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Strength training early after myocardial infarction.

BACKGROUND: Many activities of daily living require significant amounts of muscular strength. Time lines for current strength training guidelines preclude many myocardial infarction patients from receiving strength training as part of their cardiac rehabilitation program. This study was designed to examine the effectiveness and safety of low-to-moderate level strength training in patients early after myocardial infarction. METHODS: Fifty-seven low-risk men ( < 61 years of age, 6-16 weeks post-infarction) were randomly assigned to a control group or one of three treatment groups. All groups trained aerobically, three times per week for 12 weeks. The three treatment groups performed additional strength exercises on each training day of the last 10 weeks. These groups differed in their strength training stimulus with Group 20 performing 20 reps of 20% of 1 repetition maximum (1 RM), Group 40 performing 10 repetitions of 40% of 1 RM, and Group 60 performing 7 repetitions of 60% of 1 RM. RESULTS: Maximal strength remained unchanged in the control group (+0.5%), but increased in Groups 20, 40, and 60 by +10.5%, +11.9%, and +13.5%, respectively. The increases in strength in the treatment groups were all significantly different (P < .001) from the results of the control group, but were not significantly different from each other. For the three treatment groups, 30 of 42 subjects had one or more cardiovascular complication (arrhythmias, angina, ischemia, hypertension, hypotension) during the aerobic exercises as compared to only 1 subject with complications during the resistive exercises (P < .01). CONCLUSIONS: In selected patients, low-to-moderate intensity strength training performed early after infarction is effective and may have lower rates of cardiovascular problems than aerobic exercise.

Adult↗
PubMed2001

Neuromuscular Evaluation of Trunk-Training Exercises.

OBJECTIVE: To evaluate the neuromuscular activation profiles of trunk muscles in commonly used gymnastic strength exercises with a polymyographic set-up and to describe the training effects of each exercise. DESIGN AND SETTING: Subjects performed 9 repetitions of each of 12 gymnastic exercises. Variations of 5 trunk flexions, 5 extensions, and 2 lateral-flexion movements were performed under standardized test conditions. SUBJECTS: Ten healthy subjects (men and women) who were familiar with the exercises participated in the study. MEASUREMENTS: We recorded surface electromyograms (EMGs) from the rectus abdominis, external oblique, rectus femoris, middle trapezius, erector spinae at T12 and L3, gluteus maximus, and semitendinosus and semimembranosus muscles. Recording of each repetition cycle was triggered by a flexible electronic goniometer attached to the trunk. The raw EMG signals were rectified, smoothed, amplitude normalized to maximal voluntary contraction (MVC), and averaged for the last 8 repetitions. RESULTS: Pure spine-flexion exercises, such as a curl-up, produced sufficient and isolated activation (greater than 50% MVC) of the abdominal muscles. When flexion of the spine was combined with hip flexion (sit-up), the peak activation was increased. Lateral-flexion tasks targeted primarily the external oblique muscle, which demonstrated high activity in side-lying flexion tasks. Back- and hip-extension exercises, such as bridging and diagonal hip and shoulder extension, produced only moderate mean activities (less than 35% MVC) in the trunk-extensor muscles. Trunk-extension exercises with combined hip extension increased the EMG activity to 50% MVC but only at the end of the extension. CONCLUSIONS: Individual responses to each exercise varied markedly, which complicated the classification of exercise effects. However, within the limitations of the study, we found that the chosen abdominal exercises provided an effective training stimulus for the trunk-flexor muscles, whereas in the back- and hip-extension exercises, the neuromuscular activation tended to be too low or unspecific to qualify as muscle-specific training.

Journal Article↗
PubMed2002

The role of protein and amino acid supplements in the athlete's diet: does type or timing of ingestion matter?

Rather than the age-old debate regarding overall protein and amino acid needs of athletes, this paper focuses on the importance of timing and type of protein and amino acid ingestion relative to both muscle growth and exercise performance. Evidence discussed comes from definitive measurement techniques including net protein balance determinations (for acute studies) or quantification of muscle size or strength (for chronic studies) First, recent data indicate that consuming a small meal of mixed macronutrient composition (or perhaps even a very small quantity of a few indispensable amino acids) immediately before or following strength exercise bouts can alter significantly net protein balance, resulting in greater gains in both muscle mass and strength than observed with training alone. With aerobic exercise, some evidence suggests immediate postexercise (but perhaps not pre-exercise) supplementation is also beneficial. Second, protein type may also be important owing to variable speeds of absorption and availability, differences in amino acid and peptide profiles, unique hormonal response, or positive effects on antioxidant defense. In addition to athletes, many others who desire to regain, maintain, or enhance muscle mass or function, including those with muscle-wasting diseases, astronauts, and all of us as we age, need to ensure that nutrient availability is sufficient during the apparently critical anabolic window of time associated with exercise training sessions. Future studies are needed to fine tune these recommendations.

