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The relationship of joint symptoms with exercise performance in older adults.

OBJECTIVES: The objective of this study is to determine if exercise increases joint symptoms in older adults with a history of arthritis or produces symptoms in older adults without such history. In addition, we examine whether joint symptoms explain the large observed variation in strength gain in older adults undergoing vigorous strength training exercise, and report the incidence of musculoskeletal injuries upon initiation of an exercise program. DESIGN: A population-based, single blinded, randomized controlled trial with three exercise groups and one control group. SETTING: A large urban health maintenance organization. PARTICIPANTS: Older men and women (N = 105) aged 68 to 85, with leg strength below the 50th percentile for their age, sex, height, and weight and without neuromuscular disease or active cardiovascular disease. INTERVENTIONS: Supervised exercise in 1-hour sessions, three times each week, for 24 to 26 weeks. One exercise group did strength training (ST) using weight machines (n = 25); another group did endurance training (ET) using stationary cycles (n = 25); and the third group did combined strength training and endurance training (ST+ET) (n = 25). The control group (n = 30) received no intervention. MEASUREMENTS: Strength was measured at the ankle, knee, hip, and elbow using an isokinetic dynamometer. Joint symptoms were rated on a 6-point scale (0 = none, 5 = severe). Arthritis severity was based on self-reported use of arthritis medication. Health status was measured with subscales of the SF-36 and Sickness Impact Profile (SIP). RESULTS: Joint symptoms fluctuated over time in all exercise groups, but they did not improve or worsen significantly in any group. The physical dimension of the SIP and SF-36 subscale scores, including Bodily Pain Scores, did not change over time in any group. Subjects with arthritis and joint symptoms gained as much strength with strength training as did subjects without joint symptoms. Adjustment for age, gender, baseline strength, adherence, and exercise group did not affect this finding. The rate of minor musculoskeletal injuries was 2.2 injuries per 1000 exercise hours. CONCLUSIONS: Moderate intensity stationary cycle exercise and vigorous intensity strength training do not appear to produce or exacerbate joint symptoms in older adults. Joint symptoms did not explain the large variation in gains in strength in older adults participating in a standardized strength training exercise program. Musculoskeletal injuries occurred relatively infrequently, and no major injuries occurred. In evaluating joint pain that occurs in older adults in well regulated exercise programs, clinicians should consider other etiologies before attributing pain to exercise per se.

Aged↗

Effects of exercise on bone density, balance, and self-efficacy in older women.

The effects of weighted vest walking and strength-training exercises on bone mineral density (BMD), balance, strength, and self-efficacy were tested in older women. Eighteen women, age 69.2 +/- 3.5 years, were randomly assigned to an exercise group (EG) (n = 9), or a sedentary control group (CG) (n = 9). The EG participated in 32 weeks (three 1-h sessions/week) of supervised strength training and walking, stair climbing, and balance exercises while wearing weighted vests. The CG did not exercise. All women took Ca2+ and vitamin D during the study period. Measures included 1) BMD of the hip and lumbar spine measured by dual-energy X-ray absorptiometry, 2) strength, 3) balance, and 4) scores on a self-efficacy instrument. The EG had significant improvements in bone density of the femoral neck and balance and a significant weight loss (P < 0.05). There were no changes in self-efficacy in either group.

Aged↗

Strength gains following different combined concentric and eccentric exercise regimens.

BACKGROUND: Loss of muscle strength and cross-sectional area is a well-recognized consequence of spaceflight. Existing countermeasures have not been fully effective in preventing muscle weakness and atrophy in microgravity. Resistance exercise programs that consist of both eccentric and concentric actions have resulted in strength and muscle mass gains in ground-based studies. HYPOTHESES: 1) A concentric/eccentric combination exercise regimen (with a bias of either concentric or eccentric exercise) will result in a greater strength gain than concentric exercise alone; and 2) an eccentrically biased regimen will result in the greatest strength gain of all. METHODS: The 31 subjects were randomly assigned to one of three isokinetic exercise groups (CON-ECC: 75% concentric and 25% eccentric; ECC-CON: 75% eccentric and 25% concentric; CON: 100% concentric); each subject trained the right leg 3 d per week for 5 wk. Pre- and post-training isokinetic concentric/ eccentric strength tests and DEXA scans assessed changes in muscle strength and/or mass. RESULTS: All three groups showed an increase in eccentric muscle strength with the CON group showing the smallest gain (10.1%). Significantly larger gains were noted in the two combination groups (19.5%, 18.1%; p < 0.042), with the largest gains in eccentric strength. No significant change was noted in muscle mass. CONCLUSIONS: A resistance exercise protocol which includes eccentric as well as concentric exercise, particularly when the eccentric exercise is emphasized, appears to result in greater strength gains than concentric exercise alone. Findings suggest eccentric exercise may be an important component of the in-flight resistance exercise protocol for long-duration spaceflight.

