Biomedical subjects

W Gilleard

Publications and source records attributed to W Gilleard.

5 recordsLinked to original sources

PubMed2006

Effect of obesity on posture and hip joint moments during a standing task, and trunk forward flexion motion.

OBJECTIVE: Effects of obesity on trunk forward flexion motion in sitting and standing, and postural adaptations and hip joint moment for a standing work task. DESIGN: Cross-sectional comparison of obese and normal weight groups. SUBJECTS: Ten obese subjects (waist girth 121.2+/-16.8 cm, body mass index (BMI) 38.9+/-6.6 kg m(-2)) and 10 age- and height-matched normal weight subjects (waist girth 79.6+/-6.4 cm, BMI 21.7+/-1.5 kg m(-2)). METHODS: Trunk motion during seated and standing forward flexion, and trunk posture, hip joint moment and hip-to-bench distance during a simulated standing work task were recorded. RESULTS: Forward flexion motion of the thoracic segment and thoracolumbar spine was decreased for the obese group with no change in pelvic segment and hip joint motion. Obese subjects showed a more flexed trunk posture and increased hip joint moment and hip-to-bench distance for a simulated standing work task. CONCLUSIONS: Decreased range of forward flexion motion, differing effects within the trunk, altered posture during a standing work task and concomitant increases in hip joint moment give insight into the aetiology of functional decrements and musculoskeletal pain seen in obesity.

Adult↗

PubMed2005

The use of lumbar spinal stabilization techniques during the performance of abdominal strengthening exercise variations.

AIM: The lumbar spinal stabilization techniques in abdominal hollowing and bracing are known to facilitate the level of activity in the muscles transversus abdominis and obliquus internus (TA/OI). The relative timing of activation and the effect of combination with other tasks are currently unknown. The objective of this study was to determine whether the performance of abdominal hollowing and bracing could promote the voluntary preferential recruitment of TA/OI muscles when performed prior to abdominal strengthening exercise variations. METHODS: The trunk muscles TA/OI, rectus abdominis and obliquus externus were investigated using surface EMG. A pressure transducer under the lumbar spine detected spinal movement. Eighteen male subjects performed a series of 4 abdominal strengthening exercise variations. Pressure cuff and electromyographic onset times were collected and analyzed. RESULTS: TA/OI muscle site was recruited significantly earlier than the upper rectus abdominis site for the hollow with curl exercise. The TA/OI site was also ranked as first activated site in the majority of subjects during exercises where stabilization techniques of hollowing and bracing were used. CONCLUSIONS: Abdominal hollowing was an effective method for selective preferential voluntary recruitment of TA/OI site prior to the performance of the curl type abdominal strengthening exercise variation. The other variations brace with curl and hold and hollow with rotation also tend to recruit TA/OI site first, however the timing was not significantly different.

Abdominal Muscles↗

PubMed1999

Three-dimensional kinematics of the forefoot, rearfoot, and leg without the function of tibialis posterior in comparison with normals during stance phase of walking.

BACKGROUND: Many studies have shown that lack of functional activity of tibialis posterior leads to changes in the longitudinal arch and affects the motion of the foot. A quantitative description of the affects on the motion of the foot in detail has not been reported. OBJECTIVE: To describe three-dimensional motion of the leg, rearfoot and forefoot with tibialis posterior dysfunction during stance phase of walking in comparison with normals. This study compared one case without the function of tibialis posterior with the ensemble average of 10 normals (five males, five females). METHODS: Subjects with 10, 12 mm retroreflective markers placed on their right leg, rearfoot and forefoot, performed five trials of walking at self-selected speed on a 10 m walkway. A four-camera three-dimensional motion analysis system and a synchronized force platform were used to record three-dimensional motions of the segments and force variables during stance phase of walking. RESULTS: The patterns and range of motion of the rearfoot relative to the leg, and the forefoot relative to the rearfoot demonstrated some differences between the tibialis posterior dysfunction case and normals. Most of the major differences occurred from just prior to heel-off through to toe-off, the period when a stable arch would be required. CONCLUSION: The observed differences in the three-dimensional foot motions of the tibialis posterior dysfunction case compared with normals during walking were consistent with the expected mechanical consequences of a foot without the function of tibialis posterior. The one exception was the inversion of the rearfoot which remained normal. RELEVANCE: Tibialis posterior dysfunction has been recognized as one of the significant impairments of the musculoskeletal system which affects normal walking. Dynamic investigation adds an understanding of how the muscle controls the foot during walking which is essential information for the diagnosis and the adjustment of treatment and rehabilitation for a tibialis posterior dysfunction case.

Adult↗

PubMed1998

The effect of patellar taping on the onset of vastus medialis obliquus and vastus lateralis muscle activity in persons with patellofemoral pain.

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the effect of patellar taping on the onset of activity of the vastus medialis obliquus muscle (VMO) and the vastus lateralis muscle (VL). SUBJECTS AND METHODS: Fourteen female subjects with patellar pain walked up and down stairs in two conditions: (1) with the patellofemoral joint of the painful lower extremity taped so that the pain was reduced by at least 50% on a pain provocation test and (2) without patellar taping. RESULTS: When the patellofemoral joint was not taped, there was no difference in the onset of activity between the VMO and the VL during the step-up and step-down tasks. During the step-up task, the onset of VMO activity occurred earlier with taping but there was no change in the onset of VL activity with taping. During the step-down task, the onset of VMO activity occurred earlier and the onset of VL activity was delayed with taping. When the patellofemoral joint was taped, the VMO was activated earlier than the VL during the step-up and step-down tasks. CONCLUSION AND DISCUSSION: Taping of the patellofemoral joint in the manner used in this study changed the timing of VMO and VL activity in subjects with patellofemoral pain during step-up and step-down tasks. The earlier activation of the VMO may alter the movement of the patella, and further research is needed to determine whether this occurs and whether it is beneficial.

Adolescent↗

PubMed1991

Transition from slow to ballistic movement: development of triphasic electromyogram patterns.

The purpose of this investigation was to determine how the triphasic electromyogram (EMG) pattern of muscle activation developed from the agonist muscle only pattern as movement time (tmov) decreased. Six adult women produced a series of 30 degrees elbow extension movements in the horizontal plane at speeds ranging from ballistic (less than 400-ms tmov) to very slow (greater than 800-ms tmov). Surface EMG from triceps brachii (agonist) and biceps brachii (antagonist) muscles were recorded, together with elbow angle, on a microcomputer. The results showed that triphasic EMG patterns developed systematically as tmov decreased from 1000 ms to less than 200 ms. In trials with very long tmov, many elbow extension movements were produced by a single continuous activation of the agonist triceps brachii muscle. As tmov decreased however, agonist activation became predominantly burst-like and other components of the triphasic EMG pattern [activation of the antagonist (Ant) and second agonist activation (Ag2)] began to appear. At the fastest movement speeds, triphasic EMG patterns (Ag1-Ant-Ag2, Ag1 being first activation of agonist muscle) were always present. This data indicated that the triphasic pattern of muscle activation was not switched on when a particular tmov was achieved. Rather, each component systematically developed until all were present, as distinctive bursts of activity, in most trials with tmov less than 400 ms.

Adolescent↗