Michael Orendurff | Independent Researcher (original) (raw)
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Books by Michael Orendurff
"No, I don't think this is it." My brother said while peering through the trees in the directio... more "No, I don't think this is it." My brother said while peering through the trees in the direction of what was once a trail. We had been hopping logs for an hour as the path methodically deteriorated into the faint shadow of a bad memory we were now trying to detect from the forest in general. The sun had just slid down behind the hills and it would be dark in another hour. Our water was low. This was a fitting end to a tour that had not gone entirely well.
We had been circling the Roaring River drainage for three days, first on Abbot road, then on forest road 240 (seven flats until a hidden piece of glass was discovered deeply imbedded in the tire) to the start of the Serene Lake trail at Fraiser turnaround. It was late August and hot as hell. The trail was only slightly rough, and upon arrival, Serene Lake looked welcoming. Welcoming, until we noticed the yellow jackets were out in full force, a hive about every twenty feet around the lake. Never the less, we decided to chance a swim. In one fateful instant, on a rock on the shore, my brother received a dreaded injury. For the next five hours he would nurse a swelling sting on the second most sensitive region of the body. He said he couldn't sit straight on his bike because his ass had become lop-sided. The insect had apparently been studying anatomy and chose the flesh covering the ischial tuberosity (look it up) as the sight to inflict the most damage to a cyclist. We struggled up from the lake, the lake which my brother had re-named many times over by now, to the junction with the Grouse Point trail #517 and began heading north along the even grade.
After an hour of scraping through overgrown rhododendrons, and passing Grouse Point for which the trail is named, we came to what we thought was our salvation - the downhill section of the Dry Ridge trail #518, eyed weeks earlier on a map, from the comfort of a futon couch. How I longed to be on that couch at that very moment, as my brother peered through the trees, his eyes searching in vain for the extinct trail.
On the map it had looked like a straight-shot 3000 foot downhill with raging switchbacks and hairpin corners descending to the Roaring River campground. Total bliss. But our bliss was ignorant. We expected the forest service to be able to maintain a trail that they themselves said existed, and to sign it with some competency, but this was more than could be expected of this usually fine institution.
Now, with darkness looming, my brother was shifting his head from side to side, leaning at a grotesque angle that favored his left cheek, attempting to see past the trees.
"There's a clearing up there. Maybe it's a campground." His hopefulness was discouraging.
I turned to look back the way we had come, reviewing the trail in my mind and how much work it would be to go back up the last two miles. "Lets get the map," I moaned for the fourth or fifth time. Malcolm dragged it out of his handlebar bag, and I peeled back the map's dog-eared corners, going cross-eyed in microscopic study of the frequently cursed document. "This should be here." I said, pointing to a spot on the map worn from finger pointing.
"Definitely a clearing." He said, looking again downhill. He wasn't listening to me.
"What?"
Malcolm threw his bike down and began to walk over the logs, crackling on the thinner sticks that littered the ground. A clearing did appear, and then a logging road, a road that was nowhere near the trail on which we were supposed to be riding. We had been led astray.
Deciding that we knew where we were, the one choice with only moderate insanity was to follow the road to where we could bush-whack toward where we thought the real trail was. The feeling of impending doom rose in my stomach as we returned to get the bikes. We rode warily down the logging road, braking constantly and peering about. If we were wrong, it would be a long way back up.
On a corner that seemed to be the closest to our trail, we paced back and forth, setting our compass. Finally a bearing was decided on and we struck out across the most gnarly mound of blowdown intricately laced with thriving vine maples and patrolled by hundreds of yellow jackets. Every forest gnome reached out to grab our wheels, impale sticks through our frames, scratch our faces, legs and hands. It was a pleasant mountain bike drag-through-the-woods. The fear of being completely wrong in our hypothesis was drying my mouth like a spoonful of raw oatmeal.
We wheezed and pulled and cursed until suddenly the trail appeared. The right trail, a weaving, smooth and curvaceous trail, well maintained and without logs and only a few sticks lying in wait. A trail right out of my living room. The trail of safe, futon dreams –here it was.
The last of the suns rays disappeared on the hilltops around us, and dusk began to settle in. We looked at each other and without a word jumped on the bikes and began to fly down the trail. It was all it was supposed to be. Snatched from the jaws of uncomfortable sleep (it would have been hell out there sleeping on those logs) and delivered to the sweet hopes of a flat piece of earth on which to camp, gallons of fresh water to drink and a mountainous dinner to devour, we pounded the pedals to ring the last bit of light out of the trail during our mad descent.
