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Biomedical subjects

E J Bassey

Publications and source records attributed to E J Bassey.

At least 19 recordsLinked to original sources
PubMed1997

Relations between compressive axial forces in an instrumented massive femoral implant, ground reaction forces, and integrated electromyographs from vastus lateralis during various 'osteogenic' exercises.

A subject, who had undergone surgery to replace one hip joint and the proximal half of the femur with an instrumented titanium implant, performed brief exercises whilst simultaneous measurements were made of compressive axial force in the implant using short-range wireless telemetry, ground reactions using a Kistler force plate, and electromyographic activity of the vastus lateralis (VL) and erector spinae (ES) muscles using surface electrodes. Recordings were made barefoot and wearing 'trainers'. The exercises (slow jumping in counter movement style, fast continuous jumping, and jogging on the spot) have been found effective in controlled interventions for increasing bone mineral density in women. The implant forces were 250-400% BW. The values were about twice the magnitude of the ground reaction forces and significantly correlated with them for both peak force and its rate of rise but their relative magnitudes varied depending on mode of activity (jumping or jogging). Implant forces were significantly related to the muscle activity; in multiple regression analysis implant forces during take off from slow jumps VL contributed significantly in addition to the ground reaction (98% total explained variance). There was more activity in VL during jumping than jogging for the same implant force which may explain why jumping appears to be more osteogenic than jogging for the femur. For the same ground reaction, wearing trainers increased both the magnitude of the compressive loading of the femur and its rate of rise.

Analysis of Variance↗
PubMed1996

Lack of variation in muscle strength with menstrual status in healthy women aged 45-54 years: data from a national survey.

Isometric handgrip, quadriceps muscle strength and leg extensor power were assessed as part of a large representative survey of adult men and women in England. The gender ratios for these muscle strength measurements did not differ across age groups, which ranged from 25 to 65 years. Data from a subsample of women who were aged between 45 and 54 years and free of major health problems or current gynaecological problems (n = 299) and were analysed to see if there were differences in the muscle measurements according to reported menstrual status. Analysis of variance was used to compare four subgroups of women as follows: those who were still menstruating regularly (n = 89), those who had stopped altogether (n = 92), those who were irregular (n = 33) and those on hormone replacement therapy (n = 15). No significant differences were found between these subgroups in any of the three muscle measurements, body mass, fat-free mass (derived from four skinfolds), body mass index, or customary activity levels. There was a significant age difference of 2 years between two subgroups. After having controlled for this, using analysis of covariance, the outcome was not changed. These women were also compared with men in the same age range; the women had about 60% of the strength of the men and a highly significant difference remained after controlling for fat-free mass in all subgroups. No evidence was found for an ergogenic effect of the high oestrogen status conferred by natural menstruation or hormone replacement therapy.

Analysis of Variance↗
PubMed1996

Effects of hormone replacement therapy on muscle performance and balance in post-menopausal women.

1. A randomized controlled trial of the effect of oral hormone replacement therapy plus calcium compared with calcium alone on balance, muscle performance and falls was conducted over 48 weeks in 116 post-menopausal women (aged 45-70 years), all of whom had suffered a distal radial fracture during the previous 3 months. Treatment was with Prempak C or Premarin 0.625 mg in the test group with 1 g calcium daily (Sandocal) in both groups. Measurements were made of balance, assessed as sway, leg extensor power and self-paced walking speed, at 12-week intervals over 24 weeks. Hand grip strength was measured every 12 weeks for 48 weeks, and falls in the preceding 12 weeks were recorded at each visit. 2. There was no relation between initial levels of oestradiol and any other variable assessed, except body mass. Levels of follicle-stimulating hormone in the test group were in the premenopausal range. There was no significant change attributable to hormone replacement therapy at any time point in any of the outcome variables. The only significant difference was an increase of 4.2% (95% confidence interval 0.7-7.6%) in leg extensor power in the control group (calcium alone) compared with the group treated with hormone replacement therapy. 3. Of the total group, 37% fell again during the year, with three patients suffering a further fracture. Frequent fallers swayed significantly more often than the others, but there was no evidence that their muscle strength was poorer or that the group treated with hormone replacement therapy fell less frequently. 4. Hormone replacement therapy did not increase muscle performance, improve balance or reduce falls over a year in middle-aged women.

Accidental Falls↗
PubMed1996

Postexercise heart rates and pulse palpation as a means of determining exercising intensity in an aerobic dance class.