Adult↗

Exercise in pregnancy and the postpartum period.

OBJECTIVE: To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neonatal implications of aerobic and strength-conditioning exercises in pregnancy. OUTCOMES: Knowledge of the impact of exercise on maternal, fetal, and neonatal morbidity, and of the maternal measures of fitness. EVIDENCE: MEDLINE search from 1966 to 2002 for English-language articles related to studies of maternal aerobic and strength conditioning in a previously sedentary population, maternal aerobic and strength conditioning in a previously active population, impact of aerobic and strength conditioning on early and late pregnancy outcomes, and impact of aerobic and strength conditioning on neonatal outcomes, as well as for review articles and meta-analyses related to exercise in pregnancy. VALUES: The evidence collected was reviewed by the Society of Obstetricians and Gynaecologists of Canada (SOGC Clinical Practice Obstetrics Committee) with representation from the Canadian Society for Exercise Physiology, and quantified using the evaluation of evidence guidelines developed by the Canadian Task Force on the Periodic Health Exam. RECOMMENDATIONS: 1. All women without contraindications should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during their pregnancy. (II-1,2B) 2. Reasonable goals of aerobic conditioning in pregnancy should be to maintain a good fitness level throughout pregnancy without trying to reach peak fitness or train for an athletic competition. (II-1,2C) 3. Women should choose activities that will minimize the risk of loss of balance and fetal trauma. (III-C) 4. Women should be advised that adverse pregnancy or neonatal outcomes are not increased for exercising women. (II-1,2B) 5. Initiation of pelvic floor exercises in the immediate postpartum period may reduce the risk of future urinary incontinence. (II-1C) 6. Women should be advised that moderate exercise during lactation does not affect the quantity or composition of breast milk or impact infant growth. (I-A) VALIDATION: This guideline has been approved by the SOGC Clinical Practice Obstetrics Committee, the Executive and Council of SOGC, and the Board of Directors of the Canadian Society for Exercise Physiology. SPONSORS: This guideline has been jointly sponsored by the Society of Obstetricians and Gynaecologists of Canada and the Canadian Society for Exercise Physiology.

Adult↗

Acute effect of alternating heavy and light resistances on power output during upper-body complex power training.

This study investigated the effect on upper-body power output of manipulating resistances during contrast or complex power training. This power-training strategy typically entails the athlete alternating sets of a heavy resistance in a strength-oriented exercise with sets of lighter resistances in a power-oriented exercise. Sixteen rugby league players, who were experienced in power training and who performed complex training on a regular basis, served as subjects for this study and were divided equally into a control (Con) or experimental (Exp) group. Both groups were pre- and posttested for power output while performing explosive bench press throws in a Smith machine with a resistance of 50 kg (BT P50). The Exp group performed an intervention strategy of a 6-repetition set of bench presses with a resistance of 65% of 1 repetition maximum (65% 1RM) between tests. At the pretest occasion, no differences were observed between the groups in power output; however, at the posttesting, a significant difference in power output was observed between the groups in the BT P50. The 4.5% increase in the power output recorded during the posttesting BT P50 for the Exp group was determined to be significantly different from all other scores (p < or = 0.05). These data indicate that the performance of a set of heavy resistance strength training exercise between power training sets will acutely enhance power output in the second power training set. This effect has been previously theorized as possibly due to some combination of acute neural or mechanical adaptations.

Analysis of Variance↗

Randomised controlled trial of a general practice programme of home based exercise to prevent falls in elderly women.

OBJECTIVE: To assess the effectiveness of a home exercise programme of strength and balance retraining exercises in reducing falls and injuries in elderly women. DESIGN: Randomised controlled trial of an individually tailored programme of physical therapy in the home (exercise group, n = 116) compared with the usual care and an equal number of social visits (control group, n = 117). SETTING: 17 general practices in Dunedin, New Zealand. SUBJECTS: Women aged 80 years and older living in the community and registered with a general practice in Dunedin. MAIN OUTCOME MEASURES: Number of falls and injuries related to falls and time between falls during one year of follow up; changes in muscle strength and balance measures after six months. RESULTS: After one year there were 152 falls in the control group and 88 falls in the exercise group. The mean (SD) rate of falls was lower in the exercise than the control group (0.87 (1.29) v 1.34 (1.93) falls per year respectively; difference 0.47; 95% confidence interval 0.04 to 0.90). The relative hazard for the first four falls in the exercise group compared with the control group was 0.68 (0.52 to 0.90). The relative hazard for a first fall with injury in the exercise group compared with the control group was 0.61 (0.39 to 0.97). After six months, balance had improved in the exercise group (difference between groups in change in balance score 0.43 (0.21 to 0.65). CONCLUSIONS: An individual programme of strength and balance retraining exercises improved physical function and was effective in reducing falls and injuries in women 80 years and older.