During that raging downhill we discovered the Rule of Thumb, which is that any stick smaller than your thumb can be snapped by your spokes and is not worth stopping to remove. I swear on my Bons' that this is true.
Upon arrival at the flat Roaring River campground, as the last photons of light were leaving the forest, we turned to urinate on the sign that marked the trail we had just challenged and beaten. Pissing in effigy my brother called it.
We dined triumphantly for many hours, toasting to our good fortune, and eventually pitched the tent on a level patch of ground and fell asleep.
Note: Be sure to take he new Dry Ridge Trail 518. The forest service has apparently moved the trail northward in order to log the forest where the old trail once lay. We have tried to hack the erroneous sign down, to carve at it with Swiss army knives, and have covered the path with logs to keep people from mistakenly deciding to follow it. Your dream trail is a half mile ahead.
Papers by Michael Orendurff
Clinical Biomechanics, 2014
Background-Stiffness of an ankle-foot orthosis plays an important role in improving gait in patie... more Background-Stiffness of an ankle-foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing plantarflexion stiffness of an ankle-foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods-Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two plantarflexion stiffness conditions (0.4 Nm/deg and 1.3 Nm/deg) using a stiffnessadjustable experimental ankle-foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings-By increasing the plantarflexion stiffness of the ankle-foot orthosis, peak plantarfexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation-It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle-foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.
Journal of Foot and Ankle Research, 2008
Foot & Ankle International
Immobilization to limit muscle activity is a common therapeutic and posttreatment event. There ar... more Immobilization to limit muscle activity is a common therapeutic and posttreatment event. There are potential time and resource savings if a prefabricated boot can replace a custom applied cast. The purpose of this study was to determine if muscle activity reduction is similar using a fiberglass cast versus a prefabricated (Aircast FoamWalker) boot. Surface EMG data were recorded from the gastrocnemius, soleus, and peroneals of 12 normal adults while walking barefoot, in a fiberglass cast with a cast shoe (cast), and while wearing an Aircast FoamWalker (boot). Subjects walked at their self-selected speed for 10 trials in each condition, and the order of barefoot, cast, and boot was randomly assigned. The data were rectified, integrated across stance phase and normalized to a percent of each subject's barefoot mean integrated EMG (iEMG) value. For each muscle, a linear mixed-effects statistical model (subject by trial by condition) was utilized to determine if iEMG activity levels...
The American Journal of Sports Medicine, 2007
Clinical Biomechanics, 2014
Background: Energy storage and return feet are designed for active amputees. However, little is k... more Background: Energy storage and return feet are designed for active amputees. However, little is known about the socket reaction moments in transtibial prostheses with energy storage and return feet. The aim of this study was to investigate the effect of alignment changes on the socket reaction moments during gait while using the energy storage and return feet. Methods: A Smart Pyramid™ was used to measure the socket reaction moments in 10 subjects with transtibial prostheses while walking under 25 alignment conditions, including a nominal alignment (as defined by conventional clinical methods), as well as angle malalignments of 2°, 4°and 6°(flexion, extension, abduction, and adduction) and translation malalignments of 5 mm, 10 mm and 15 mm (anterior, posterior, lateral, and medial) referenced from the nominal alignment. The socket reaction moments of the nominal alignment were compared with each malalignment. Findings: Both coronal and sagittal alignment changes demonstrated systematic effects on the socket reaction moments. In the sagittal plane, angle and translation alignment changes demonstrated significant differences (P b 0.05) in the minimum moment, the moment at 45% of stance and the maximum moment for some comparisons. In the coronal plane, angle and translation alignment changes demonstrated significant differences (P b 0.05) in the moment at 30% and 75% of stance for all comparisons. Interpretation: The alignment may have systematic effects on the socket reaction moments in transtibial prostheses with energy storage and return feet. The socket reaction moments could potentially be a useful biomechanical parameter to evaluate the alignment of the transtibial prostheses.
