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Biomedical subjects

C A Greig

Publications and source records attributed to C A Greig.

11 recordsLinked to original sources
PubMed2004

Physical fitness training for stroke patients.

BACKGROUND: Stroke patients have impaired physical fitness and this may exacerbate their disability. It is not known whether improving physical fitness after stroke reduces disability. OBJECTIVES: The primary aims of the review were to establish whether physical fitness training reduces death, dependence and disability after stroke. The secondary aims of the review included an investigation of the effects of fitness training on secondary outcome measures (including, physical fitness, mobility, physical function, health and quality of life, mood and the incidence of adverse events). SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (June 2003). In addition, the following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2002 Issue 4), MEDLINE (1966 to December 2002), EMBASE (1980 to December 2002), CINAHL (1982 to December 2002), SPORTDiscus (1949 to December 2002), Science Citation Index Expanded (1981 to December 2002), Web of Science Proceedings (1982 to December 2002), Physiotherapy Evidence Database (December 2002), REHABDATA (1956 to December 2002) and Index to UK Theses (1970 to December 2002). We hand searched relevant journals and conference proceedings and screened reference lists. To identify unpublished and ongoing trials we searched trials directories and contacted experts in the field. SELECTION CRITERIA: Randomised controlled trials were included when an intervention represented a clear attempt to improve either muscle strength and/or cardiorespiratory fitness, and whose control groups comprised either usual care or a non-exercise intervention. DATA COLLECTION AND ANALYSIS: Data from eligible studies were independently extracted by two reviewers. The primary outcome measures were death, disability and dependence. The lack of common outcome measures prevented some of the intended analysis. MAIN RESULTS: A total of twelve trials were included in the review. No trials reported death and dependence data. Two small trials reporting disability showed no evidence of benefit. The remaining available secondary outcome data suggest that cardiorespiratory training improves walking ability (mobility). Observed benefits appear to be associated with specific or 'task-related' training. REVIEWER'S CONCLUSIONS: There are few data available to guide clinical practice at present with regard to fitness training interventions after stroke. More general research is needed to explore the efficacy and feasibility of training, particularly soon after stroke. In addition more specific studies are required to explore the effect of content and type of training. Further research will require careful planning to address a number of issues peculiar to this type of intervention.

Exercise Therapy↗
PubMed1995

Effects of resistance training on strength, power, and selected functional abilities of women aged 75 and older.

OBJECTIVE: To determine the effects of 12 weeks of progressive resistance strength training on the isometric strength, explosive power, and selected functional abilities of healthy women aged 75 and over. DESIGN: Subjects were matched for age and habitual physical activity and then randomly assigned into either a control or an exercise group. SETTING: The Muscle Function Laboratory, Royal Free Hospital School of Medicine, London. PARTICIPANTS: Fifty-two healthy women were recruited through local and national newspapers. Five dropped out before and seven (4 exercisers and 3 controls) during the study. Pre- and posttraining measurements were obtained from 20 exercisers (median age 79.5, range 76 to 93 years) and 20 controls (median age 79.5, range 75 to 90 years). INTERVENTIONS: Training comprised one supervised session (1 hour) at the Medical School and two unsupervised home sessions (supported by an exercise tape and booklet) per week for 12 weeks. The training stimulus was three sets of four to eight repetitions of each exercise, using rice bags (1-1.5 kg) or elastic tubing for resistance. The exercises were intended specifically to strengthen the muscles considered relevant for the functional tasks, but were not to mimic the functional measurements. No intervention was prescribed for the controls. MEASUREMENTS: Pre- and posttraining measurements were made for isometric knee extensor strength (IKES), isometric elbow flexor strength (IEFS), handgrip strength (HGS), leg extensor power (LEP), and anthropometric indices (Body impedance analysis, arm muscle circumference, and body weight). Functional ability tests were chair rise, kneel rise, rise from lying on the floor, 118-m self-paced corridor walk, stair climbing, functional reach, stepping up, stepping down, and lifting weights onto a shelf. Pre- and posttraining comparisons were made using analysis of variance or analysis of covariance (using weight as a covariate) for normally distributed continuous data and one-sided Fishers exact test (2 x 2 table) for discontinuous data. RESULTS: Improvements in IKES (mean change 27%, P = .03), IEFS (22%, P = .05), HGS (4%, P = .05), LEP/kg (18%, P = .05) were associated with training, but the improvement in LEP (18%, P = .11) did not reach statistical significance. There was an association between training and a reduction in normal pace kneel rise time (median change 21%, P = .02) and a small improvement in step up height (median 5%, P = .005). The other functional tests did not improve. CONCLUSIONS: Progressive resistance exercise can produce substantial increases in muscle strength and in power standardized for body weight in healthy, very old women. However, isolated increases in strength and LEP/kg may confer only limited functional benefit in healthy, independent, very old women.

