Resistance training combined with bench-step aerobics enhances women's health profile

Moderators of Resistance Training Effects in Healthy Young Women: A Systematic Review and Meta-analysis

ABSTRACT

Molinari, T, Radaelli, R, Rech, A, Brusco, CM, Markarian, AM, and Lopez, P. Moderators of resistance training effects in healthy young women: A systematic review and meta-analysis. J Strength Cond Res 38(4): 804-814, 2024-To systematically review and analyze the effects of resistance-based exercise programs and potential moderators of change in body fat percentage, whole-body fat and lean mass, muscle hypertrophy, muscle strength, and muscle power/rapid force in healthy young women (between 18 and 35 years). A systematic search was undertaken in 7 databases from inception to May 2022. Eligible randomized controlled trials examined the effects of resistance-based exercise programs on outcomes of interest in healthy young women. Meta-analysis was undertaken with a 3-level mixed-effects model. Associations between standardized mean difference (SMD) and potential moderators (number of sessions, weekly volume, and intensity) were tested by meta-regression models. Statistical significance was set at an α level of 0.05, whereas an α level of 0.05-0.10 was also considered for potential moderators of resistance training effects. Forty articles ( n = 1,312) were included. Resistance-based exercise programs resulted in a significant improvement of 0.4 SMD (95% confidence intervals [95% CI]: 0.2 to 0.5, p < 0.001) in lean mass/muscle hypertrophy and 1.2 SMD (95% CI: 0.9 to 1.5, p < 0.001) in muscle strength. A higher number of sessions was associated with changes in lean mass/muscle hypertrophy ( β = 0.01 ± 0.00, p = 0.009), whereas a higher weekly volume approached statistical significance to moderate changes in muscle strength ( β = 0.01 ± 0.01, p = 0.053). Body fat percentage (-0.4 SMD, 95% CI: -0.6 to -0.1, p = 0.006) and muscle power/rapid force (0.6 SMD, 95% CI: 0.2 to 1.1, p = 0.011) were significantly improved. In conclusion, a higher resistance training volume was associated with greater improvements in lean mass/muscle hypertrophy, muscle strength, and body fat percentage, whereas muscle power/rapid force improvements were observed irrespective of prescription characteristics. These findings may help in designing resistance training programs for muscle hypertrophy, strength and power, and body fat percentage in healthy women.

Effects of Physical Activity Interventions on Strength, Balance and Falls in Middle-Aged Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Weak lower body strength and balance impairments are fundamental risk factors for mobility impairments and falls that can be improved by physical activity (PA). Previous meta-analyses have focused on these risk factors in adults aged ≥ 65 years. Yet, the potential of PA for improving these risk factors in middle-aged populations has not been systematically investigated. This systematic review and meta-analysis aim to examine the effect of general and structured PA on lower limb strength, postural balance and falls in middle-aged adults.

METHODS

A computerized systematic literature search was conducted in the electronic databases MEDLINE, CINAHL, Web of Science and Cochrane Library. PA intervention types were classified according to the ProFaNE taxonomy. Randomized controlled trials exploring the effects of PA on strength (e.g., leg press one-repetition-maximum), balance (e.g., single limb stance) and falls (e.g., fall rates) in adults aged 40-60 years were systematically searched and included in a network analysis. Moderator analyses were performed for specific subgroups (age, sex, low PA). The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database (PEDro) Scale.

RESULTS

Out of 7170 articles screened, 66 studies (median PEDro score 5) with 3387 participants were included. Strong, significant effects on muscle strength were found for strength (SMD = 1.02), strength-aerobic (SMD = 1.41), strength-endurance (SMD = 0.92) and water-based (SMD = 1.08) training (52 studies, I² = 79.3%). Strength training (SMD = 1.16), strength-aerobic (SMD = 0.98) and 3D training (SMD = 1.31) improved postural balance (30 studies, I² = 88.1%). Moderator analyses revealed significant effects of specific intervention types on certain subgroups and subdomains of strength and balance. No studies were found measuring falls.

CONCLUSIONS

Structured PA interventions in middle-aged adults improve strength and balance outcomes related to functional impairments and falls. Strength training increases both strength and balance and can be recommended to prevent age-related functional decline. However, the interpretability of the results is limited due to considerable heterogeneity and the overall low methodological quality of the included studies. Long-term trials are needed to determine the preventive potential of PA on strength, balance and falls. This meta-analysis may inform guidelines for tailored training during middle age to promote healthy aging. Prospero registration: CRD42020218643.

A Chair-Based Music-Kinetic Combined Exercise Program as an Alternative Approach for Increasing Health, Functional Capacity, and Physical Fitness Indices in Middle-Aged Pre-Menopausal Women

Lately, chairs have been widely used as a cheap, easily accessible, safe, and effective training means in different settings (e.g., in gyms, the house, workplaces, and in rehabilitation). This study investigated the effectiveness of a 10-week chair-based music-kinetic integrated combined exercise program on health, functional capacity, and physical fitness indicators of middle-aged pre-menopausal women. A total of 40 healthy women (40-53 years) were assigned to two groups: exercise (EG) and control (CG). The EG followed a 10-week (3 times/weekly; 30 training sessions) chair-based exercise program including aerobic dance, flexibility, coordination, and strength exercises with body weight or auxiliary means. Selected indicators of health, functional capacity, and physical fitness were evaluated before and after the 10 weeks. Following the program, the EG significantly reduced their body fat (-2.5%), blood pressure (by -4.5 to -5.5%), the time during the timed up-and-go (TUG) test (by -10.27%), heart rate (by -6.35 to -13.78%), and the rate of perceived exertion (by -24.45 to -25.88%), while increasing respiratory function (3.5-4%), flexibility (12.17%), balance (50.38-51.07%), maximal handgrip strength (10-12.17%), and endurance strength (43.87-55.91%). The chair-based combined music-kinetic exercise program was effective and could be safely used in different settings to improve health, functional capacity, and physical fitness in middle-aged women.

An exercise prescription for patients with lung cancer improves the quality of life, depression, and anxiety

Introduction

Lung cancer has the highest rates of morbidity and mortality among all cancers. Patients with lung cancer inevitably confront psychosocial discomforts and progressively experience depression and anxiety that potentially impact the clinical outcomes [e.g., quality of life (QoL)]. These mental disorders in patients with lung cancer may effectively be alleviated with prescribed Chinese traditional mind-body exercises. This study aimed to determine the effect of the exercise prescription containing Chinese traditional mind-body exercise on QoL, depression, and anxiety in patients with lung cancer.

Methods

In this study, 52 patients with non-small cell lung cancer (NSCLC) recruited from the China-Japan Friendship Hospital were divided into two groups, namely, the experimental group (N = 26) and the control group (N = 26). The experimental group was treated with an 8-week exercise prescription containing aerobic and resistance training. The control group received the usual care during the study period. The QoL, depression, and anxiety were separately investigated using EORTC QLQ-C30, EORTC QLQ-LC13, the Self-Rating Depression Scale (SDS), and the Self-Rating Anxiety Scale (SAS) at baseline and post-intervention. The scores of questionnaires were analyzed using the paired sample and independent sample t-tests to explore the intragroup and intergroup differences, respectively.