OBJECTIVE: To establish the accuracy of the traditional method of measuring the intensity of exercise in aerobic dance classes, that is, intermittent pulse palpation performed during a brief cessation of activity. METHODS: A short wave telemetry system was used to record heart rates during a class in a group of 12 healthy women aged 26 (SD 6) years. Subjects palpated their pulses for 10 s following high and low intensity exercise [78(8)% and 69(9)% of mean predicted maximum heart rate respectively]. Recorded exercising heart rates, averaged over 60 s preceding pulse palpation [ExHR(rec)], were compared with the recorded postexercise heart rates averaged over the 10 s palpation period [PostExHR(rec)] and with the palpated counts (PalpHR). Differences were assessed using Student's t test and Wilcoxon signed rank test. RESULTS: Differences between ExHR(rec) and PostExHR(rec) following high and low intensity exercise [3(6) beats.min-1 and 5(7) beats.min-1 respectively] were not significant. However, the wide variation between subjects means that a postexercise heart rate is unreliable as a measure of individual exercise intensity. PalpHR was significantly lower than ExHR(rec) (P < 0.01). Every individually palpated count underestimated the exercising heart rate (range 9 to 95 beats.min-1). CONCLUSIONS: While postexercise heart rate adequately represents the exercise heart rate for a group, the individual variation is too wide for this to be a useful measurement.

Adult↗
PubMed1996

Longitudinal weight changes over four years and associated health factors in 629 men and women aged over 65.

OBJECTIVES: (1) To assess changes in body weight longitudinally over 4 years in a representative group of men and women aged over 65 years, living in their own homes. (2) To assess whether initial weight (or weight in proportion to skeletal size) was associated with health 4 years later. (3) To assess whether any changes found in body weight were associated with changes in physical or mental health. (4) To compare the cross-sectional age-related changes in weight found in the initial survey with the longitudinal changes found over 4 years. DESIGN: A large randomised age-stratified survey using a structured questionnaire and measurements of body weight and demispan (for skeletal size), with a 4-year follow-up. SETTING: The survey was conducted in the respondents' own homes. SUBJECTS: 958 subjects age over 65 years, who were recruited from the Nottingham general practitioners' lists, took part in the initial survey; 629 of these subjects completed the second survey 4 years later. RESULTS: (1) The mean 4-year change in body weight was a small but significant loss; in women (n = 385) it was 1.56kg (P <0.001, 95% CI 1.02-2.10) and in men (n = 244) 0.85kg (P = 0.010, 95% CI 0.21-1.49). (2) Initial weight did not predict mortality, new morbidity nor health 4 years later. (3) There were no robust associations between weight change ans either absolute measures of physical health or changes in these measures. (4) The longitudinal change in weight was similar to that predicted by the cross-sectional data. CONCLUSIONS: (1) Ageing, in old age, is associated with loss of body weight, but with a large intra-individual variation. (2) Neither initial body weight nor the change, was associated with mortality or morbidity over 4 years in a large representative sample of old people living in their own homes in a food-rich country.

Age Factors↗
PubMed1995

Weight-bearing exercise and ground reaction forces: a 12-month randomized controlled trial of effects on bone mineral density in healthy postmenopausal women.

The effects of brief daily exercise on bone mineral density (BMD) were assessed in a randomized controlled trial in 44 healthy postmenopausal women using weight-bearing exercise in a regimen adapted from osteogenic protocols reported in animal studies. BMD was assessed masked using dual energy X-ray absorptiometry at 0, 6, and 12 months. The sites assessed were the proximal femur (neck, Ward's triangle, and trochanter) and the lateral spine (L2-3) to assess the effects of the exercise, and the radius (ultradistal and 33% distal) as a marker for systemic effects. The test group was required to perform 50 "heel drops" daily at home (raising the body weight onto the toes and then letting it drop to the floor keeping the knees and hips extended) and to attend a weekly class of mixed exercises, which included some high-impact activity. The control group also attended a weekly exercise class run by the same teacher, which included only low-impact activity, and did flexibility exercises at home daily. The ground reaction forces (as a ratio of body weight) during heel drops were 2.5 to 3.0 N/N, with a rate of rise of 50-100 kN/sec. A patient with an instrumented femoral implant allowed comparison of compressive axial forces in the shaft of the proximal femur with the ground reaction forces, and these appeared to be transmitted undamped to the shaft of the femur. Initial analysis of BMD in the women showed no significant increases after 12 months of exercise at any site in either group, and the groups did not differ significantly from each other in this respect. Proximity to menopause was not associated with rapid bone loss, and in those who were more than 6 years postmenopausal, there was evidence for a maintenance effect of the exercise in the test group. Compliance (83%) and increases in leg extensor power (15%) were similar in both groups, and when they were combined, BMD was maintained at the trochanter but fell significantly at the radius (p < 0.001).