Amino Acids↗
PubMed2004

Body mass reduction markedly improves muscle performance and body composition in obese females aged 61-75 years: comparison between the effects exerted by energy-restricted diet plus moderate aerobic-strength training alone or associated with rGH or nandrolone undecanoate.

OBJECTIVE: To investigate the effectiveness of a body mass reduction programme entailing diet caloric restriction and moderate physical activity with or without supplementary treatment with recombinant (r) GH or steroids to improve body composition and muscle performance in severely obese women aged 61-75 years. METHODS: Twenty women were randomly assigned to one of three groups: body mass reduction alone; body mass reduction plus rGH; body mass reduction plus nandrolone undecanoate. Body composition, isotonic muscle strength and anaerobic power output during jumping were determined before and after the 3-week period. RESULTS: Whatever the experimental group considered, body mass (P<0.01), body mass index (P<0.05) and fat mass (P<0.05) decreased significantly, whereas muscle strength and power increased significantly (P<0.05) after the intervention. CONCLUSION: Small body mass reductions after 3 weeks of energy-restricted diet combined with moderate aerobic and strength exercise are associated with significant improvements in upper and lower limb muscle strength and power and reduction of fat mass in severely obese women aged 61-75 years. Although the association of rGH or nandrolone undecanoate does not appear to exert additional effects on body composition and muscle performance attained by body mass reduction alone, further additional studies with larger study groups, different dosages and more prolonged periods are required for definitive conclusions to be drawn.

Aged↗
PubMed1999

Outpatient exercise training in children with cystic fibrosis: physiological effects, perceived competence, and acceptability.

Exercise training is currently advocated as part of the treatment of patients with cystic fibrosis (CF). However, data are few that document physiologic benefits or changes in patients' perceptions of long-term training programs in children with CF. The aim of this study was to investigate the effects and acceptability of a home cycling program in children with CF. Fourteen patients (9 boys, 5 girls) with CF, mean (SD) age 14.1 (2.0) years, with mild to moderate impairment of lung function (forced expiratory volume in 1 s, mean (SD) 58.3 (16.3)% of predicted) were studied for 1 year. The first half of the study year was used to obtain baseline values at 0 and 6 months. During the second half of the year, a cycle program was carried out 5 times a week, for 20 min each day at a level of work that resulted in a heart rate of 140-160 beats/min. Once a week the cycle program was supervised by a physiotherapist. Measurements were repeated at 12 months. Effects of the exercise program were measured in terms of lung function, nutritional status, growth, muscle strength, exercise performance, perceived competence, and attitude towards the training program. Differences between the changes during the 6-month training period as compared to the 6-month control period were analyzed by multivariate statistics and nonparametric tests. Statistically significant differences (P < 0.05) between the two periods were found with respect to muscle strength of knee extensors and ankle dorsiflexors, and with respect to maximal oxygen consumption per kg body weight as well as per kg fat free mass. All changes were positive. No adverse effects were found. Perceived competence showed significant positive changes in feelings about physical appearance, general self-worth, and Total Perceived Competence Score. Scores concerning perceived acceptability of the program were significantly lower at the end of the training period; however, patients reported that they did want to continue with other sorts of training. We conclude that an exercise training program in the home can produce beneficial effects on oxygen consumption, muscle force, and perceived competence in children with CF. However, acceptability of the program was low, suggesting that long-term adherence would be poor, and hence, other sorts of training need to be identified.

Adolescent↗
PubMed2002

Exercise and muscle strength training and their effect on quality of life in patients with chronic heart failure.