Journal of Biomechanics, 2014
The alignment of a lower limb prosthesis affects the way load is transferred to the residual limb... more The alignment of a lower limb prosthesis affects the way load is transferred to the residual limb through the socket, and this load is critically important for the comfort and function of the prosthesis. Both magnitude and duration of the moment are important factors that may affect the residual limb health. Moment impulse is a well-accepted measurement that incorporates both factors via moment-time integrals. The aim of this study was to investigate the effect of alignment changes on the socket reaction moment impulse in transtibial prostheses. Ten amputees with transtibial prostheses participated in this study. The socket reaction moment impulse was measured at a self-selected walking speed using a Smart Pyramid™ in 25 alignment conditions, including a nominal alignment (clinically aligned by a prosthetist), as well as angle malalignments of 21, 41 and 61 (abduction, adduction, extension and flexion) and translation malalignments of 5 mm, 10 mm and 15 mm (lateral, medial, anterior and posterior). The socket reaction moment impulse of the nominal alignment was compared for each condition. The relationship between the alignment and the socket reaction moment impulse was clearly observed in the coronal angle, coronal translation and sagittal translation alignment changes. However, this relationship was not evident in the sagittal angle alignment changes. The results of this study suggested that the socket reaction moment impulse could potentially serve as a valuable parameter to assist the alignment tuning process for transtibial prostheses. Further study is needed to investigate the influence of the socket reaction moment impulse on the residual limb health.
Gait & Posture, 2005
Individuals with neuromuscular conditions may develop muscle contractures that limit joint motion... more Individuals with neuromuscular conditions may develop muscle contractures that limit joint motion. Decreased muscle length is clinically obvious, but deviations in other functional characteristics of muscle, such as underlying weakness or decreased shortening velocity are more obscure. Therefore, a more comprehensive assessment of muscle characteristics may be required to fully restore function in these individuals. To provide normative comparison data on the force, length and velocity of the triceps surae during walking, 20 adults free from neuromuscular and orthopedic problems were assessed using instrumented gait analysis. Kinematic and kinetic data were used to calculate gastrocnemius and soleus length and velocity, and plantarflexor force during walking. Gastrocnemius length was shortest in early swing and longest in terminal swing and again in midstance. Soleus length was longest throughout the period of single limb stance and was shortest at foot-off. Gastrocnemius shortening velocity was greatest in early swing phase whereas soleus shortening velocity was greatest in pre-swing. Plantarflexor force increased steadily throughout stance phase and peaked in terminal stance at 33.8 ± 3.6 N/kg bodyweight. These data provide target levels on the functional parameters of plantarflexor force, length and velocity in order that therapeutic and surgical interventions could be focused on the deviations observed, and the outcomes of these interventions more objectively assessed.
Gait & Posture, 2002
Nine subjects (12 sides) with cerebral palsy who walked in equnius were evaluated prior to and 1 ... more Nine subjects (12 sides) with cerebral palsy who walked in equnius were evaluated prior to and 1 year after surgical tendo Achilles lengthening. Gastrocnemius and soleus length [Gait Posture, 6 (1997) 9] and plantarflexor force [Gait Posture, 6 (1997) 9; J Biomech, 23 (1990) 495] were calculated. The length of the gastrocnemius and soleus increased significantly (P B 0.01) following the intervention. Force output of the triceps surae during push-off increased significantly (13.95 N/kg body weight (BW) preop to 30.31 N/kg BW postop; P B0.01). Assessment of the force-length capacity of the triceps surae in candidates for tendo Achilles lengthenings may identify individuals at risk of residual weakness and iatrogenic crouch.
Pediatric physical therapy : the official publication of the Section on Pediatrics of the American Physical Therapy Association, 2016
To examine the effect of ankle-foot orthoses (AFO) on walking activity in children with cerebral ... more To examine the effect of ankle-foot orthoses (AFO) on walking activity in children with cerebral palsy (CP). We used a randomized cross-over design with 11 children with bilateral CP, mean age 4.3 years. Subjects were randomized to current AFO-ON or AFO-OFF for 2 weeks and then crossed over. Walking activity (average total steps/day), intensity, and stride rate curves were collected via an ankle accelerometer. Group effects were examined with the Wilcoxon signed-rank test and within-subject effects examined for more than 1 standard deviation change. No significant group difference was found in average total daily step count between treatment conditions (P = .48). For the AFO-ON condition, 2 subjects (18%) increased total steps/day; 4 (36%) increased walking time; 2 (18%) had more strides at a rate of more than 30 strides/min; and 2 (18%) reached higher peak intensity. Clinically prescribed AFO/footwear did not consistently enhance walking activity levels or intensity. Larger studies...
Medicine & Science in Sports & Exercise, 1994
Medicine & Science in Sports & Exercise, 1993
Medicine & Science in Sports & Exercise, 1999
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 1994
Medicine & Science in Sports & Exercise, 1999
Medicine & Science in Sports & Exercise, 1996
Medicine & Science in Sports & Exercise, 2009
"No, I don't think this is it." My brother said while peering through the trees in the directio... more "No, I don't think this is it." My brother said while peering through the trees in the direction of what was once a trail. We had been hopping logs for an hour as the path methodically deteriorated into the faint shadow of a bad memory we were now trying to detect from the forest in general. The sun had just slid down behind the hills and it would be dark in another hour. Our water was low. This was a fitting end to a tour that had not gone entirely well.
