Lis Puggaard

Explosive heavy-resistance training in old and very old adults: changes in rapid muscle force, strength and power

Age‐related decline in muscle power predicts falls, motor impairments and disability. Recent guidelines suggested that training programs should be tailored to maximize muscle power. This study investigated the effects of 12 weeks of explosive‐type heavy‐resistance training (75–80% of 1 repetition maximum) in old (60–65 years, TG60) and very old (80–89 years, TG80) community‐dwelling women. Training was performed with maximal intentional acceleration of the training load during the concentric movement phase. Maximal isometric voluntary muscle strength (MVC), rapid force capacity, assessed as rate of force development (RFD), and impulse, maximal muscle power during a countermovement jump (CMJ) and during unilateral leg extension task (LEP) were evaluated. RFD, impulse and MVC increased by 51%, 42% and 28% in TG80, and by 21%, 18% and 18% in TG60, respectively. CMJ jump height increased by 18% and 10% in TG80 and TG60, respectively, while jump peak power increased in TG60 (5%). Finally, LEP increased 28% in TG80 and 12% in TG60. These findings demonstrate that explosive‐type heavy‐resistance training seems to be safe and well tolerated in healthy women even in the eighth decade of life and elicits adaptive neuromuscular changes in selected physiological variables that are commonly associated with the risk of falls and disability in aged individuals.

Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

Abstract Elderly people (age 75 years; n=48 males and 34 females) were studied in order to elucidate gender differences in elderly subjects on the determinants of muscle power (force and velocity) during a stretch-shortening cycle. All subjects performed three maximal counter-movement vertical jumps using both legs, on a force platform (Kistler 9281 B). The eccentric (Ep) and concentric (Cp) phases of the jumps were analyzed. The Ep was further divided into an acceleration phase (Epacc: from the start of the downward movement to the maximal negative velocity) and deceleration phase (Epdec: from the maximal negative velocity to the end of the downward movement). Jump height for the men was higher than for the women (P < 0.001). During both Epacc and Epdec no significant differences were observed between males and females in force and power generation. However, the men had a higher peak muscle power during the Cp, which may be explained exclusively by the velocity determinant (P < 0.001). No specific gender-related strategy appeared to influence the motor pattern of the movement. The comparable eccentric force generation of the leg extensors in both genders suggests a similar ability to cope with eccentric muscle actions during everyday activities. In contrast, the marked lower capacity for concentric contractions in women may result in an impaired performance, especially in activities where intense and rapid movements are essential, for example when reversing a forward fall. This may be one reason why elderly women are more prone to falls than are elderly men.

Exercise on prescription: a randomized study on the effect of counseling vs counseling and supervised exercise

The aim of this study was to compare short‐ (0–4 months) and long‐term (0–10 months) effects of high‐intensive Exercise on Prescription (EoP) intervention (counseling and supervised exercise) implemented in primary healthcare in a number of Danish counties with a low‐intensive intervention (counseling) using maximal oxygen uptake (VO2max) as the primary outcome. The study was conducted as a randomized trial in 2005–2006 with a high and a low‐intensive group. All the patients referred to the EoP scheme by their GP in the counties of Vejle and Ribe, Denmark, were eligible for the trial. The high‐intensive EoP group received 4 months of group‐based supervised training and attended five motivational counseling sessions. The low‐intensive group only attended four motivational counseling sessions. Three hundred and twenty‐seven patients entered the EoP scheme, and 52 (16%) volunteered for the randomized trial. No short‐ or long‐term differences were found between the high and the low‐intensive groups for VO2max (short‐term 95% CI −1.1; 4.4 mL O2/(kg min), long‐term 95% CI −1.6 to 2.1). The present study did not demonstrate any significant clinical outcome for the high‐intensive EoP intervention as opposed to the low‐intensive intervention.

Reproducibility and relationship of single-joint strength vs multi-joint strength and power in aging individuals

Introduction: Reliable and sensitive muscle strength/power assessments are essential when evaluating age‐related and/or training‐induced changes in maximal strength and power.

Effects of individually tailored physical and daily activities in nursing home residents on activities of daily living, physical performance and physical activity level: a randomized controlled trial.