BACKGROUND: There is now evidence that moderate training plays an important role in the treatment of chronic heart failure. No clear instructions exist to date as to how such training programs should be carried out. AIM: to assess the efficiency of a training program including bicycle ergometer training, moderate muscle strength training and the 6-min walk test and their influence on quality of life, anxiety and depression. METHODS AND RESULTS: Patients (67 male, 21 female) underwent a standardized 4-week training program. BASELINE DATA: LVEF=31+/-8%; LVEDD=143+/-59 ml; peak VO(2)=13.9+/-4.6 kg/ml. No adverse side effects could be observed. At discharge LVEF was 37+/-9%, (P=0.001); LVEDD=131+/-44ml (P=0.01); and peak VO(2)=15.4+/-5.0 kg/ml. Quality of life improved significantly in nearly all domains and in summary score. There were no significant changes in anxiety and depression. There is a negative correlation between the initial workload and changes in physical health (r=-0.42, P=0.001) and only a weak correlation between age and positive changes in physical health (r=0.26, P=0.05). CONCLUSIONS: A standardized training program including moderate muscle strength training could be performed safely and demonstrated improvement in clinical parameters and quality of life.

Adult↗
PubMed1995

A randomized controlled trial of a home exercise programme for elderly people with poor mobility.

Eighty-six elderly people with limited mobility and dependence in at least one activity of daily living were recruited to a home exercise study. The subjects (mean age 82 years) were allocated at random to either a strength exercise group, a mobility exercise group or a health education group. Subjects were visited for 30 minutes every 3-4 weeks by a physiotherapist who gave both verbal and written instruction. Sixty-nine of the original 86 completed the 6-month study, with five drop-outs from the strength group, ten drop-outs from the mobility group, and two drop-outs from the health education group. By the end of the study, there were no significant differences between the groups with regard to changes in outcome variables. The results showed a trend towards improvement in both the exercise groups in both Sit to Stand and Timed Get Up and Go tests, but this failed to attain statistical significance. Further work is required to identify the optimal exercise intervention for this subgroup of the elderly population.

Aged↗
PubMed1993

American College of Sports Medicine. Position Stand. Physical activity, physical fitness, and hypertension.

Hypertension is present in epidemic proportions in adults of industrialized societies and is associated with a markedly increased risk of developing numerous cardiovascular pathologies. There is a continuing debate as to the efficacy of aggressive pharmacological therapy in individuals with mild to moderate elevations in blood pressure. This has led to a search for nonpharmacological therapies, such as exercise training, for these individuals. The available evidence indicates that endurance exercise training by individuals at high risk for developing hypertension will reduce the rise in blood pressure that occurs with time. Thus, it is the position of the American College of Sports Medicine that endurance exercise training is recommended as a nonpharmacological strategy to reduce the incidence of hypertension in susceptible individuals. A large number of studies indicate that endurance exercise training will elicit a 10 mm Hg average reduction in both systolic and diastolic blood pressures in individuals with mild essential hypertension (blood pressures 140-180/90-105 mm Hg). Endurance exercise training also has the capacity to improve other risk factors for cardiovascular disease in hypertensive individuals. Endurance exercise training appears to elicit even greater reductions in blood pressure in patients with secondary hypertension due to renal dysfunction. The mode (large muscle activities), frequency (3-5 d.wk-1), duration (20-60 min), and intensity (50-85% of maximal oxygen uptake) of the exercise recommended to achieve this effect are generally the same as those prescribed for developing and maintaining cardiovascular fitness in healthy adults. Exercise training at somewhat lower intensities (40-70% VO2max) appears to lower blood pressure as much, or more, than exercise at higher intensities, which may be important in specific hypertensive populations. Physically active and fit individuals with hypertension have markedly lower rates of mortality than sedentary, unfit hypertensive individuals. Thus, it seems reasonable to recommend exercise as the initial treatment strategy for individuals with mild to moderate essential hypertension. A follow-up period should assess the efficacy of the patient's exercise program, and adjunct therapies should be implemented according to the individual patient's blood pressure and CAD risk factor goals. Individuals with more marked elevations in blood pressure (> 180/105 mm Hg) should add endurance exercise training to their treatment regimen only after initiating pharmacologic therapy. Resistive, or strength, exercise training is not recommended to lower blood pressure in individuals with hypertension when done as their only form of exercise training.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2004

The effects of a 12-week group exercise programme on physiological and psychological variables and function in overweight women.