We had been circling the Roaring River drainage for three days, first on Abbot road, then on forest road 240 (seven flats until a hidden piece of glass was discovered deeply imbedded in the tire) to the start of the Serene Lake trail at Fraiser turnaround. It was late August and hot as hell. The trail was only slightly rough, and upon arrival, Serene Lake looked welcoming. Welcoming, until we noticed the yellow jackets were out in full force, a hive about every twenty feet around the lake. Never the less, we decided to chance a swim. In one fateful instant, on a rock on the shore, my brother received a dreaded injury. For the next five hours he would nurse a swelling sting on the second most sensitive region of the body. He said he couldn't sit straight on his bike because his ass had become lop-sided. The insect had apparently been studying anatomy and chose the flesh covering the ischial tuberosity (look it up) as the sight to inflict the most damage to a cyclist. We struggled up from the lake, the lake which my brother had re-named many times over by now, to the junction with the Grouse Point trail #517 and began heading north along the even grade.
After an hour of scraping through overgrown rhododendrons, and passing Grouse Point for which the trail is named, we came to what we thought was our salvation - the downhill section of the Dry Ridge trail #518, eyed weeks earlier on a map, from the comfort of a futon couch. How I longed to be on that couch at that very moment, as my brother peered through the trees, his eyes searching in vain for the extinct trail.
On the map it had looked like a straight-shot 3000 foot downhill with raging switchbacks and hairpin corners descending to the Roaring River campground. Total bliss. But our bliss was ignorant. We expected the forest service to be able to maintain a trail that they themselves said existed, and to sign it with some competency, but this was more than could be expected of this usually fine institution.
Now, with darkness looming, my brother was shifting his head from side to side, leaning at a grotesque angle that favored his left cheek, attempting to see past the trees.
"There's a clearing up there. Maybe it's a campground." His hopefulness was discouraging.
I turned to look back the way we had come, reviewing the trail in my mind and how much work it would be to go back up the last two miles. "Lets get the map," I moaned for the fourth or fifth time. Malcolm dragged it out of his handlebar bag, and I peeled back the map's dog-eared corners, going cross-eyed in microscopic study of the frequently cursed document. "This should be here." I said, pointing to a spot on the map worn from finger pointing.
"Definitely a clearing." He said, looking again downhill. He wasn't listening to me.
"What?"
Malcolm threw his bike down and began to walk over the logs, crackling on the thinner sticks that littered the ground. A clearing did appear, and then a logging road, a road that was nowhere near the trail on which we were supposed to be riding. We had been led astray.
Deciding that we knew where we were, the one choice with only moderate insanity was to follow the road to where we could bush-whack toward where we thought the real trail was. The feeling of impending doom rose in my stomach as we returned to get the bikes. We rode warily down the logging road, braking constantly and peering about. If we were wrong, it would be a long way back up.
On a corner that seemed to be the closest to our trail, we paced back and forth, setting our compass. Finally a bearing was decided on and we struck out across the most gnarly mound of blowdown intricately laced with thriving vine maples and patrolled by hundreds of yellow jackets. Every forest gnome reached out to grab our wheels, impale sticks through our frames, scratch our faces, legs and hands. It was a pleasant mountain bike drag-through-the-woods. The fear of being completely wrong in our hypothesis was drying my mouth like a spoonful of raw oatmeal.
We wheezed and pulled and cursed until suddenly the trail appeared. The right trail, a weaving, smooth and curvaceous trail, well maintained and without logs and only a few sticks lying in wait. A trail right out of my living room. The trail of safe, futon dreams –here it was.
The last of the suns rays disappeared on the hilltops around us, and dusk began to settle in. We looked at each other and without a word jumped on the bikes and began to fly down the trail. It was all it was supposed to be. Snatched from the jaws of uncomfortable sleep (it would have been hell out there sleeping on those logs) and delivered to the sweet hopes of a flat piece of earth on which to camp, gallons of fresh water to drink and a mountainous dinner to devour, we pounded the pedals to ring the last bit of light out of the trail during our mad descent.
During that raging downhill we discovered the Rule of Thumb, which is that any stick smaller than your thumb can be snapped by your spokes and is not worth stopping to remove. I swear on my Bons' that this is true.