Biomechanical Phenomena↗
PubMed1994

A comparison of the relation between oxygen uptake and heart rate during different styles of aerobic dance and a traditional step test in women.

The oxygen uptake and heart rate in various styles of dance and in a graded step test have been compared in ten healthy women aged [mean (SD)] 34 (5) years. Dance was choreographed into progressively more energetic sequences typical of community classes, and videotaped. Oxygen uptake was assessed using a respirometer carried in a back-pack. Each of the two tests (dance and step) took 15-20 min and measurements were made in randomised balanced order on the same day. The mean oxygen costs of dance ranged from 1.29 l.min-1 for low impact style to 1.83 l.min-1 for high impact style with arm work; mean heart rates were 135 and 174 beats.min-1 respectively. Low impact dance raised heart rates above 60% of predicted maximum and so would provide training; during high impact dance recorded heart rates sometimes exceeded recommended safe limits. The addition of arm work significantly increased heart rates in both high and low impact dance but when oxygen pulses for each style of dance were compared no significant differences attributable to arm work were found. Moreover calculated differences between oxygen uptakes in stepping and dance at the same heart rates (those recorded during dance) were not significant for any of the four styles. Analysis of variance confirmed that neither arm work nor impact contributed significantly to the differences, so there was no evidence that these forms of dance change the normal relation between heart rate and oxygen uptake found in dynamic activities with large muscle groups such as stepping.

Adult↗
PubMed1994

Increase in femoral bone density in young women following high-impact exercise.

Healthy premenopausal women were randomized into control and test groups; both exercised weekly in class and daily at home for a year. The test class did intermittent high-impact exercise; the control class did low-impact exercise. Bone density was assessed blind using dual energy X-ray absorptiometry at the femur (neck, Ward's triangle and trochanter) and at the lumbar spine (antero-posterior L1-4) on entry into the study, and again after 6 months (n = 27) and 12 months (n = 19). At 6 months the test group (n = 14) showed a significant increase of 3.4% in trochanteric bone density (p = 0.01) and this was significantly different from control (p = 0.05). In the second 6 months the control group was crossed over to high-impact exercise and showed a significant increase of 4.1% in trochanteric density (n = 7) while the original group maintained their improvement relative to baseline.

Adult↗
PubMed1994

Changes in bone mineral density associated with dietary-induced loss of body mass in young women.

1. Moderately overweight, premenopausal women were assessed for bone mineral density of the total body, lumbar spine and proximal femur before and after 6 months of modest dietary restriction (minimum 4800 kJ/day). The aim was to evaluate the effect of loss of body mass on bone mineral density. 2. Dietary assessment included two analyses of 3 day weighed food intakes, one before and the other after 4 months of dietary restriction. Energy and calcium intakes were significantly reduced by 27% and 5%, respectively. The change in calcium intake was negatively and significantly related to initial levels of calcium intake. 3. A significant mean loss of 3.4 +/- 3.1 kg in body mass was achieved mainly in the first 3 months of the study; it was accompanied by significant losses at 6 months in bone mineral density in the total body of 0.7% and in the lumbar spine of 0.5%. There were no changes in the femur. 4. The change in bone mineral density in the total body was significantly related to the reduced absolute calcium intake, initial bone mineral density and loss of body mass. The change in bone mineral density in the spine was significantly related to the change in calcium intake. 5. These modest losses could be a threat in women with lower bone mineral density, and indicate the importance of maintaining a high intake of calcium during dietary restriction.

Absorptiometry, Photon↗
PubMed1994

Dietary calcium intake relates to bone mineral density in premenopausal women.

Bone density and Ca intake were assessed in fifty-six healthy premenopausal women, aged 21-47 years. Bone density was measured at the spine (lumbar vertebrae 1-4, anterio-posterior view), the non-dominant femur (neck, Ward's triangle and trochanter) and radius (33% distal and ultradistal) using dual energy X-ray absorptiometry (Lunar DPX-L). The mean values (SD) for bone density (g/cm2) were 1.18 (0.10) at the lumbar spine, 0.81(0.10) at the trochanter and for Ca intake 783 (329) mg. Bone density values were close to published normal values for young women and the Ca intakes were close to the recommended levels for the UK. However, there was a wide range especially in dietary Ca intake, and 27% of the group were at or below 500 mg/d. Correlations between Ca intake and bone density were highly significant at all three femoral sites (neck r 0.41; Ward's triangle r 0.40, P < 0.01; trochanter r 0.47, P < 0.001), significant at the spine (r 0.27, P < 0.05) but not found at the radius. These correlations were independent of body mass. The low levels of Ca intake found in a substantial proportion of this selected group of young women and their association with low femoral bone density are cause for concern.