Accidental Falls↗

Personal exercise habits and counseling practices of primary care physicians: a national survey.

OBJECTIVE: Regular physical activity can reduce the incidence and prevalence of many chronic diseases. A vast majority of Americans cite their physician as their primary source of information regarding healthy lifestyle decisions. This study was designed to obtain information about the personal exercise behavior and counseling practices of primary care physicians, to evaluate the relationship between their personal and professional exercise practices, and to determine whether physician specialty is associated with these practices. DESIGN: A cross-sectional survey was mailed to a randomly selected sample of primary care physicians in the United States. A questionnaire was used to obtain detailed information on the personal exercise habits, counseling practices, and barriers to counseling of these physicians, regarding both aerobic exercise and strength training. PARTICIPANTS: 298 primary care physicians, comprising 84 family practitioners, 79 pediatricians, 58 geriatricians, and 77 internists. MAIN OUTCOME MEASURES: Frequency of physician exercise, exercise counseling, and relationship between these practices. RESULTS: Physicians who perform aerobic exercise regularly are more likely to counsel their patients on the benefits of these exercises, as are physicians who perform strength training. Pediatricians and geriatricians counsel fewer patients about aerobic exercise than family practitioners and internists. Counseling regarding strength training is less common in all physician groups surveyed, and lowest among pediatricians, of whom 50% did not advise these exercises for any of their patients. Inadequate time was noted by 61% and inadequate knowledge and/or experience by 16% of respondents as the major barriers to counseling regarding aerobic exercise. CONCLUSION: Physicians who exercise are more likely to counsel their patients to exercise. Inadequate time and knowledge/experience regarding exercise are the most common barriers to counseling identified. These findings suggest strategies that might increase physician exercise counseling behavior.

Attitude to Health↗

Electrical stimulation in exercise of the quadriceps femoris muscle.

Thirty-seven healthy subjects took part in an investigation to determine if the application of electrical stimulation to normal muscle, in combination with exercise, augments strength. Subjects were divided into three groups. Grwoup A (n = 14) was a control group (no exercise, no electrical stimulation). Group B members (n = 11) engaged in 10 sessions of maximum isometric exercise, and Group C subjects (n = 12) performed 10 sessions of maximum isometric exercise while simultaneously receiving electrical stimulation. The knee extensor muscles of subjects in Groups B and C increased in strength. However, the strength gains for Groups B and C were equivalent, suggesting that electrical stimulation combined with maximum isometric contractions has no greater effect on enhancing strength than does conventional static exercise.

Adult↗

Influences of strength, stretching and circulatory exercises on flexibility parameters of the human hamstrings.

The purpose of this study was to compare the effect of resistance training, static and ballistic stretching and stationary cycling on the range of motion (ROM) and end ROM torque of hip joint flexion, resting tension of the hamstrings and stretch-induced electromyographic (EMG) activity of the hamstrings. Four separate experimental groups performed either 15 min resistance training of the hamstrings (n = 12), 15 min static stretching of the hamstrings (n = 14), 15 min ballistic stretching of the hamstrings (n = 16), or 15 min stationary cycling (n = 12). A control group (n = 15) remained resting for 15 min. ROM was increased after static and ballistic stretching and after stationary cycling. ROM remained unchanged in the resistance training group as well as in the control group. End ROM torque showed a significant increase after static and ballistic stretching. Static and ballistic stretching and stationary cycling decreased EMG activity significantly. Resting tension was decreased only after stationary cycling (p < 0.1). The constancy of the muscle resting tension suggests that merely the subjects' tolerance to higher stretching strain brings about the enlargement of ROM after short-term stretching exercises. The enlargement of ROM after stationary cycling could have been caused by the poor decrease of resting tension.

Adult↗

A home-based, transtheoretical change model designed strength training intervention to increase exercise to prevent osteoporosis in Iranian women aged 40-65 years: a randomized controlled trial.

Physical activity (PA) helps to prevent osteoporosis, but older women are often sedentary. This study used a pre-post randomized controlled design to evaluate a 12-week exercise education intervention program based on the stages of change (SoC) and processes of change from the transtheoretical change model (TTM) to improve adherence with strength and balance training recommendations at levels sufficient to prevent osteoporosis in Iranian women aged 40-65 years. The home-based exercise prescription consisted of strength and balance training that was progressive, individually tailored and included a walking program. Individuals in the training group (n=61) had a positive, significant progression in psychological SoC (P<0.001), whereas no progression in stages occurred in the control group (n=55). After the intervention, the training group demonstrated significant improvements in PA, lower body muscle strength, static and dynamic balance, with no significant changes in the control group. These results support the applicability of the TTM for a PA intervention and indicate that this training program is very effective in improving balance and lower body strength in older women.