Background: Nursing home residents are extremely inactive and deterioration in health and an increasing dependence in activities of daily living (ADL) are common. Physical activity and exercise play a major role in the preservation of physical function and quality of life late in life. However, evidence for the benefit of rehabilitation in nursing home residents is conflicting and inconclusive. Objective: To evaluate the effect of an individually tailored intervention program of 3 months, for nursing home residents, on ADL, balance, physical activity level, mobility and muscle strength. Methods: In this single-blind randomized clinical trial with parallel groups, nursing home residents >64 years of age from three Nordic countries were included. The intervention group (IG) was assigned to individually tailored physical and daily activities, while the control group (CG) received ordinary care. Primary outcomes were ADL and balance, and secondary outcomes physical activity level, mobility and muscle strength. Results: At baseline, 322 nursing home residents were included, of whom 266 were assessed after 3 months of intervention. Following the intervention, a significant difference was found between participants in the IG and CG on measures of balance, physical activity and transfers. The IG significantly improved walking/wheelchair speed and functional leg muscle strength. The CG had significantly deteriorated in ADL, balance and transfers. Persons who had taken part in the intervention for more than 150 min/week significantly improved their balance and physical activity level. Participation in more than 10 weeks of intervention significantly improved physical activity and walking/wheelchair speed, while a deterioration was seen in those who had participated less. Conclusion: Individually tailored intervention in nursing home residents focusing on physical and daily activities is effective in improving transfers, balance and physical activity level compared to usual care. The effect of the intervention is dependent on the total activity time.

Home-based video exercise intervention for community-dwelling frail older women: a randomized controlled trial

Background and aims: Home-based exercise is a viable solution for frail elderly individuals with difficulties in reaching exercise facilities outside home. The aim of this study was to determine the effects of a home-based video exercise program on physiological performance, functional capacity and health-related quality of life. Methods: Community-dwelling frail women ≥75 yrs, receiving public home care, were randomized into a training group (n=30) and a control group (n=31). Participants exercised for 26 minutes, three times per week for five months. Both groups received a bi-weekly telephone call. The effect of intervention was evaluated by the physical performance test, mobility-tiredness score, maximal isometric handgrip and biceps strength, lower limb explosive power, repeated chair rise (5 times), 10-m maximal walking-speed, semi-tandem balance, and health-related quality of life, as measured by EQ-5D and self-rated health. Results: Twenty-five participants (83%) in the training group and 28 (90%) in the control group completed the project. Adherence to the training protocol was on average 89.2%. At follow-up, between-group analysis revealed a significant difference only in EQ-5D (valued by time-trade-off tariffs), resulting from a significant decrease observed in the control group and a trend towards an increase in the training group (p=0.082). Significant within-group improvements, ranging from 8–35%, were also observed for the physical performance test, mobility-tiredness score, handgrip, biceps strength, chair rise, and 10-m maximal walking-speed in the training group, and for walking-speed and self-rated health in the control group. Conclusions: These results suggest that home-based training for frail older women using an exercise video induces lasting health-related quality-of-life (EQ-5D). In addition, a tendency towards improvements in physiological performance and functional capacity was observed.

Maximal oxygen uptake, muscle strength and walking speed in 85-year-old women: Effects of increased physical activity

This study explores the effect of regular training on blood pressure, maximal oxygen uptake, maximal isometric muscle strength, and walking speed in the very old. A total of 55 community-dwelling women, 85-year-old, were enrolled in a training group (N=22) or a control group (N=33). These groups were reduced to 19 and 26 subjects, respectively, after the training period. Training was performed once a week over eight months, and consisted of various exercises with particular attention to movements important for everyday activities. Training reduced diastolic blood pressure (p<0.05), and showed a similar trend for systolic blood pressure. Measurements of maximal oxygen uptake before the start of the training (15 mL min-1 kg-1) revealed a level close to the presumed limit for independent living (13 mL min-1 kg-1). Training improved VO2 max by 18% (p<0.05), whereas the control group experienced a trend towards a reduction. Maximal isometric muscle strength of both the right and left leg showed a tendency to increase with training, but no significant changes were evident in the trunk flexor and extensor muscles. The training group showed a significant increase of 17% in maximal walking speed after the training period. However, one year later, without training, this improvement was reduced to 8% (p<0.05). No major changes were observed in the control group for any of these parameters. This study demonstrates a maximal oxygen capacity in very old community-dwelling women close to a threshold level indicating dependency. Furthermore, 8 months of regular training appears to lower blood pressure, and to increase maximal oxygen uptake and maximal walking speed. This suggests that physical reactivation of the very old may reduce the risk for acquiring age-related diseases associated with an elevated blood pressure, and may improve parameters crucial for independence.