Results

The EORTC QLQ-C30 scores for physical functioning, role functioning, emotional functioning, and global QoL in the experimental group at post-intervention were significantly higher than those at baseline. The EORTC QLQ-C30 scores for fatigue, pain, dyspnea, and insomnia in the experimental group at post-intervention were significantly lower than those at the baseline. The SDS scores (baseline: 57.74 ± 8.77 vs. post-intervention: 51.42 ± 7.31, p < 0.05) and the SAS scores (baseline: 56.63 ± 9.39 vs. post-intervention: 49.16 ± 7.83, p < 0.05) in the experimental group at post-intervention were significantly lower than those at baseline.

Conclusions

The 8-week exercise prescription containing moderate-intensity Baduanjin (5 days per week) can effectively alleviate QoL, depression, and anxiety in patients with NSCLC. Our exercise prescription is an effective supportive treatment for lung cancer patients with depression and anxiety.

Clinical trial registration

Chinese Clinical Trial Registry (ChiCTR1900025121).

Twelve-Weeks of Bench-Step Exercise Training Ameliorates Cardiopulmonary Fitness and Mood State in Patients with Schizophrenia: A Pilot Study

Background and objectives: Unhealthy, physically inactive lifestyles increase the risk of future cardiovascular events and impaired physical fitness in individuals with schizophrenia. Insufficient literature exists to provide fundamental information about appropriate exercise training modality for this population. This pilot study preliminarily investigated the effects of a 12-week moderate-intensity bench-step exercise training (BSET) program on cardiopulmonary fitness, mood state, and cognition in patients with schizophrenia. Methods: Twenty-eight patients with schizophrenia completed this study. The participants were allocated into either bench-step exercise-training (BSET; N = 14) or control (CTRL; N = 14) groups according to their preferences. The BSET group received a 12-week bench-step intervention, whereas the CTRL group did not participate in any training. The Beck Depression Inventory-II (BDI-II), 6-min walk test (6MWD), and Symbol Digit Modalities Test (SDMT) were assessed at baseline (PRE) and at the end of the intervention (POST) to determine mood state, endurance fitness, and attention, respectively. Results: After a 12-week BSET intervention, the 6MWD was significantly increased in the BSET (p = 0.007) but not in the CTRL (p > 0.05). The participants with BSET intervention showed a significant decrease in BDI-II at the end of the intervention (p = 0.03). However, SDMT scores were not different in both BSET and CTRL (p > 0.05). Conclusions: This study demonstrated that the 12-week intervention of moderate-intensity bench-step exercise training (frequency: 1 session/week; each session of 30 min; step cadence: 96 beats/min) might effectively enhance cardiopulmonary fitness and mood state in patients with schizophrenia. However, attention did not change after the bench-step exercise intervention.

Physiological Exercise and Post-Exercise Effects of Inverse Sequences of Combined Bench-Step Aerobics and Resistance Exercise

The purpose of this study was to compare the effects of using inverse sequences of combined bench-step aerobics and resistance exercise on cardiorespiratory, hemodynamic and perceptual variables during exercise and one-hour post-exercise. The tested sequences were bench-step aerobics immediately before and immediately after resistance exercise. Thirteen apparently healthy and physically active women (age = 21.9 ± 6.1 years, body height = 160 ± 0.1 cm, body mass = 58.8 ± 7.5 kg, estimated fat mass = 17.2 ± 2.0% and estimated maximal oxygen uptake = 37.5 ± 2.6 mL∙kg-1∙min-1) performed a 20-minute bench-step aerobics routine, immediately before (STEP_RES) and after (RES_STEP) resistance exercise. Oxygen uptake and heart rate were continuously measured, systolic and diastolic blood pressure, body temperature and perceived exertion were measured at rest, immediately after each type of exercise and at 15, 30, 45 and 60 min after exercise. When resistance exercise was performed first (RES_STEP), oxygen uptake was higher (23.2 ± 3.9 vs. 20.5 ± 4.8 mL∙kg-1∙min-1), but the heart rate (164.5 ± 9.1 vs. 173.9 ± 11.7 bpm) and body temperature (36.5 ± 0.4 vs. 37.6 ± 0.6 ºC) were lower. In both sequences, the type of exercise performed first was pointed out with a lower perceived exertion or lower perceived intensity. Exercise and 60-min post-exercise blood pressure had a similar response in both sequences, and systolic blood pressure along with diastolic blood pressure were lower than pre-exercise from 30 min until 60 min post-exercise. The results suggest that the sequence affected oxygen uptake and perceived exertion during exercise and that this total workload, despite the sequence, promoted a post-exercise blood pressure decrease in normotensive participants.

Effects of 8-week of fitness classes on blood pressure, body composition, and physical fitness

BACKGROUND

Fitness activities such as indoor cycling (IC), Zumba® (ZU) and body pump (BP) are practiced by large segments of population. There are no studies showing which kind of fitness activity can produce more health benefits. The purpose of this study was to compare the effects of 8-week of IC, alone or combined with ZU (IC+ZU), or BP (IC+BP), on blood pressure, body composition, and physical fitness.

METHODS

Forty-eight participants were randomly assigned to four groups: IC, IC+ZU, IC+BP or control group (CG). Before and after 8-week of training, systolic (SBP) and diastolic blood pressure (DBP), fat, lean and bone mass, body circumferences, resting heart rate, aerobic fitness, limbs strength and vertical jump height (VJH) were assessed.

RESULTS

The IC and IC+ZU experienced significant decreases in SBP and DBP, which were significantly greater, compared to CG. Between-group comparisons showed greater decreases in body mass (BM) and body fat mass percentage (BFM) in IC compared to all groups, also significant differences were observed between IC+ZU and IC+B with CG. Decreases in neck, pectoral, waist and hip circumferences were found in IC, IC+ZU and IC+BP compared to CG. All experimental groups significantly increased 10RM leg press and leg flexion, VJH and VO2max compared to CG.

CONCLUSIONS

Fitness classes of IC, alone or combined with ZU or BP, are effective in reducing blood pressure and improving body composition and physical fitness. The IC is the most effective in reducing BM and BFM.

CARDIOVASCULAR AND STRENGTH ADAPTATIONS IN CONCURRENT TRAINING IN HYPERTENSIVE WOMEN

ABSTRACT Introduction Physical exercise has been recommended as a non-pharmacological strategy for preventing and controlling hypertension. Objective To verify chronic cardiovascular and muscle strength adaptations in hypertensive women who underwent 12 weeks of concurrent training (CT) in different orders. Methods Twenty hypertensive women were randomly assigned into 2 groups: resistance exercise-endurance group (REE; 56.00 ± 5.20 years; 78.95 ± 8.28 kg; 155.10 ± 5.30 cm; 33.00 ± 5.30 kg.m-2) and endurance-resistance exercise group (ERE; 57.10 ± 13.38 years; 76.56 ± 18.87 kg; 155.50 ± 8.18 cm; 31.41 ± 5.84 kg.m-2). The endurance exercise was composed of 3 sets of 4 exercises, with 8-RM loads with a 90-second break between sets and exercises. The resistance exercise lasted for 25 minutes and was of progressive intensity. Muscle strength (8-RM), systolic and diastolic blood pressure, heart rate, and double product were assessed pre- and post-exercise. Results The ANOVA showed significant increases in strength for all exercises (p <0.0001) regardless of the order of the concurrent training (bench press, p = 0.680; leg press, p = 0.244; seated row, p = 0.668; and leg extension, p = 0.257). No significant differences in systolic (p = 0.074) and diastolic blood pressures (p = 0.064) were observed for different CT conditions. However, significant reductions in systolic (p = 0.0001) and diastolic blood pressures (p = 0.006) and double product (p = 0.006) only occurred in the REE group. Conclusion Endurance training and resistance exercise promote significant muscle strength gains after 12 weeks of training regardless of CT order in hypertensive women. Beneficial cardiovascular responses (SBP, DBP, and RPP) were also observed when endurance training was initiated. Level of evidence I; Therapeutic Studies - Investigating Treatment Outcomes.