OBJECTIVES: The aim of this study was to investigate the effect of a 12-week functional exercise programme on overweight women. METHODS: Twenty-six subjects (n=13 exercisers, n=13 controls) aged (mean+/-SD) 63 (+/-4) years completed the study. The exercise sessions were carried out twice each week for 12 weeks. The variables measured were body mass, body mass index, skin-fold thickness, resting blood pressure, total blood cholesterol, chair rise, timed 'up and go' test, 20-m walk,lifting a 1- and a 2-kg bag on to a shelf, stair walking, 'sit and reach' flexibility test, Life Satisfaction Index and Physical Self-perception Profile for Older Adults. The exercise sessions consisted of 40-min sessions during which the subjects performed aerobic and strength exercises. RESULTS: Paired analyses showed that body mass, body mass index, blood pressure (systolic and diastolic values), 'up and go' time, time to complete a 20-m walk, time to lift a 1- and a 2-kg bag with both the right and left arms onto a shelf, and stair climbing-total time and ascent time-decreased significantly in the exercise group. Also, the exercise group improved their Life Satisfaction Index score significantly compared with the control group. CONCLUSIONS: The results indicate that a functional exercise programme has the potential to improve performance in a number of physiological variables and functional activities in overweight women. The exercise programme enhanced life satisfaction.

Aged↗
PubMed1995

Improvement in wheelchair propulsion in pediatric wheelchair users through resistance training: a pilot study.

Six children, three with cerebral palsy and three with myelomeningocele, participated in a progressive, 8-week, circuit muscular strength training program. The program was designed to improve wheelchair propulsion, an important functional outcome. Subjects performed three sets of six-repetition maximum (6-RM) upper body strength exercises, three times a week. Exercises included shoulder flexion, extension, abduction, internal and external rotation, elbow flexion, extension, and shoulder flexion/elbow extension (bench press). Subjects exercised quickly with little rest between each set for approximately 30 minutes per session. All children used wheelchairs extensively and participated in a 50-m, and a 12-minute wheelchair propulsion test before and after the 8-week program. The sign test was used to determine if statistically significant (P < or = .05) wheelchair propulsion or 6-RM changes occurred over the training period. Subjects improved significantly (P < or = .031) in all muscular strength (6-RM) measures and the 12-minute distance test. There was a trend toward improvement in the 50-meter test, although this change was not significant (P < or = .05). The results indicate that progressive resistance exercise training seems to improve muscular strength and wheelchair performance in selected disabled children.

Adolescent↗
PubMed2005

[Effect of inspiratory muscle training on muscle strength and quality of life in patients with chronic airflow limitation: a randomized controlled trial].

OBJECTIVE: Chronic airflow limitation (CAL) is a significant cause of illness and death. Inspiratory muscle training has been described as a technique for managing CAL. The aim of the present study was to evaluate the effectiveness of inspiratory muscle training on improving physiological and functional variables. PATIENTS AND METHODS: Randomized controlled trial in which 35 patients with CAL were assigned to receive either an experimental (n=17) or control (n=18) intervention. The experimental intervention consisted of 2 months of inspiratory muscle training using a device that administered a resistive load of 40% of maximal static inspiratory mouth pressure (PImax). Inspiratory muscle strength, exercise tolerance, respiratory function, and quality of life were assessed. RESULTS: Significant improvement in inspiratory muscle strength was observed in the experimental training group (P=.02). All patients improved over time in both groups (P<.001). PImax increased by 8.9 cm H2O per month of training. Likewise, the health-related quality of life scores improved by 0.56 points. CONCLUSION: Use of a threshold loading device is effective for strengthening inspiratory muscles as measured by PImax after the first month of training in patients with CAL. The long-term effectiveness of such training and its impact on quality of life should be studied in a larger number of patients.

Breathing Exercises↗
PubMed1995

Effect of intensive training on the isokinetic strength and structure of lumbar muscles in patients with chronic low back pain.