Biomechanical determinants of maximal stair climbing capacity in healthy elderly women

Stair walking is an important functional movement task that may require considerable amounts of muscle strength/power. This study aimed to perform a descriptive biomechanical analysis of maximal stair ascent in elderly women and to examine the relationship between mechanical muscle function and maximal stair ascending velocity (MAV). Seventeen healthy elderly women (age 72.4 ± 6.4) were tested for MAV, maximal multi‐joint counter movement jumping (CMJ), and maximal single‐joint isokinetic/isometric muscle moment. Peak knee joint power during MAV was the single independent parameter that explained most of the variation in MAV (50%), however, combining knee and ankle parameters in a multiple regression analysis mean joint power explained 82.4% of the variation in MAV. Generally, multi‐joint CMJ parameters showed stronger correlations with MAV than single‐joint isokinetic/isometric muscle strength parameters. MAV appeared to be highly dependent upon knee and ankle power and to a lesser extent on joint moment and range of motion. Furthermore, CMJ assessment seemed well applicable in healthy elderly individuals to distinguish between differentiated levels of maximal stair walking capacity.

A Nordic multi-center study on physical and daily activities for residents in nursing home settings: design of a randomized, controlled trial

Background and aims: Nursing home residents constitute a frail, multi-diseased and heterogeneous group. As physical activity is essential for the preservation of function, personalized training and activities are of great importance. The main objective of this study was to describe the influence of an individually tailored intervention program, in a nursing home setting, on physical capacity, degree of dependence in Activities of Daily Living (ADL), long-term participation in physical and/or daily activities, and self-rated wellbeing. The aim of the present work is to describe the overall design of the study. Methods: Nursing homes in Sweden, Norway and Denmark were involved, and 322 residents were randomized to either Intervention or Control groups. The intervention lasted for three months and consisted of physical and daily activities, led by physiotherapists and occupational therapists, and was built on their evaluations and on the goals expressed by each resident. Tests of muscle strength, mobility, balance function and confidence, ADL, level of physical activity, wellbeing and cognitive function were performed at baseline, directly after the intervention period and three months later. Results: They will be presented in articles to follow. Conclusions: Although it is a great challenge to carry out an intervention study directed toward such a frail population, it is of great interest to find out whether individually tailored and enhanced activities can lead to decreased dependence in ADL and increased wellbeing.

Exercise on Prescription. Effect of attendance on participants' psychological factors in a Danish version of Exercise on Prescription: A Study Protocol

BackgroundIn many countries exercise prescriptions are used to facilitate physical activity in a sedentary population with or in risk of developing lifestyle diseases. Some studies show a positive effect of exercise prescription on specific lifestyle diseases. Others only show moderately positive or no effect on physical activity level. Furthermore, the challenge is adherence of participants to a physically active lifestyle on a long term basis after intervention. Therefore, it is essential for offering successful prescribed interventions aiming towards behaviour change to focus on psychological and social issues as well as physiological issues. The aim of this study is to assess the short and long term development of psychological conditions in two different Exercise on Prescription groups; The Treatment Perspective and The Preventive Perspective behaviour. Thus, the aim of this paper is to describe the design used.Methods/DesignThe Treatment Perspective involves a 16 week supervised training intervention including motivational counselling. The Preventive Perspective only involves motivational counselling. The study is an evaluation of best practice and is accomplished by the use of a combination of quantitative (collected by questionnaires) and qualitative (collected by the use of semi structured interviews) measures. Comparison of The Treatment Perspective and The Preventive Perspective are performed at baseline and after 16 months. Development within the groups is measured at 4, 10, and 16 months. Self-reported measures describe physical activity, health-related quality of life, compliance with national guidelines for physical activity, physical fitness, self-efficacy, readiness to change, decisional balance, and processes of change. To elaborate self-efficacy, readiness to change, decisional balance, and processes of change, these issues were elucidated by interviews.DiscussionThis study of best practice is designed to provide information about important psychological concepts in relation to behaviour change and physical activity. The study is part of a health technology assessment of Exercise on Prescription, which apart from the psychological concepts (the patients perspective) covers the effectiveness, the organization, and the health economy.