Bench stepping with incremental heights improves muscle volume, strength and functional performance in older women

AIM

Task-specific exercises such as bench stepping can improve functional ability and reduce falling incidents in older adults. However, such exercises are often not optimized to improve muscle volume and force-velocity characteristics. This study determined the effects of a 12-week stepping program using incremental step heights (STEEP), on muscle volume, strength, power, functional ability and balance performance in older women.

METHODS

Forty-five community-dwelling women (69y ± 4) were randomly assigned to the STEEP group or a non-training CONTROL group. Training intensity was primarily determined by step height, while training volume remained equal. Thigh muscle volume (CT-scan), force-velocity characteristics of the knee extensors (Biodex dynamometer) and functional ability (Short Physical Performance Battery, timed stair ascent, 10-m walk test and countermovement jump height) were determined pre- and post-intervention. In addition, 3D trunk accelerations were recorded at the lower back to assess balance during the Short Physical Performance Battery balance tests.

RESULTS

Two-way ANOVA showed that the STEEP program increased thigh muscle volume, knee extensor isometric peak torque, dynamic peak power, unloaded rate of velocity development and improved performance on all functional tests to a greater extent than CONTROL (p < .05), except the countermovement jump. No improvements were found for peak velocity and balance performance (p > .05).

CONCLUSION

Our results indicate that bench step training with incremental step heights simultaneously improves functional ability, thigh muscle volume and force-velocity characteristics of the knee extensors in older women.

Weight bearing exercise can elicit similar peak muscle activation as medium-high intensity resistance exercise in elderly women

PURPOSE

To assess whether stepping-based weight bearing exercise (WBE) can elicit peak activation of upper leg muscles similar to resistance exercise (RE) at an intensity required to induce strength gains in elderly women.

METHODS

Muscular activation of several upper leg muscles was measured during RE and WBE in a cohort of 19 healthy elderly women (69.3 ± 3.4 years). WBE consisted of forward and lateral stepping with step heights of 10, 20 and 30 cm. Muscular activation was compared to 60% of one-repetition maximum (1-RM) of congruent RE.

RESULTS

Peak activation during WBE was higher than RE at 60% 1-RM during forward and lateral stepping in vastus lateralis starting at 20 cm (p = 0.049 and p = 0.001), and biceps femoris at 30 cm step height (p = 0.024 and p = 0.030). Gluteus maximus peak activation matched RE at 60% 1-RM at 20 and 30 cm step height regardless of step direction (p ≥ 0.077). Peak activation of the rectus femoris and gluteus medius matched RE activation at 60% 1-RM during lateral stepping at 30 cm (p = 0.355 and p = 0.243, respectively) but not during forward stepping. WBE did not induce similar activation as RE in the semitendinosus.

CONCLUSION

In WBE, most upper leg muscles were recruited at an equal or higher intensity than in RE at 60% 1-RM. Lateral stepping at 30 cm step height showed the highest training potential of all WBE's applied.

Causes of motor system overload in step aerobics: Literature review

Many publications have indicated the positive impact of step aerobics on health. Although step aerobics aims to improve endur­ance and other health parameters, injuries incurred from overload happen to both instructors and participants. Values of vertical ground reaction force (vGRF) while stepping on and off the bench do not lead to overload on the motor system - they are simi­lar to the values obtained for walking or stair climbing. One reason for injuries may be the step workout technique. Overloads may be caused by incorrect technique of foot positioning on the bench, small knee angle during stepping off, and small angle of trunk flexion. This study presents an overview of current research on the load of the motor system in step aerobics.

Elastic Resistance Effectiveness on Increasing Strength of Shoulders and Hips

Picha, KJ, Almaddah, MR, Barker, J, Ciochetty, T, Black, WS, and Uhl, TL. Elastic resistance effectiveness on increasing strength of shoulders and hips. J Strength Cond Res 33(4): 931-943, 2019-Elastic resistance is a common training method used to gain strength. Currently, progression with elastic resistance is based on the perceived exertion of the exercise or completion of targeted repetitions; exact resistance is typically unknown. The objective of this study was to determine whether knowledge of load during elastic resistance exercise will increase strength gains during exercises. Participants were randomized into 2 strength training groups, elastic resistance only and elastic resistance using a load cell (LC) that displays force during exercise. The LC group used a Smart Handle (Patterson Medical Supply, Chicago, IL, USA) to complete all exercises. Each participant completed the same exercises 3 times weekly for 8 weeks. The LC group was provided with a set load for exercises, whereas the elastic resistance only group was not. The participant's strength was tested at baseline and program completion, measuring isometric strength for shoulder abduction (SAb), shoulder external rotation (SER), hip abduction (HAb), and hip extension (HEx). Independent t-tests were used to compare the normalized torques between groups. No significant differences were found between groups. Shoulder strength gains did not differ between groups (SAb p > 0.05; SER p > 0.05). Hip strength gains did not differ between groups (HAb p > 0.05; HEx p > 0.05). Both groups increased strength because of individual supervision, constantly evaluating degree of difficulty associated with exercise and providing feedback while using elastic resistance. Using an LC is as effective as supervised training and could provide value in a clinical setting when patients are working unsupervised.

The effects of a pilates-aerobic program on maximum exercise capacity of adult women

ABSTRACT Introduction: Physical exercise such as the Pilates method offers clinical benefits on the aging process. Likewise, physiologic parameters may be improved through aerobic exercise. Methods: In order to compare the differences of a Pilates-Aerobic intervention program on physiologic parameters such as the maximum heart rate (HRmax), relative maximal oxygen consumption (relative VO2max) and absolute (absolute VOmax), maximum heart rate during maximal oxygen consumption (VO2max-HRmax), maximum minute volume (VE) and forced vital capacity (FVC), a total of 64 adult women (active group = 48.1 ± 6.7 years; control group = 47.2 ± 7.4 years) participated in the study. The physiological parameters, the maximal speed and total duration of test were measured by maximum exercise capacity testing through Bruce protocol. The HRmax was calculated by a cardio-ergometric software. Pulmonary function tests, maximal speed and total time during the physical test were performed in a treadmill (Medisoft, model 870c). Likewise, the spirometry analyzed the impact on oxygen uptake parameters, including FVC and VE. Results: The VO2max (relative and absolute), VE (all, P<0.001), VO2max-HRmax (P<0.05) and maximal speed of treadmill test (P<0.001) showed significant difference in the active group after a physical exercise interventional program. Conclusion: The present study indicates that the Pilates exercises through a continuous training program might significantly improve the cardiovascular system. Hence, mixing strength and aerobic exercises into a training program is considered the optimal mechanism for healthy aging.