Activities of Daily Living↗
PubMed1994

Exercise studies with elderly volunteers.

The practicalities of conducting exercise studies with elderly and very elderly people have not been well described. In order to help others plan and perform such studies we describe our experience of recruiting volunteers, applying selection criteria, measuring strength, power, cardiorespiratory responses, and potentially related functional abilities. Exclusion criteria are offered, for safety and to characterize subjects as free of disease which might alter their exercise performance. International agreement on these, or similar, criteria would be valuable. The budget must be adequate for prolonged recruitment before a study and for the liberal use of taxis during it. With healthy subjects in their seventies, the coefficients of variation (CV) for repeated measurements of strength and power were: handgrip 3%, isometric knee extension 6%, isometric elbow flexion 6%, and lower limb extensor power 9%. CV for isometric knee extension by healthy subjects in their eighties was 4%. Treadmill ergometry is more time-consuming than with younger subjects. During progressive treadmill tests, the heart rate interpolated to oxygen consumptions of 10 and 15 ml.kg-1.min-1 had CV = 4% and 7%, respectively.

Aged↗
PubMed1994

Strength, power and related functional ability of healthy people aged 65-89 years.

This cross-sectional study was designed to examine the effects of healthy ageing on muscle strength, power, and potentially related functional ability. Subjects were recruited through local and national newspapers and inclusion was based on strict health criteria, by questionnaire. Isometric knee extensor, isometric elbow flexor and handgrip strength, leg extensor power, timed rise from a low chair, lifting a weighted bag on to a surface, and stepping unaided on to boxes of different heights were measured in 50 men and 50 women, evenly distributed over the age range 65-89 years. The differences in isometric strength and leg extensor power over the age range were equivalent to 'losses' of 1-2% per annum and approximately 3 1/2% per annum, respectively. The decline of explosive power was faster than the decline of knee extensor strength in men (p = 0.0001), but not significantly so in women (p = 0.08). Power standardized for body weight influenced chair rise time and step height. Isometric knee extensor strength standardized for body weight influenced chair rise time.

Aged↗
PubMed1993

The quadriceps strength of healthy elderly people remeasured after eight years.

Isometric quadriceps strength was remeasured in 14 healthy survivors of a group of elderly people first studied 8 years previously. There were 4 men (median age 81 years, range 79 to 84) and 10 women (82 years, range 79 to 89). They were selected for their health, not their levels of physical activity. Nevertheless, they were active when first studied and, with 1 exception, had maintained or increased their levels of physical activity. Isometric quadriceps strength was well preserved; the median change in the strength of the stronger quadriceps was only -0.3% per annum (95% confidence interval = -1.4 to +0.8).

Aged↗
PubMed1992

Short-stepping gait in severe heart failure.