Upon arrival at the flat Roaring River campground, as the last photons of light were leaving the forest, we turned to urinate on the sign that marked the trail we had just challenged and beaten. Pissing in effigy my brother called it.
We dined triumphantly for many hours, toasting to our good fortune, and eventually pitched the tent on a level patch of ground and fell asleep.
Note: Be sure to take he new Dry Ridge Trail 518. The forest service has apparently moved the trail northward in order to log the forest where the old trail once lay. We have tried to hack the erroneous sign down, to carve at it with Swiss army knives, and have covered the path with logs to keep people from mistakenly deciding to follow it. Your dream trail is a half mile ahead.
Clinical Biomechanics, 2014
Background-Stiffness of an ankle-foot orthosis plays an important role in improving gait in patie... more Background-Stiffness of an ankle-foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing plantarflexion stiffness of an ankle-foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait. Methods-Gait data were collected in 5 subjects with stroke at a self-selected walking speed under two plantarflexion stiffness conditions (0.4 Nm/deg and 1.3 Nm/deg) using a stiffnessadjustable experimental ankle-foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings-By increasing the plantarflexion stiffness of the ankle-foot orthosis, peak plantarfexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active plantarflexion, while the other three subjects could actively plantarflex their ankle joint. Interpretation-It was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle-foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.
Journal of Foot and Ankle Research, 2008
Foot & Ankle International
Immobilization to limit muscle activity is a common therapeutic and posttreatment event. There ar... more Immobilization to limit muscle activity is a common therapeutic and posttreatment event. There are potential time and resource savings if a prefabricated boot can replace a custom applied cast. The purpose of this study was to determine if muscle activity reduction is similar using a fiberglass cast versus a prefabricated (Aircast FoamWalker) boot. Surface EMG data were recorded from the gastrocnemius, soleus, and peroneals of 12 normal adults while walking barefoot, in a fiberglass cast with a cast shoe (cast), and while wearing an Aircast FoamWalker (boot). Subjects walked at their self-selected speed for 10 trials in each condition, and the order of barefoot, cast, and boot was randomly assigned. The data were rectified, integrated across stance phase and normalized to a percent of each subject's barefoot mean integrated EMG (iEMG) value. For each muscle, a linear mixed-effects statistical model (subject by trial by condition) was utilized to determine if iEMG activity levels...
The American Journal of Sports Medicine, 2007
Clinical Biomechanics, 2014
Background: Energy storage and return feet are designed for active amputees. However, little is k... more Background: Energy storage and return feet are designed for active amputees. However, little is known about the socket reaction moments in transtibial prostheses with energy storage and return feet. The aim of this study was to investigate the effect of alignment changes on the socket reaction moments during gait while using the energy storage and return feet. Methods: A Smart Pyramid™ was used to measure the socket reaction moments in 10 subjects with transtibial prostheses while walking under 25 alignment conditions, including a nominal alignment (as defined by conventional clinical methods), as well as angle malalignments of 2°, 4°and 6°(flexion, extension, abduction, and adduction) and translation malalignments of 5 mm, 10 mm and 15 mm (anterior, posterior, lateral, and medial) referenced from the nominal alignment. The socket reaction moments of the nominal alignment were compared with each malalignment. Findings: Both coronal and sagittal alignment changes demonstrated systematic effects on the socket reaction moments. In the sagittal plane, angle and translation alignment changes demonstrated significant differences (P b 0.05) in the minimum moment, the moment at 45% of stance and the maximum moment for some comparisons. In the coronal plane, angle and translation alignment changes demonstrated significant differences (P b 0.05) in the moment at 30% and 75% of stance for all comparisons. Interpretation: The alignment may have systematic effects on the socket reaction moments in transtibial prostheses with energy storage and return feet. The socket reaction moments could potentially be a useful biomechanical parameter to evaluate the alignment of the transtibial prostheses.