Improved skeletal muscle mass and strength after heavy strength training in very old individuals

Age-related loss of muscle mass and function represents personal and socioeconomic challenges. The purpose of this study was to determine the adaptation of skeletal musculature in very old individuals (83+ years) performing 12weeks of heavy resistance training (3×/week) (HRT) compared to a non-training control group (CON). Both groups received similar protein supplementations. We studied 26 participants (86.9±3.2 (SD) (83-94, range) years old) per-protocol. Quadriceps cross-sectional area (CSA) differed between groups at post-test (P<0.05) and increased 1.5±0.7cm² (3.4%) (P<0.05) in HRT only. The increase in CSA is correlated inversely with the baseline level of CSA (R²=0.43, P<0.02). Thigh muscle isometric strength, isokinetic peak torque and power increased significantly only in HRT by 10-15%, whereas knee extension one-repetition maximum (1 RM) improved by 91%. Physical functional tests, muscle fiber type distribution and size did not differ significantly between groups. We conclude that in protein supplemented very old individuals, heavy resistance training can increase muscle mass and strength, and that the relative improvement in mass is more pronounced when initial muscle mass is low.

An Investigation into the Relation between the Technique of Movement and Overload in Step Aerobics

The aim of this research was to determine the features of a step workout technique which may be related to motor system overloading in step aerobics. Subjects participating in the research were instructors (n = 15) and students (n = 15) without any prior experience in step aerobics. Kinematic and kinetic data was collected with the use of the BTS SMART system comprised of 6 calibrated video cameras and two Kistler force plates. The subjects' task was to perform basic steps. The following variables were analyzed: vertical, anteroposterior, and mediolateral ground reaction forces; foot flexion and abduction and adduction angles; knee joint flexion angle; and trunk flexion angle in the sagittal plane. The angle of a foot adduction recorded for the instructors was significantly smaller than that of the students. The knee joint angle while stepping up was significantly higher for the instructors compared to that for the students. Our research confirmed that foot dorsal flexion and adduction performed while stepping up increased load on the ankle joint. Both small and large angles of knee flexion while stepping up and down resulted in knee joint injuries. A small trunk flexion angle in the entire cycle of step workout shut down dorsal muscles, which stopped suppressing the load put on the spine.

Physical exercises with free weights and elastic bands can improve body composition parameters in postmenopausal women: WEB protocol with a randomized controlled trial

OBJECTIVE

The aim of this study was to assess the impact of a program of supervised physical exercises (WEB protocol) versus home-based exercises on body composition (lean mass and fat mass) in postmenopausal women.

METHODS

The initial sample comprised 60 women who were randomized into two groups. After exclusion, the final randomized sample included a supervised group (n = 16; mean age, 66.4 ± 6.5 y) and a home group (n = 18; mean age, 68.2 ± 6.0 y). Both groups underwent a 12-month intervention with physical exercises, including muscle impact exercises and strength and stretching consisting of two weekly sessions of 60 minutes. Body composition was determined by densitometry.

RESULTS

The supervised group exhibited increased lean mass in the upper limbs (P = 0.003) and lower limbs (P = 0.011), total lean tissue (P = 0.015), and appendicular lean mass index (P = 0.001) compared with baseline. The home group exhibited no differences in the lean mass assessments.

CONCLUSIONS

Our results suggest that regular supervised physical exercises with free weights and elastic bands can promote greater improvements in lean body mass than unsupervised exercises in postmenopausal women.

Does Intrasession Concurrent Strength and Aerobic Training Order Influence Training-Induced Explosive Strength and V[Combining Dot Above]O2max in Prepubescent Children?

Alves, AR, Marta, C, Neiva, HP, Izquierdo, M, and Marques, MC. Does intrasession concurrent strength and aerobic training order influence training-induced explosive strength and V[Combining Dot Above]O2max in prepubescent children?. J Strength Cond Res 30(12): 3267-3277, 2016-The aim of this study was to analyze the interference of strength and aerobic training order over an 8-week period on explosive skills and maximal oxygen uptake (V[Combining Dot Above]O2max) in prepubescent children. One hundred twenty-eight prepubescent children aged 10-11 years (10.9 ± 0.5 years) were randomly selected and assigned to 1 of the 3 groups: intrasession concurrent aerobic before (GAS: n = 39) or after strength training (GSA: n = 45) or control group (GC: n = 44; no training program). The GC maintained their baseline level performance, and training-induced differences were found in the experimental groups. Increases were found in the 1-kg and 3-kg medicine ball throws: GAS: +3%, +5.5%, p ≤ 0.05, p < 0.001; GSA: +5.7%, +8.7%, p < 0.001, respectively; in the counter movement jump height and standing long jump length: GAS: +6.5%, +3.4%, p ≤ 0.05; GSA: +7%, +4.5%, p < 0.001, respectively; in the 20-m shuttle-run time: GAS: +2.3%; GSA: +4.6%, p < 0.001; and, in the V[Combining Dot Above]O2max: GAS: +7.3%, p < 0.001; GSA: +3.8%, p < 0.001 from pretraining to post-training. All programs were effective, but GSA produced better results than GAS for muscle strength variables, and GAS produced better results than GSA for aerobic capacity variables. The present study explored an unknown issue and added useful information to the literature in this area. These training methods should be taken into consideration to optimize explosive strength and cardiorespiratory fitness training in school-based programs and sports club programs.

Bench press and push-up at comparable levels of muscle activity results in similar strength gains

Electromyography (EMG) exercise evaluation is commonly used to measure the intensity of muscle contraction. Although researchers assume that biomechanically comparable resistance exercises with similar high EMG levels will produce similar strength gains over the long term, no studies have actually corroborated this hypothesis. This study evaluated EMG levels during 6 repetition maximum (6RM) bench press and push-up, and subsequently performed a 5-week training period where subjects were randomly divided into 3 groups (i.e., 6RM bench press group, 6RM elastic band push-up group, or control group) to evaluate muscle strength gains. Thirty university students with advanced resistance training experience participated in the 2-part study. During the training period, exercises were performed using the same loads and variables that were used during the EMG data collection. At baseline, EMG amplitude showed no significant difference between 6RM bench press and band push-up. Significant differences among the groups were found for percent change (Δ) between pretest and posttest for 6RM (p = 0.017) and for 1 repetition maximum (1RM) (p < 0.001). Six repetition maximum bench press group and 6RM elastic band push-up group improved their 1RM and 6RM (Δ ranging from 13.65 to 22.21) tests significantly with similar gains, whereas control group remains unchanged. Thus, when the EMG values are comparable and the same conditions are reproduced, the aforementioned exercises can provide similar muscle strength gains.

Muscle activity levels in upper-body push exercises with different loads and stability conditions

BACKGROUND

Exercises that aim to stimulate muscular hypertrophy and increase neural drive to the muscle fibers should be used during rehabilitation. Thus, it is of interest to identify optimal exercises that efficiently achieve high muscle activation levels.

OBJECTIVE

The purpose of this study was to compare the muscle activation levels during push-up variations (ie, suspended push-ups with/without visual input on different suspension systems, and push-ups on the floor with/without additional elastic resistance) with the bench press exercise and the standing cable press exercise both performed at 50%, 70%, and 85% of the 1-repetition maximum.