BACKGROUND: Patients with severe chronic heart failure seem to take shorter steps than healthy controls when walking on a treadmill and when walking freely along a corridor. In healthy individuals the pattern of walking affects the oxygen cost of exercise, and so this observation might be relevant to the limitation of exercise in heart failure. METHOD: Length of stride was analysed as stride/stature index in 15 controls, 10 patients with moderate heart failure, 10 patients with severe heart failure, and 10 patients with angina, walking at a constant speed/stature index. RESULTS: The stride/stature index was 0.64 in the controls in patients with New York Heart Association (NYHA) class II heart failure, and in patients with angina. It was 0.49 in patients with NYHA class III heart failure. In the patients with heart failure the stride/stature index correlated with exercise capacity determined as peak oxygen consumption VO2max (R = +0.62, p < 0.005). When healthy controls walked in time to a metronome adjusted to decrease their stride/stature index to approximately that seen in severe heart failure steady-state oxygen consumption increased by a mean of 15%. CONCLUSIONS: The length of stride is reduced in severe heart failure, and when healthy controls adopt this gait the oxygen cost of walking is increased. A short-stepping gait may contribute to the limitation of exercise capacity in heart failure.

Aged↗
PubMed1986

Within-breath changes of airway calibre in patients with airflow obstruction by continuous measurement of respiratory impedance.

We bench-tested a commercially available instrument for measuring respiratory impedance (Siregnost FD5: Siemens) and found that resistance (R) and phase changes were accurately recorded in models. In a single human subject, total respiratory resistance (R(l)) was closely comparable to resistance measured by the Mead-Whittenberger technique. The derived continuous variable (R(os)) was similar to R at less than 4 cmH2O . litres-1 . sec, but underestimated R at higher values. Ros was highly correlated with airways resistance by body plethysmography (R(aw)), but with a low slope and high intercept (R(os) = 1.38 + 0.59 R(aw): r = 0.89). Because of turbulence, both in model larynxes and in normal subjects, R(os) tends to rise with increases in flow in either direction. R(os) also tends to fall as lung volume rises, and vice versa, reflecting cyclic changes in airway calibre. We devised indices of expiratory narrowing of airways from the maximum flow-volume loop, and the plethysmographic alveolar pressure-flow loop, and compared them with the slope of the relation between R(os) and lung volume during tidal breathing, in nine normal subjects and 16 patients with airflow obstruction. Twelve of the 16 patients, all with abnormal flow-volume loops, had high R(os)-volume slopes, demonstrating excessive expiratory narrowing even during tidal breathing. We found no patients with normal inspiratory R(os) together with an abnormal R(os)-volume slope. Thus unstressed inspiratory calibre was never dissociated from airways narrowing on expiration.

Adult↗
PubMed1986

Strength training and power output: transference effects in the human quadriceps muscle.

The effects of strength training of the quadriceps on peak power output during isokinetic cycling has been investigated in group of 17 young healthy volunteers. Subjects trained by lifting near-maximal loads on a leg extension machine for 12 weeks. Measurements of maximal voluntary isometric force were made at 2-3 week intervals and a continual record was kept of the weights lifted in training. Peak power output was measured at 110 rev min-1 and at either 70 or 80 rev min-1 before and after the 12 week training period. Measurements of maximum oxygen uptake (VO2max) were made on 12 subjects before and after training. The greatest change was in the weights lifted in training which increased by 160-200%. This was accompanied by a much smaller increase in maximum isometric force (3-20%). There was no significant change in peak power output at either speed. The VO2max remained unchanged with training. The role of task specificity in training is discussed in relation to training regimes for power athletes and for rehabilitation of patients with muscle weakness.

Adolescent↗
PubMedDate not supplied

Muscle function of women aged 65-89 years meeting two sets of health criteria.

This study compared the isometric strength, leg extensor power, and some potentially related functional abilities of elderly women selected for exercise studies according to two sets of readily applicable exclusion criteria. The health status criteria ("healthy" and "medically stable") differed principally in respect to duration of freedom from diagnosed or symptomatic disease, medication taken and Body Mass Index. Fifty "healthy" women and fifty "medically stable" women, aged 65 to 89 and evenly distributed over the age range, were recruited through local and national newspapers. There was no significant difference between the two health groups in strength or power. However, the women in the "medically stable" group were heavier and had more difficulty in rising from a chair. The strength of the relationships between strength, power and kneel rise time were very dependent on body weight for the "medically stable" women but not for the "healthy" women. The health criteria used to classify elderly subjects must be clearly specified so that there may be easier interpretation of results from future studies. This is especially true in studies where body weight might be important.

Age Factors↗