more controlled movements. Smoothed and rectified EMG showed similar responses having good correlation with the ground reaction forces. These records also allnaed Lalidation of low back compressive forces as calculated by the model. I. LOCO%1OTIO\
LOCOMOTION RICHARD
STUDI&CA\‘ES
TO COMPCTERS
A. BRAND and ROY D. CROWNINSHIELD(Biomechanics Laborator!. Orthopaedic Surgery, University of Iowa. Iowa City, IA)
Department
of
Locomotion has aroused the interest of man since at least the beginning of recorded histor!. The study of locomotion has paralleled the development ofsciences in general. with philosophy. motivation. technolop!. and sometimes theology or politics being intimately interrelated. As in any science, advances are usually e\olurlonary and not ordinarily totally attributable to a single individual; nonetheless. the citing of Individual work> 1s useful for temporally placing those advances. We traced the introduction of the important concepts related to locomotion research from cave drawings to the present time. Such a historical perspective aids present Investigations by providing an analytical tool to understand our own works and to prolect future research trends. THE EFFECTS OF RUSSINC
SHOES ON RU\\ERS’
GROI’SD
REACrl\
E FORCES
R. STRAIK. J. BALL, C. STANITSKI, L. MICHELI, J. MANSOUR and S. R. SIVO~ (Gait Analyslb Laboratory, Children’s Hospital Medical Center. Boston. hl A I Experienced ( > 50 miles/week)and inexperienced runners ran in a gait lab. over two forceplates. Ground reactive forces were recorded (vertical, fore-aft, medial-lateral) and sampled at 500 Hz. Runnln s \elocit\ _ \\a> me;l>urrd