METHODS

Young fit male university students (N = 29) performed 3 repetitions in all conditions under the same standardized procedures. Average amplitude of the electromyogram (EMG) root mean square for the rectus abdominis, external oblique, sternocostal head of the pectoralis major, anterior deltoid, long head of the triceps brachii, upper trapezius, anterior serratus, and posterior deltoid was recorded. The EMG signals were normalized to the maximum voluntary isometric contraction. The EMG data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc.

RESULTS AND CONCLUSIONS

Elastic-resisted push-ups induce similar EMG stimulus in the prime movers as the bench press at high loads while also providing a greater core challenge. Suspended push-ups are a highly effective way to stimulate abdominal muscles. Pectoralis major, anterior deltoid, and anterior serratus are highly elicited during more stable pushing conditions, whereas abdominal muscles, triceps brachii, posterior deltoid, and upper trapezius are affected in the opposite manner.

Can a single session of a community-based group exercise program combining step aerobics and bodyweight resistance exercise acutely reduce blood pressure?

This study aimed to analyze the acute effects of a single session of a community-based group exercise program combining step aerobics and bodyweight resistance exercise on blood pressure in healthy young adult women. Twenty-three healthy young adult women (aged 31.57 ± 7.87 years) participated in two experimental sessions (exercise and control) in a crossover study design. Blood pressure was monitored before, immediately after and at 10, 20 and 30 min of recovery. The exercise session consisted of four phases: 1) a warm-up (5 min of dance aerobics); 2) aerobic exercise training (30 min of step aerobics); 3) resistance exercise training (six sets of 12 repetitions of three bodyweight exercises in a circuit mode, 10 min); and 4) a cool-down (5 min of breathing and flexibility exercises); totaling 50 min of duration. Systolic blood pressure after exercise was significantly lower compared to control at the 10th min (−10.83 ± 2.13 vs. −2.6 ± 2.13 mmHg; p = 0.009), 20th min (−11.26 ± 2.13 vs. −3.04 ± 2.13 mmHg; p = 0.009) and 30th min of recovery (−10.87 ± 2.39 vs. −0.48 ± 2.39 mmHg; p = 0.004). A single session of a community-based group exercise program combining step aerobics and bodyweight resistance exercise was effective in inducing significant post-exercise hypotension in healthy young adult women. This type of low-cost exercise interventions may have an important role in the prevention of cardiovascular diseases and in community health promotion.

Effect of concurrent training, flexible nonlinear periodization, and maximal-effort cycling on strength and power

Although there is considerable research on concurrent training, none has integrated flexible nonlinear periodization and maximal-effort cycling in the same design. The purpose of this investigation was to test outcome measures of strength and power using a pretest-posttest randomized groups design. A strength and endurance (SE) group was compared with a strength, endurance, and maximal-effort cycling (SEC) group. Both groups used a flexible nonlinear periodization design. Thirteen male and 7 female students (mean ± SD: age, 22.5 ± 4.1 years; height, 173.5 ± 12.4 cm; weight, 79.4 ± 20.2 kg; strength training experience, 2.4 ± 2.2 years) participated in this study. Groups were not matched for age, height, weight, strength training experience, or sex, but were randomly assigned to an SE (n = 10) or SEC (n = 10) group. All training was completed within 45 minutes, twice per week (Monday and Wednesday), over 12 consecutive weeks. Both groups were assigned 6.75 total hours of aerobic conditioning, and 13.5 hours of free weight and machine exercises totaling 3,188 repetitions ranging from 5 to 20 repetition maximums. The SEC group performed 2 cycling intervals per workout ranging from 10 to 45 seconds. Pretest and posttest measures included chest press and standing broad jump. Analysis of variance showed that there were no significant differences between the SE and SEC groups on measures of chest press or standing broad jump performance (p, not significant). Paired sample t-tests (p = 0.05) showed significant improvement in strength and power in all groups (pretest to posttest), except for SE jump performance (p, not significant). In conclusion, adding maximal-effort cycling does not provide additional strength or power benefits to a concurrent flexible nonlinear training program. However, an exercise professional can take confidence that a concurrent flexible nonlinear training program can increase strength and power in healthy individuals.

Resistance exercise and aerobic exercise when paired with dietary energy restriction both reduce the clinical components of metabolic syndrome in previously physically inactive males

The purpose of this study was to compare resistance exercise training (RT) to aerobic exercise training (AE) on the clinical risk factors for metabolic syndrome (MetSyn) in physically inactive overweight males (age 27-48 years). Subjects with at least one risk factor for MetSyn performed RT (n = 13, age 35.1 ± 4.7 years, BMI 31.2 ± 2.7 kg/m(2)) or AE (n = 9, age 37.6 ± 4.9 years, BMI, 31.2 ± 3.2 kg/m(2)) for 6 months. Training frequency and exercise session duration were equal and by 3 months the subjects exercised 4 day/week for 45 min/session. Blood lipids and glucose, waist circumference, and mean arterial blood pressure (MAP) were measured at 0, 3, and 6 months. A MetSyn z score was calculated for each subject from triglycerides, HDL cholesterol, fasting glucose, waist circumference, and MAP. Statistical significance was set at p ≤ 0.05. No significant differences existed between RT and AE groups at 0 month. AE showed a significant reduction in MetSyn z score from 0 (0.91 ± 3.57) to 6 months (-1.35 ± 2.95), while RT approached significance (p = 0.07) from 0 (0.09 ± 2.62) to 6 months (-1.30 ± 2.22). Triglycerides (mmol/L) significantly decreased in AE from 0 (1.93 ± 0.90) to 6 months (1.41 ± 0.70). Waist circumference (cm) significantly decreased in AE from 0 (106.8 ± 7.3) to 6 months (101.2 ± 6.5), and in RT from 0 (108.4 ± 9.0) to 6 months (105.7 ± 7.0). MAP (mmHg) decreased in RT from 0 (93.8 ± 5.8) to 6 months (87.5 ± 6.1) and in AE from 0 (97.6 ± 7.0) to 6 months (91.3 ± 6.8). With equal training frequency and exercise session duration, both RT and AE training, when paired with energy restriction improve the clinical risk factor profile for MetSyn.

Sex differences in "weightlifting" injuries presenting to United States emergency rooms

Benefits of resistance training include improved muscle strength and sports performance and may include reduced injuries. However, few studies have examined sex differences in resistance training-related injuries. The objective of this investigation was to evaluate sex differences in injuries associated with strength training in adolescents and young adults by type (sprains and strains, fractures), mechanism (accidental, nonaccidental), and location (head, trunk, arm, hand, leg, foot) of injury. We hypothesized that there would be sex differences in type, mechanism, and location of strength training injuries. The U.S. Consumer Product Safety Commission (CPSC) National Electronic Injury Surveillance System (NEISS) was queried from 2002 to 2005 using the CPSC code for "Weightlifting." Subjects between the ages of 14 and 30 years were included in the study. CPSC sampling weights were used to calculate national estimates from the sample of 3,713 patients (men = 3,102; women = 611). Weighted Chi-square analyses were used to compare differences in mechanism, type, and location of injury for men versus women. Men had significantly more sprains and strains (p = 0.004), whereas women demonstrated increased accidental injuries compared to men (p < 0.001). The trunk was the most commonly injured body part for both men (36.9%) and women (27.4%). Men had more trunk injuries than women (p < 0.001), whereas women had more foot (p < 0.001) and leg (p = 0.03) injuries than men (p < 0.001). The findings indicate that men may suffer more exertional-type resistance injuries during strength training (sprains and strains) compared to women, especially at the trunk. Conversely, women may be more susceptible to lower-extremity injuries resulting from accidents during resistance training.