Absorptiometry, Photon↗
PubMed1993

Normal values for handgrip strength in 920 men and women aged over 65 years, and longitudinal changes over 4 years in 620 survivors.

1. The maximal grip strength of the hand has been measured in a random sample of 359 men and 561 women aged over 65 years living in their own homes. The response rate was 80% from a representative demographic area of the U.K. Measurements were made of body mass, skeletal size (demispan) and grip strength. Grip strength was measured using a custom-built strain-gauged dynamometer. The best of three attempts was taken as definitive. A structured questionnaire was used to obtain information about customary activity, use of handgrip muscles, health and psychological well-being. This was repeated with 620 survivors 4 years later. 2. The results for strength were normally distributed. The right hand was 10% stronger than the left and men had twice the strength of women. Strength was significantly related to skeletal size and in men to body mass. The gender difference was only partly accounted for by skeletal size and women were substantially disadvantaged in terms of their strength/body mass ratio. 3. There was a significant decline in strength with age of 2%/year for men and women. Strength was also significantly related to customary activity, reported use of the hands and psychological and physical health. 4. After 4 years 620 survivors were re-measured. Grip strength had declined by 12% in men and 19% in women and these losses were significantly related to age. A significant decline was also found in reported use, customary activity and health scores, and in women in body mass and psychological health.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Leg extensor power and functional performance in very old men and women.

1. Residents of a chronic care hospital (13 men of mean age 88.5 +/- 6 SD years and 13 women of mean age 86.5 +/- 6 SD years) who had multiple pathologies were assessed for leg extensor capability in several ways. 2. A custom-built rig was used to assess leg extensor power, that is, maximal power output over less than 1 s in a single extension of one leg. Performance measures were obtained by timing chair rises (from a standard chair 0.43 m high), stair climbing (four risers, total height 0.635 m) and a walk (6.1 m). For each measurement the best of several trials were recorded as definitive. 3. Leg extensor power was significantly correlated with all performance measures, but the performance measures were not related to each other except for chair rising and walking speed. 4. Women had significantly less extensor power than men, but their power explained more of the variance in performance, e.g. power accounted for 86% of the variance in walking speed. 5. There was no relation within the group between age and any of the variables measured. 6. Measurement of leg extensor power in frail elderly people may prove useful in focusing effective rehabilitation programmes.

Aged↗
PubMed1990

A new method for measuring power output in a single leg extension: feasibility, reliability and validity.

A method is described for measuring the explosive power of the leg in extension which has been found safe and acceptable for all age groups and levels of physical capability. The extension movement takes 0.25-0.40 s in a push through 0.165 m against a flat pedal. At the end of the push the leg is fully extended. The movement is made seated so that the forces are contained between the buttocks and the foot. The seat position is adjusted for leg length and the push is transmitted by a lever and chain to spin a flywheel. The gearing is such that resistance to the movement remains velocity of the flywheel is measured by an optoswitch and used to calculated the average leg extensor power (LEP) in the push. The reliability of the power measurement was evaluated in 46 subjects ranging in age from 20 to 86 years; they included medical students and geriatric day patients. They were tested on two occasions separated by a week. The maximal values on the first occasion (best of at least five trials) ranged from 30 to 300 W (mean +/- 1 SD = 154 +/- 88 W). There was no significant difference on re-test and the coefficient of variation was 9.4%. In a subgroup of 9 non-naive subjects who were measured by an experienced observer it was 6.3%. As expected, power was lower in women than in men and declined sharply with age. The sex difference was less when the values were expressed as power per body mass; a sharp age-related decline remained.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Torque-velocity relationships for the knee extensors in women in their 3rd and 7th decades.

Maximal isokinetic knee extensor strength was measured as torque in 17 young (mean age +/- SD, 21 +/- 3 years) and 16 elderly (68 +/- 5 years) women at 30 degrees (0.52 rad) before full extension, at angular velocities from 0 to 5.24 rad s-1, in 7 increments of 0.87 rad s-1. The elderly women were significantly weaker than the young women at all angular velocities. The rate of loss of absolute torque with increasing velocity was similar for both age groups, but when torque was standardised as a percentage of the individual's maximum, the elderly group showed a significantly greater rate of loss than the younger group. Quick-release from an isometric effort did not increase the recorded torques at 4.36 rad s-1 compared with the free-running method in either age group. The age differences are compatible with lower ratio of type II to type I fibre are in the older group.

Adult↗