STUDY DESIGN: This study investigated the effects of the intensive physical rehabilitation program on the trunk and knee extensor muscles in patients with chronic low back pain. At baseline and after 3 months, strength was measured and muscle biopsies were taken. OBJECTIVES: To evaluate the effects of strength exercises on the structure of back muscles. SUMMARY OF BACKGROUND DATA: Rehabilitation designed for chronic low back pain patients improves trunk muscle strength, mobility of the spine, and the patients' functional capacity. The effects of such programs on the structure of back muscles have not been reported previously. METHODS: Thirty patients with chronic low back pain volunteered to participate in the study. Biopsies were taken from the multifidus and vastus lateralis muscles. The sizes of Types 1 and 2 muscle fibers were measured. The peak-torques of isokinetic trunk and knee extension were determined at two different angular velocities. RESULTS: Strength increased by 19-22% (P < 0.05) in trunk extension and by 7-11% (P < 0.05) in knee extension. Type 1 fibers maintained their pre-exercise size. The size of Type 2 muscle fibers in men increased by 11% (P < 0.05) in the multifidus and by 8% (P < 0.05) in the vastus lateralis. In women, the corresponding increases were 11% (P = 0.16) and 11% (P < 0.05). The correlation between the size of Type 2 muscle fibers in the multifidus and the strength of trunk extension improved, especially in men at follow-up. CONCLUSIONS: The results of the present study suggest that training with maximal or submaximal effort may reverse the selective atrophy of Type 2 fibers in the multifidus muscles in men. Intensive training also can significantly increase the trunk extension strength in women, but women may need a longer training period than men to achieve significant structural changes in their back muscles.

Adult↗
PubMed2005

Leptin and adiponectin responses in overweight inactive elderly following resistance training and detraining are intensity related.

CONTEXT: Adiponectin and leptin are closely related to weight control and energy balance, whereas exercise affects elderly metabolic regulation and functional capacity. OBJECTIVE: The objective of this study was to investigate leptin and adiponectin responses in elderly males after exercise training and detraining. DESIGN: The study design was a 1-yr randomized controlled trial. SETTING: The study was performed at the Laboratory of Physical Education and Sport Science Department. PARTICIPANTS: Fifty inactive men [age, 65-78 yr; body mass index (BMI), 28.7-30.2 kg/m2] were recruited from a volunteer database by word of mouth and fliers sent to medical practitioners, physiotherapists, and nursing homes in the local community. INTERVENTION(S): Participants were randomly assigned to a control (n = 10), low-intensity (n = 14), moderate-intensity (n = 12), or high-intensity training (HI; n = 14) group. Resistance training (6 months, 3 d/wk, 10 exercises/three sets) was followed by 6 months of detraining. MAIN OUTCOME MEASURE(S): Strength, exercise energy cost, skinfold sum, body weight, maximal oxygen consumption, resting metabolic rate (RMR), and plasma leptin and adiponectin were determined at baseline and after training and detraining. RESULTS: Strength, maximal oxygen consumption, RMR, and exercise energy cost increased (P < 0.05) after training in an intensity-dependent manner. Skinfold sum and BMI were reduced by resistance training (P < 0.05), with HI being more effective (P < 0.05) than moderate-intensity/low-intensity training. Leptin was diminished (P < 0.05) by all treatments, whereas adiponectin increased (P < 0.05) only in HI. Detraining maintained training-induced changes only in HI. The percent leptin decrease was associated (P < 0.05) with the percent BMI decrease and the percent RMR increase, whereas the percent adiponectin increase was associated (P < 0.05) with the percent BMI decrease. CONCLUSIONS: Resistance training and detraining may alter leptin and adiponectin responses in an intensity-dependent manner. Leptin and adiponectin changes were strongly associated with RMR and anthropometric changes.

Adiponectin↗
PubMed2007

Cardiopulmonary exercise capacity, muscle strength, and physical activity in children and adolescents with achondroplasia.

OBJECTIVE: To study in children with achondroplasia the response to exercise and muscle strength compared with healthy peers and to describe the relation between exercise capacity, anthropometric factors, and physical activity. STUDY DESIGN: Patients (7 boys and 10 girls; mean age, 11.8 +/- 3.3 years) with achondroplasia performed a maximal treadmill exercise test. Anthropometric variables and muscle strength were measured and compared with the general population. The level of everyday physical activity was measured by using a diary. Functional ability was measured by using the Activity Scale for Kids. RESULTS: The exercise capacity of the children with achondroplasia was significantly reduced compared with reference values. All anthropometrical measurements differed significantly from reference values. There was a decrease in muscle strength in almost all muscle groups. We found a reduced physical activity level and impairments in functional ability. CONCLUSIONS: Cardiopulmonary exercise capacity and muscle strength in children with achondroplasia was reduced compared with reference values. Children with achondroplasia have a unique response to exercise. Clinicians should take these characteristic differences into account when the exercise capacity of subjects with achondroplasia is being tested.

Achondroplasia↗
PubMed1998

American College of Sports Medicine Position Stand. Exercise and physical activity for older adults.