Effects of aquatic resistance training on health and fitness in postmenopausal women

To investigate effects of 24 weeks of resistance training with aquatic resistance devices or elastic bands (EB) on markers of cardiovascular health and physical capacity. Forty-six healthy, sedentary postmenopausal women participated. The groups were aquatic exercise (AE; n = 15), EB (n = 21), and control (n = 10). Venous blood chemistry included cholesterol, triglycerides, glucose, and apolipoprotein B. Physical capacity was assessed by the sit-and-reach, knee push-up, 60-s squat, and abdominal crunch tests. Both AE and EB, respectively, showed a significant (P <or= 0.05) decrease in body fat (14.56, 11.97%) and diastolic blood pressure (8.03, 5.88%), and a significant increase in fat-free mass (2.88, 1.22%), sit-and-reach (27.94, 44.2%), knee push-ups (84.74, 51.59%), and 60-s squats (65.76, 46.04%). AE also showed a significant increase in abdominal crunches (28.11%). Aquatic resistance training can offer significant physiological benefits in health and performance that are comparable to those obtained from EB in this population.

Good maintenance of physical benefits in a 12-month exercise and nutritional intervention by voluntary, home-based exercise: a 6-month follow-up of a randomized controlled trial

We assessed the maintenance of physical benefits in a 12-month exercise and nutritional intervention in postmenopausal women (55-75 years of age) after 6-month postintervention follow-up by voluntary, home-based exercise, and examined whether physical factors responded differently to high or low exercise frequency during the 6-month postintervention period. Forty-five women completed the 12-month intervention program, followed by 6-month cessation of intervention, and were compared with 19 matched controls. Twenty-one of the former exercisers reported that they continued exercise training at least 30 min at least 3 days/week (high-frequency exerciser, HFE), while the remaining 24 former exercisers reported that they had done exercise training at least 30 min twice per week or less during the postintervention follow-up (low-frequency exerciser, LFE). The following items were measured at baseline, 12, and 18 months: bone strength, CS-30 test, 10-m obstacle walk, whole-body reaction time, one-leg stance, and grip strength. After 6-month postintervention follow-up, the beneficial effect on bone was not fully maintained. These benefits in physical performance obtained in the 12-month intervention program, except one-leg stance, were fully maintained for 6 months by voluntary, home-based exercise. The gained benefit in one-leg stance was not fully maintained; LFE showed a significant decrease over the 6-month postintervention follow-up period, suggesting that continued exercise training of at least 30 min at least 3 days/week is required to maintain the balance benefit. These findings suggest that a continued exercise program of voluntary, home-based exercise may be effective to maintain the physical benefits of exercise intervention that may lower fracture risk in later life.

Physical activity level and health-related quality of life in the general adult population: a systematic review

OBJECTIVE

Little is known regarding health-related quality of life and its relation with physical activity level in the general population. Our primary objective was to systematically review data examining this relationship.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL, and PsycINFO for health-related quality of life and physical activity related keywords in titles, abstracts, or indexing fields.

RESULTS

From 1426 retrieved references, 55 citations were judged to require further evaluation. Fourteen studies were retained for data extraction and analysis; seven were cross-sectional studies, two were cohort studies, four were randomized controlled trials and one used a combined cross sectional and longitudinal design. Thirteen different methods of physical activity assessment were used. Most health-related quality of life instruments related to the Medical Outcome Study SF-36 questionnaire. Cross-sectional studies showed a consistently positive association between self-reported physical activity and health-related quality of life. The largest cross-sectional study reported an adjusted odds ratio of "having 14 or more unhealthy days" during the previous month to be 0.40 (95% Confidence Interval 0.36-0.45) for those meeting recommended levels of physical activity compared to inactive subjects. Cohort studies and randomized controlled trials tended to show a positive effect of physical activity on health-related quality of life, but similar to the cross-sectional studies, had methodological limitations.

CONCLUSION

Cross-sectional data showed a consistently positive association between physical activity level and health-related quality of life. Limited evidence from randomized controlled trials and cohort studies precludes a definitive statement about the nature of this association.

Exercise effects on bone mineral density in women with breast cancer receiving adjuvant chemotherapy

PURPOSE/OBJECTIVES

To test the effects of aerobic and resistance exercise on changes in bone mineral density (BMD) in women newly diagnosed with stage I-III breast cancer receiving chemotherapy.

DESIGN

Randomized clinical trial.

SETTING

Two National Cancer Institute-designated cancer centers in metropolitan areas.

SAMPLE

66 women with stage I-III breast cancer beginning adjuvant chemotherapy.

METHODS

Participants were randomized to aerobic or resistance exercise and usual care. At the beginning of chemotherapy and at six months, patients completed exercise testing and BMD assessment of the lumbar spine by dual energy x-ray absorptionetry.

MAIN RESEARCH VARIABLES

BMD, aerobic capacity, and muscle strength.

FINDINGS

The average decline in BMD was -6.23% for usual care, -4.92% for resistance exercise, and -0.76% for aerobic exercise. Aerobic exercise preserved BMD significantly better compared to usual care. Premenopausal women demonstrated significantly greater declines in BMD than postmenopausal women. Aerobic capacity increased by almost 25% for women in the aerobic exercise group and 4% for resistance exercise. Participants in the usual care group showed a 10% decline in aerobic capacity.

CONCLUSIONS

The data suggest that weight-bearing aerobic exercise attenuates declines in BMD and that aerobic and resistance exercise improve aerobic capacity and muscle strength at a time when women generally show marked declines in functional ability.

IMPLICATIONS FOR NURSING

Exercise may prevent or at least minimize bone loss observed during chemotherapy and may prevent or delay the long-term effects of osteoporosis.

Effect of adding exercise to a diet containing glucomannan

The aim of this study was to examine the effect of adding a total-body exercise program to an 8-week diet supplemented with glucomannan on weight loss, body composition, blood parameters, and physical performance in overweight men and women. Sedentary men and women who were overweight (body mass index>25 kg m(-2)) (men: 18-57 years, 27.0+/-11.2 years, 177.5+/-7.6 cm, 102.4+/-14.9 kg; women: 18-52 years, 33.4+/-12.1 years, 160.6+/-4.6 cm, 79.9+/-9.3 kg) completed an 8-week diet with 3000 mg glucomannan combined with either no exercise (No-Ex) (10 men, 10 women) or a resistance and endurance exercise training program (Ex) (12 men, 10 women). The diet emphasized healthy food choices and portion size control. The exercise training consisted of 3 weekly sessions of approximately 1 hour of a nonlinear periodized total-body resistance exercise program followed by 30 minutes of endurance exercise. After the intervention, there were reductions (P<.05) in body mass (men, -2.7+/-1.4 and -3.0+/-4.0 kg; women, -2.2+/-1.5 and -3.3+/-1.5 kg; No-Ex and Ex, respectively), fat mass (men, -2.3+/-1.6 and -3.9+/-2.5 kg; women, -2.6+/-1.4 and -3.6+/-1.1 kg; No-Ex and Ex, respectively), total cholesterol (TC) (men, -17.9+/-21.5 and -18.8+/-19.4 mg dL(-1); women, -9.3+/-20.0 and -10.1+/-19.5 mg dL(-1); No-Ex and Ex, respectively), and low-density lipoprotein cholesterol. Exercise significantly improved high-density lipoprotein cholesterol (HDL-C) (No-Ex, -2.0+/-4.7 and -2.3+/-4.5 mg dL(-1) vs Ex, 4.4+/-10.8 and 1.6+/-3.6 mg dL(-1); men and women, respectively), TC/HDL-C ratio, squat and bench press 1-repetition maximum, and distance covered during a shuttle-run test. In addition, exercise appeared to augment the reduction in fat mass (by 63% and 50%; men and women, respectively) and waist circumference, but did not affect total weight loss. Addition of a resistance and endurance exercise training program to a glucomannan diet regimen significantly improved measures of body composition, HDL-C, and TC/HDL-C ratio.

