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Biomedical subjects

M I Bullock

Publications and source records attributed to M I Bullock.

7 recordsLinked to original sources
PubMed1994

The influence of ankle sprain injury on muscle activation during hip extension.

The likely influence of a localised injury in a distal joint on the function of proximal muscles is an important consideration in assessment and treatment of musculoskeletal injuries. However, little experimental evidence in humans exists in this area. Accordingly, a controlled study was carried out, in which the function of muscles at the hip was compared between subjects who had suffered previous severe unilateral ankle sprain and matched control subjects. The pattern of activation of the gluteus maximus, the hamstring muscles and the ipsilateral and contralateral erector spinae muscles was monitored through the use of surface electromyography during hip extension from prone lying. Analyses revealed that the pattern of muscle activation in subjects with previous injury differed markedly from normal control subjects, and that changes appeared to occur on both the uninjured and the injured sides of the body. A significant difference between the two groups was the delay in onset of activation of the gluteus maximus in previously injured subjects. The existence of remote changes in muscle function following injury found in this study emphasise the importance of extending assessment beyond the side and site of injury.

Adolescent↗
PubMed1993

Reflex activation of gluteal muscles in walking. An approach to restoration of muscle function for patients with low-back pain.

Gluteal activation and pelvic stability often are decreased in chronic low-back pain sufferers, but the importance of motor control and programming in treatment has not been fully evaluated. This study investigated whether gluteal muscles could be activated more effectively by stimulating the proprioceptive mechanism during walking. Labile support, through wearing "balance shoes," offered facilitation of cerebellovestibular circuits. Electromyographic recordings of gluteus maximus and medius in 15 healthy subjects were made during barefoot and balance shoes walking before and after 1 week of facilitation. Significant increases (P < 0.0002) in gluteal activity and significant decreases (P < 0.01) in time to 75% maximum contraction, demonstrated the value of sensorimotor elicitation of subconscious and automatic responses in muscles often weakened in back pain sufferers.

Adult↗
PubMed1986

Changes in muscle activity during fast, alternating flexion-extension movements of the knee.

The effects of high frequency alternating knee flexion-extension on muscle activity of the quadriceps and hamstring muscle groups has been investigated. Standard loads were used for each subject. The muscle activity in vastus medialis, vastus lateralis, rectus femoris and the lateral hamstrings were recorded by electromyography during increasing velocities. Rectus femoris and hamstrings were found to increase their activities significantly with increasing speed while vastus medialis and vastus lateralis showed no such change. The individual thigh muscles thus differ in function in relation to the velocity of movement.

Adult↗
PubMed1985

Comparison of abilities of preterm and maturely born children at 5 years of age.

This study investigated whether the development of 5 year old preterm born children was appropriate for age and equivalent to or different from their peers who were full term at birth. At the adjusted age of 5 years, the development of 106 children born 5 or more weeks before term was compared with the development of 103 children who were born at term. This latter group of children were matched to the preterm group in sex, year of birth, birthplace, race and residential location. No cerebral palsy children were included in either subject group. The results indicated a significant difference between the two groups. Factors distinguishing the preterm children from their full term peers included small involuntary hand movements, less competent gross motor ability, poorer verbal performance and more variability in behaviour, postural response and balance. A higher than average incidence of minor motor, speech, behaviour and learning problems in early school years is probable.

Child Behavior↗
PubMed1978

Ripcord release capability of female parachutists.

With the growth in popularity of skydiving as a sport has come an associated increase in parachuting accidents, some of them due to failure to deploy the main or reserve parachutes. The absence of appropriate strength data has prompted a study of the pull force capabilities of female parachutists on a ripcord release in varying positions. Pull forces exerted for periods of 0.25, 1, 1.5, 2, and 2.5 s during a 5-s pull are presented in percentile form. A substantial percentage of female parachutists could not exert the maximum ripcord release pull force permitted by the relevant parachute specification. The relatively low level of strength exhibited by the weakest groups of the population emphasizes the need for such basic information in equipment design.

Adult↗