ACSM Position Stand on Exercise and Physical Activity for Older Adults. Med. Sci. Sports. Exerc., Vol. 30, No. 6, pp. 992-1008, 1998. By the year 2030, the number of individuals 65 yr and over will reach 70 million in the United States alone; persons 85 yr and older will be the fastest growing segment of the population. As more individuals live longer, it is imperative to determine the extent and mechanisms by which exercise and physical activity can improve health, functional capacity, quality of life, and independence in this population. Aging is a complex process involving many variables (e.g., genetics, lifestyle factors, chronic diseases) that interact with one another, greatly influencing the manner in which we age. Participation in regular physical activity (both aerobic and strength exercises) elicits a number of favorable responses that contribute to healthy aging. Much has been learned recently regarding the adaptability of various biological systems, as well as the ways that regular exercise can influence them. Participation in a regular exercise program is an effective intervention/ modality to reduce/prevent a number of functional declines associated with aging. Further, the trainability of older individuals (including octo- and nonagenarians) is evidenced by their ability to adapt and respond to both endurance and strength training. Endurance training can help maintain and improve various aspects of cardiovascular function (as measured by maximal VO2, cardiac output, and arteriovenous O2 difference), as well as enhance submaximal performance. Importantly, reductions in risk factors associated with disease states (heart disease, diabetes, etc.) improve health status and contribute to an increase in life expectancy. Strength training helps offset the loss in muscle mass and strength typically associated with normal aging. Additional benefits from regular exercise include improved bone health and, thus, reduction in risk for osteoporosis; improved postural stability, thereby reducing the risk of falling and associated injuries and fractures; and increased flexibility and range of motion. While not as abundant, the evidence also suggests that involvement in regular exercise can also provide a number of psychological benefits related to preserved cognitive function, alleviation of depression symptoms and behavior, and an improved concept of personal control and self-efficacy. It is important to note that while participation in physical activity may not always elicit increases in the traditional markers of physiological performance and fitness (e.g., VO2max, mitochondrial oxidative capacity, body composition) in older adults, it does improve health (reduction in disease risk factors) and functional capacity. Thus, the benefits associated with regular exercise and physical activity contribute to a more healthy, independent lifestyle, greatly improving the functional capacity and quality of life in this population.

Accidental Falls↗
PubMed2004

Improvements in physical fitness in adults with Down syndrome.

The effectiveness of an exercise training program for 52 adults with Down syndrome (M age = 39.4 years) was evaluated. The training program consisted of cardiovascular (30 minutes) and strength exercise (15 minutes) for 12 weeks, 3 days a week for 45-minutes per session. Compared to control subjects, the training group improved significantly in cardiovascular fitness and muscular strength and endurance and had a slight but significant reduction in body weight. Greater effort must be made to promote increases in physical activity participation among persons with Down syndrome and developmental disabilities in order to reduce the potential health risks associated with low fitness and sedentary behavior.

Adult↗
PubMed1992

Effect of reduced frequency of training and detraining on lumbar extension strength.

To investigate the effect of reduced frequency of training and detraining on lumbar extension strength, 50 subjects (34 men, aged 34 +/- 11 yrs; and 16 women, aged 33 +/- 11 yrs) were recruited from ongoing strength training programs. Initial training consisted of 10 or 12 weeks of variable resistance lumbar extension strength exercise to volitional fatigue 1, 2, or 3 times a week. After the initial training, subjects reduced the frequency of training to once every 2 weeks (n = 18) or once every 4 weeks (n = 22) for 12 weeks. Only the frequency of training was changed; the mode, volume, and intensity of exercise remained constant for both reduced frequency of training groups. An additional ten subjects terminated training and acted as controls (detraining group). Isometric lumbar extension strength was evaluated at seven angles through a 72 degree range-of-motion before training, after training, and after reduced frequency of training or detraining. Analysis of variance with repeated measures indicated that lumbar extension strength improved (P < or = 0.05) for all groups after the initial 10 or 12 weeks of training. After 12 weeks of reduced training, the once every 2 weeks and once every 4 weeks groups showed no significant reduction in lumbar extension strength at any angle tested, whereas the detraining group demonstrated an average 55% reduction in strength. These findings indicate that isometric lumbar extension strength can be maintained for up to 12 weeks with a reduced frequency of training as low as once every 4 weeks when the intensity and the volume of exercise are maintained.

Adult↗