The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans

Strength training is an important component in sports training and rehabilitation. Quantification of the dose-response relationships between training variables and the outcome is fundamental for the proper prescription of resistance training. The purpose of this comprehensive review was to identify dose-response relationships for the development of muscle hypertrophy by calculating the magnitudes and rates of increases in muscle cross-sectional area induced by varying levels of frequency, intensity and volume, as well as by different modes of strength training. Computer searches in the databases MEDLINE, SportDiscus and CINAHL were performed as well as hand searches of relevant journals, books and reference lists. The analysis was limited to the quadriceps femoris and the elbow flexors, since these were the only muscle groups that allowed for evaluations of dose-response trends. The modes of strength training were classified as dynamic external resistance (including free weights and weight machines), accommodating resistance (e.g. isokinetic and semi-isokinetic devices) and isometric resistance. The subcategories related to the types of muscle actions used. The results demonstrate that given sufficient frequency, intensity and volume of work, all three types of muscle actions can induce significant hypertrophy at an impressive rate and that, at present, there is insufficient evidence for the superiority of any mode and/or type of muscle action over other modes and types of training. Tentative dose-response relationships for each variable are outlined, based on the available evidence, and interactions between variables are discussed. In addition, recommendations for training and suggestions for further research are given.

Site-specific response of bone to exercise in premenopausal women

We studied the response of bone at specific skeletal sites to either lower body exercise alone or complemented with upper body exercise in premenopausal women. Thirty-five exercisers and 24 age-matched controls completed the 12-month study. Exercising women (N = 35) were randomly assigned to either lower body resistance plus jump exercise (LOWER) (N = 19) or to lower and upper body resistance plus jump exercise (UPPER + LOWER) (N = 16). Exercisers trained three times per week completing 100 jumps and 100 repetitions of lower body resistance with or without 100 repetitions of upper body resistance exercise at each session. Intensity for lower body exercise was increased using weighted vests for jump and resistance exercises, respectively. Intensity for upper body exercise was increased using greater levels of tautness in elastic bands. Bone mineral density (BMD) at the total hip, greater trochanter, femoral neck, lumbar spine and whole body were measured by dual energy X-ray absorptiometry (Hologic QDR-1000/W) at baseline, 6 and 12 months. Data were analyzed first including all enrolled participants who completed follow-up testing and secondly including only those women whose average attendance was > or =60% of prescribed sessions. Group differences in 12-month %change scores for BMD variables were analyzed by univariate ANCOVA adjusted for baseline differences in age. Post hoc tests were performed to determine which groups differed from one another. Initial analysis showed significant differences in greater trochanter BMD between each exercise group and controls, but not between exercise groups (2.7%+/-2.5% and 2.2%+/-2.8% vs. 0.7%+/-1.7%, for LOWER and UPPER + LOWER vs. controls, respectively; p < 0.02) and near significant group differences at the spine (p = 0.06). Excluding exercisers with low compliance, group differences at the greater trochanter remained, while spine BMD in UPPER + LOWER was significantly different from LOWER and controls, who were not significantly different from one another (1.4%+/-3.9% vs. -0.9%+/-1.7% and -0.6%+/-1.8%, for UPPER + LOWER vs. LOWER and controls, respectively; p < 0.05). No significant differences among groups were found for femoral neck, total hip or whole body BMD. Our data support the site-specific response of spine and hip bone density to upper and lower body exercise training, respectively. These data could contribute to a site-specific exercise prescription for bone health.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Type and intensity of activity and risk of mobility limitation: the mediating role of muscle parameters

OBJECTIVES

To investigate the association between different types of physical activity behavior and incident mobility limitation in older men and women and to examine whether muscle parameters mediate these associations.

DESIGN

Cohort study with 4.5-year follow-up.

SETTING

Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. A random sample of white Medicare beneficiaries and all age-eligible blacks.

PARTICIPANTS

Three thousand seventy-five black and white men and women aged 70 to 79 with no self-reported difficulty walking one-quarter of a mile or climbing 10 steps, enrolled in the Health, Aging and Body Composition (Health ABC) Study.

MEASUREMENTS

Participants were classified as exercisers (reporting > or = 1,000 kcal/wk of exercise activity), lifestyle active (reporting < 1,000 kcal/wk of exercise activity and > or = 2,719 kcal/wk of total physical activity), or inactive (reporting < 1,000 kcal/wk of exercise activity and < 2,719 kcal/wk of total physical activity). The study outcome, incident mobility limitation, was defined as two consecutive, semiannual self-reports of any difficulty walking one quarter of a mile or climbing 10 steps. Thigh muscle area, thigh muscle attenuation (a marker of fat infiltration in muscle), appendicular lean soft tissue mass, and isokinetic knee extensor strength were examined as potential mediators.

RESULTS

Over 4.5 years, 34.3% of men and 47.4% of women developed mobility limitation. Inactive persons had twice the risk of incident mobility limitation as exercisers (hazard ratio (HR)=2.08, 95% confidence interval (CI)=1.60-2.70, for men, HR=1.98, 95% CI=1.51-2.60, for women). Lifestyle-active men and women had an intermediate risk (HR=1.47 and 1.44, respectively). For the lifestyle active and inactive, absence of walking activity conferred an additional risk of mobility limitation. Muscle parameters did not mediate the relationship between physical activity and mobility limitation, except for knee extensor strength in men.

CONCLUSION

Exercise and an active lifestyle that includes walking protect against mobility loss in older men and women. Activity effects on muscle parameters do not explain this association.

Validation of the Children???s OMNI-Resistance Exercise Scale of Perceived Exertion

PURPOSE

This investigation examined concurrent validity of the Children's OMNI-Resistance Exercise Scale (OMNI-RES) of perceived exertion for 10- to 14-yr-old females (N = 25) and males (N = 25) performing unilateral biceps curl (BC) and knee extension (KE) isotonic exercises.

METHODS

The criterion variable was total weight lifted (Wt(tot)), determined separately for females and males during BC and KE. Subjects performed three separate sets of 6, 10, and 14 repetitions for BC and KE at 50% 1-RM. Ratings of perceived exertion for the active muscles (RPE-AM) and overall body (RPE-Overall) were measured during the final repetition.