Aged↗

The effect of an exercise intervention on aerobic fitness, strength and quality of life in children with haemophilia (ACTRN012605000224628).

BACKGROUND: Children with haemophilia have lower levels of fitness and strength than their healthy peers. We present the protocol of a study designed to determine whether an exercise intervention improves quality of life, aerobic fitness and strength in children with haemophilia. METHODS/DESIGN: The study will be a randomised, assessor-blinded, controlled trial of exercise treatment. Seventy children aged between 6 and 18 years with haemophilia or von Willebrand disease will be recruited from two paediatric haemophilia clinics in NSW. Each participant will be allocated to an exercise group or a control group using a concealed allocation procedure. The control group will receive usual medical care while the intervention group will receive usual medical care plus an exercise program for 12 weeks. Outcomes (VO2peak, knee extensor strength and quality of life) will be measured at baseline and on completion of the exercise program by a blinded assessor. The primary analysis will be conducted on an intention to treat basis. The effects of the exercise intervention on each of the three primary outcomes will be estimated from between-group differences in the mean outcome adjusted for baseline scores. DISCUSSION: This study will be the first randomised controlled trial to examine the effects of a structured exercise program on fitness and quality of life in children with haemophilia.

Journal Article↗

Prospective ten-month exercise intervention in premenarcheal girls: positive effects on bone and lean mass.

Enhancement of bone mineral acquisition during growth may be a useful preventive strategy against osteoporosis. The aim of this study was to explore the lean mass, strength, and bone mineral response to a 10-month, high-impact, strength-building exercise program in 71 premenarcheal girls, aged 9-10 years. Lean body mass, total body (TB), lumbar spine (LS), proximal femur (PF), and femoral neck (FN) bone mineral were measured using the Hologic QDR 2000+ bone densitometer. Strength was assessed using a grip dynamometer and the Cybex isokinetic dynamometer (Cybex II). At baseline, no significant difference in body composition, pubertal development, calcium intake, physical activity, strength, or bone mineral existed between groups. At completion, there were again no difference in height, total body mass, pubertal development, calcium intake, or external physical activity. In contrast, the exercise group gained significantly more lean mass, less body fat content, greater shoulder, knee and grip strength, and greater TB, LS, PF, and FN BMD (exercise: TB 3.5%, LS 4.8%, PF 4.5%, and FN 12.0%) compared with the controls (controls: TB 1.2%, LS 1.2%, PF 1.3%, and FN 1.7%). TB bone mineral content (BMC), LS BMC, PF BMC, FN BMC, LS bone mineral apparent density (BMAD), and FN bone area also increased at a significantly greater rate in the exercise group compared with the controls. In multiple regression analysis, change in lean mass was the primary determinant of TB, FN, PF, and LS BMD accrual. Although a large proportion of bone mineral accrual in the premenarcheal skeleton was related to growth, an osteogenic effect was associated with exercise. These results suggest that high-impact, strength building exercise is beneficial for premenarcheal strength, lean mass gains, and bone mineral acquisition.

Body Height↗

Mechanisms contributing to knee extensor strength loss after prolonged running exercise.

The aim of this study was to identify the mechanisms that contribute to the decline in knee extensor (KE) muscles strength after a prolonged running exercise. During the 2 days preceding a 30-km running race [duration 188.7 +/- 27.0 (SD) min] and immediately after the race, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 12 trained runners. Superimposed twitches were also delivered during isometric maximal voluntary contraction (MVC) to determine the level of voluntary activation (%VA). The vastus lateralis electromyogram was recorded. KE MVC decreased from pre- to postexercise (from 188.1 +/- 25.2 to 142.7 +/- 29.7 N x m; P < 0.001) as did %VA (from 98.8 +/- 1.8 to 91.3 +/- 10.7%; P < 0.05). The changes from pre- to postexercise in these two variables were highly correlated (R = 0.88; P < 0.001). The modifications in the mechanical response after the 80-Hz stimulation and M-wave peak-to-peak amplitude were also significant (P < 0.001 and P < 0.05, respectively). It can be concluded that 1) central fatigue, neuromuscular propagation, and muscular factors are involved in the 23.5 +/- 14.9% reduction in MVC after a prolonged running bout at racing pace and 2) runners with the greatest KE strength loss experience large activation deficit.

Adult↗