Journal of Biomechanics, 2014
The alignment of a lower limb prosthesis affects the way load is transferred to the residual limb... more The alignment of a lower limb prosthesis affects the way load is transferred to the residual limb through the socket, and this load is critically important for the comfort and function of the prosthesis. Both magnitude and duration of the moment are important factors that may affect the residual limb health. Moment impulse is a well-accepted measurement that incorporates both factors via moment-time integrals. The aim of this study was to investigate the effect of alignment changes on the socket reaction moment impulse in transtibial prostheses. Ten amputees with transtibial prostheses participated in this study. The socket reaction moment impulse was measured at a self-selected walking speed using a Smart Pyramid™ in 25 alignment conditions, including a nominal alignment (clinically aligned by a prosthetist), as well as angle malalignments of 21, 41 and 61 (abduction, adduction, extension and flexion) and translation malalignments of 5 mm, 10 mm and 15 mm (lateral, medial, anterior and posterior). The socket reaction moment impulse of the nominal alignment was compared for each condition. The relationship between the alignment and the socket reaction moment impulse was clearly observed in the coronal angle, coronal translation and sagittal translation alignment changes. However, this relationship was not evident in the sagittal angle alignment changes. The results of this study suggested that the socket reaction moment impulse could potentially serve as a valuable parameter to assist the alignment tuning process for transtibial prostheses. Further study is needed to investigate the influence of the socket reaction moment impulse on the residual limb health.
Gait & Posture, 2005
Individuals with neuromuscular conditions may develop muscle contractures that limit joint motion... more Individuals with neuromuscular conditions may develop muscle contractures that limit joint motion. Decreased muscle length is clinically obvious, but deviations in other functional characteristics of muscle, such as underlying weakness or decreased shortening velocity are more obscure. Therefore, a more comprehensive assessment of muscle characteristics may be required to fully restore function in these individuals. To provide normative comparison data on the force, length and velocity of the triceps surae during walking, 20 adults free from neuromuscular and orthopedic problems were assessed using instrumented gait analysis. Kinematic and kinetic data were used to calculate gastrocnemius and soleus length and velocity, and plantarflexor force during walking. Gastrocnemius length was shortest in early swing and longest in terminal swing and again in midstance. Soleus length was longest throughout the period of single limb stance and was shortest at foot-off. Gastrocnemius shortening velocity was greatest in early swing phase whereas soleus shortening velocity was greatest in pre-swing. Plantarflexor force increased steadily throughout stance phase and peaked in terminal stance at 33.8 ± 3.6 N/kg bodyweight. These data provide target levels on the functional parameters of plantarflexor force, length and velocity in order that therapeutic and surgical interventions could be focused on the deviations observed, and the outcomes of these interventions more objectively assessed.
Gait & Posture, 2002
Nine subjects (12 sides) with cerebral palsy who walked in equnius were evaluated prior to and 1 ... more Nine subjects (12 sides) with cerebral palsy who walked in equnius were evaluated prior to and 1 year after surgical tendo Achilles lengthening. Gastrocnemius and soleus length [Gait Posture, 6 (1997) 9] and plantarflexor force [Gait Posture, 6 (1997) 9; J Biomech, 23 (1990) 495] were calculated. The length of the gastrocnemius and soleus increased significantly (P B 0.01) following the intervention. Force output of the triceps surae during push-off increased significantly (13.95 N/kg body weight (BW) preop to 30.31 N/kg BW postop; P B0.01). Assessment of the force-length capacity of the triceps surae in candidates for tendo Achilles lengthenings may identify individuals at risk of residual weakness and iatrogenic crouch.
Pediatric physical therapy : the official publication of the Section on Pediatrics of the American Physical Therapy Association, 2016
To examine the effect of ankle-foot orthoses (AFO) on walking activity in children with cerebral ... more To examine the effect of ankle-foot orthoses (AFO) on walking activity in children with cerebral palsy (CP). We used a randomized cross-over design with 11 children with bilateral CP, mean age 4.3 years. Subjects were randomized to current AFO-ON or AFO-OFF for 2 weeks and then crossed over. Walking activity (average total steps/day), intensity, and stride rate curves were collected via an ankle accelerometer. Group effects were examined with the Wilcoxon signed-rank test and within-subject effects examined for more than 1 standard deviation change. No significant group difference was found in average total daily step count between treatment conditions (P = .48). For the AFO-ON condition, 2 subjects (18%) increased total steps/day; 4 (36%) increased walking time; 2 (18%) had more strides at a rate of more than 30 strides/min; and 2 (18%) reached higher peak intensity. Clinically prescribed AFO/footwear did not consistently enhance walking activity levels or intensity. Larger studies...
Medicine & Science in Sports & Exercise, 1994
Medicine & Science in Sports & Exercise, 1993
Medicine & Science in Sports & Exercise, 1999
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 1994
Medicine & Science in Sports & Exercise, 1999
Medicine & Science in Sports & Exercise, 1996
Medicine & Science in Sports & Exercise, 2009
JPO Journal of Prosthetics and Orthotics, 2013