RESULTS

For both female and male groups across the three sets: (a) RPE-AM ranged from 2.9 to 8.3 for BC and 4.5 to 9.6 for KE, and (b) RPE-O ranged from 1.9 to 7.0 for BC and 3.6 to 7.7 for KE. Positive linear regression coefficients ranged from r = 0.72 to 0.88 (P < 0.01) between Wt(tot) and RPE-AM and RPE-Overall for BC and KE in both gender groupings. RPE did not differ between females and males at any measurement point within each set for BC and KE. RPE-AM was greater (P < 0.01) than RPE-Overall in the three sets of BC and KE.

CONCLUSION

Findings provided concurrent validation of the Children's OMNI-RES to measure RPE for the active muscle and overall body in 10- to 14-yr-old females and males performing upper and lower body resistance exercise.

Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study

BACKGROUND

Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes.

HYPOTHESIS

Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament.

RESULTS

Nine athletes had a confirmed anterior cruciate ligament rupture; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture. Knee abduction angle (P<.05) at landing was 8 degrees greater in anterior cruciate ligament-injured than in uninjured athletes. Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment (P<.001) and 20% higher ground reaction force (P<.05), whereas stance time was 16% shorter; hence, increased motion, force, and moments occurred more quickly. Knee abduction moment predicted anterior cruciate ligament injury status with 73% specificity and 78% sensitivity; dynamic valgus measures showed a predictive r2 of 0.88.

CONCLUSION

Knee motion and knee loading during a landing task are predictors of anterior cruciate ligament injury risk in female athletes.

CLINICAL RELEVANCE

Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury. The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective, targeted interventions.

Methodological approaches and rationale for training to prevent anterior cruciate ligament injuries in female athletes

Female athletes have a four- to sevenfold increased risk of anterior cruciate ligament (ACL) injury compared with their male counterparts playing at similar levels in the same sports. The elevated risk of ACL injury in females coupled with the geometric increase in female sports participation in the last 30 years has led to a rapid rise in these injuries. This large increase in ACL injury incidence has fueled studies into both mechanisms of injury and interventions to prevent injury. A review of published multidisciplinary approaches demonstrates that several training protocols have utilized multiple components targeted toward injury prevention training and were able to reduce injury incidence in female athletes. Similar training techniques may also be used to gain improvements in measures of performance. The purpose of this review is to highlight training components that may reduce ACL injury risk and assess their potential for combined use in performance-oriented protocols.

Changes in Muscle Hypertrophy in Women with Periodized Resistance Training

PURPOSE

Adaptations of arm and thigh muscle hypertrophy to different long-term periodized resistance training programs and the influence of upper body resistance training were examined.

METHODS

Eighty-five untrained women (mean age = 23.1 +/- 3.5 yr) started in one of the following groups: total-body training [TP, N = 18 (3-8 RM training range) and TH, N = 21 (8-12 RM training range)], upper-body training [UP, N = 21 (3-8 RM training range) and UH, N = 19, (8-12 RM training range)], or a control group (CON, N = 6). Training took place on three alternating days per week for 24 wk. Assessments of body composition, muscular performance, and muscle cross-sectional area (CSA) via magnetic resonance imaging (MRI) were determined pretraining (T1), and after 12 (T2) and 24 wk (T3) of training.

RESULTS

Arm CSA increased at T2 (approximately 11%) and T3 (approximately 6%) in all training groups and thigh CSA increased at T2 (approximately 3%) and T3 (approximately 4.5%) only in TP and TH. Squat one-repetition maximum (1 RM) increased at T2 (approximately 24%) and T3 (approximately 11.5%) only in TP and TH and all training groups increased 1 RM bench press at T2 (approximately 16.5%) and T3 (approximately 12.4%). Peak power produced during loaded jump squats increased from T1 to T3 only in TP (12%) and TH (7%). Peak power during the ballistic bench press increased at T2 only in TP and increased from T1 to T3 in all training groups.

CONCLUSIONS

Training specificity was supported (as sole upper-body training did not influence lower-body musculature) along with the inclusion of heavier loading ranges in a periodized resistance-training program. This may be advantageous in a total conditioning program directed at development of muscle tissue mass in young women.

The effectiveness of worksite physical activity programs on physical activity, physical fitness, and health

OBJECTIVE

To critically review the literature with respect to the effectiveness of worksite physical activity programs on physical activity, physical fitness, and health.

DATA SOURCES

A search for relevant English-written papers published between 1980 and 2000 was conducted using MEDLINE, EMBASE, Sportdiscus, CINAHL, and Psychlit. The key words used involved a combination of concepts regarding type of study, study population, intervention, and outcome measure. In addition, a search was performed in our personal databases, as well as a reference search of the studies retrieved.

STUDY SELECTION

The following criteria for inclusion were used: 1) randomized, controlled trial or nonrandomized, controlled trial; 2) working population; 3) worksite intervention program to promote employees' physical activity or physical fitness; and 4) physical activity, physical fitness, or health-related outcomes.

DATA EXTRACTION

Two reviewers independently evaluated the quality of relevant studies using a predefined set of nine methodological criteria. Conclusions regarding the effectiveness of a worksite physical activity programs were based on a rating system consisting of five levels of evidence.

DATA SYNTHESIS

Fifteen randomized, controlled trials and 11 nonrandomized, controlled trials met the criteria for inclusion and were reviewed. Six randomized, controlled trials and none of the nonrandomized, controlled trials were of high methodological quality. Strong evidence was found for a positive effect of a worksite physical activity program on physical activity and musculoskeletal disorders. Limited evidence was found for a positive effect on fatigue. For physical fitness, general health, blood serum lipids, and blood pressure, inconclusive or no evidence was found for a positive effect.

CONCLUSIONS

To increase the level of physical activity and to reduce the risk of musculoskeletal disorders, we support implementation of worksite physical activity programs. For the other outcome measures, scientific evidence of the effectiveness of such a program is still limited or inconclusive, which is mainly the result of the small number of high-quality trials. Therefore, we recommend performing more randomized, controlled trials of high methodological quality, taking into account criteria such as randomization, blinding, and compliance.

Concurrent validation of the OMNI perceived exertion scale for resistance exercise

The criterion variables were total weight lifted (Wttot ) determined separately for women and men during BC and KE, and blood lactic acid concentration ([Hla]) determined for a combined female ( N = 10) and male ( N = 10) subset during BC. Subjects performed three separate sets of 4, 8, and 12 repetitions for BC and KE at 65% one-repetition maximum. Rating of perceived exertion for the active muscles (RPE-AM) was measured during the mid and final repetition and RPE for the overall body (RPE-O) during the final repetition. : For both female and male groups across the three sets: (a) RPE-AM ranged from 3.6 to 8.2 for BC and 5.1 to 9.6 for KE and (b) RPE-O ranged from 2.4 to 6.7 for BC and 4.2 to 7.6 for KE. Positive linear regressions ranged from r = 0.79 to 0.91 ( P < 0.01) between Wttot and RPE-AM (mid), RPE-AM (final), and RPE-O for both BC and KE in both sex groupings. A positive ( P < 0.01) linear regression was found between [Hla] and RPE-AM (final) (r = 0.87) during BC. RPE did not differ between women and men at any measurement point within each set for BC and KE. RPE-AM (final) was greater ( P < 0.01) than RPE-O in the three sets of BC and KE.

CONCLUSION

Findings provided concurrent validation of the OMNI-RES to measure RPE for the active muscle and overall body in young recreationally trained female and male weight lifters performing upper- and lower-body resistance exercise.