Effects Of Power Training Research Articles

Effects of power training in older patients with multiple sclerosis on neurodegeneration, neuromuscular function, and physical function. A study protocol for the “power training in older multiple sclerosis patients (PoTOMS) randomized control trial

IntroductionApproximately one-third of all persons with multiple sclerosis (pwMS) are older, i.e., having an age ≥60 years. Whilst ageing and MS separately elicit deteriorating effects on brain morphology, neuromuscular function, and physical function, the combination of ageing and MS may pose a particular challenge. To counteract such detrimental changes, power training (i.e., a type of resistance exercise focusing on moderate-to-high loading at maximal intended movement velocity) presents itself as a viable and highly effective solution. Power training is known to positively impact physical function, neuromuscular function, as well as brain morphology. Existing evidence is promising but limited to young and middle-aged pwMS, with the effects of power training remaining to be elucidated in older pwMS. MethodsThe presented ‘Power Training in Older MS patients (PoTOMS)’ trial is a national, multi-center, parallel-group, randomized controlled trial. The trial compares 24 weeks of usual care(n = 30) to 24 weeks of usual care and power training (n = 30). The primary outcome is whole brain atrophy rate. The secondary outcomes include changes in brain micro and macro structures, neuromuscular function, physical function, cognitive function, bone health, and patient-reported outcomes. Ethics and disseminationThe presented study is approved by The Regional Ethics Committee (reference number 1-10-72-222-20) and registered at the Danish Data Protection Agency (reference number 2016-051-000001). All study findings will be published in scientific peer-reviewed journals and presented at relevant scientific conferences independent of the results. The www.clinicaltrials.gov identifier is NCT04762342.

Effects of plyometric jump training versus power training using free weights on measures of physical fitness in youth male soccer players

ABSTRACT This study aimed to contrast the effects of power training (PT) and plyometric-jump-training (PJT) programmes on measures of physical fitness in prepubertal male soccer players. Thirty-three participants were randomly allocated to PT group (n = 11), PJT group (n = 11), and an active control group (CG; n = 11). Before and after 12 weeks of training, tests were performed for the assessment of sprint-speed , change-of-direction (CoD) speed, muscular strength , and aerobic-endurance (AE). Findings indicated significant group×time interaction effects for all sprint-speed intervals, CoD speed, AE, and strength (d = 0.20–0.32). Post-hoc analyses revealed significant, moderate-to-large improvements in all sprint-speed intervals, CoD speed, AE, and muscle strength following PT (ES = 0.71 to 1.38). The PJT induced significant, moderate-to-large enhancements in 10 m, 20 m, and 30 m sprint, CoD speed, and AE (ES = 0.51 to 0.96) with no significant changes for 5 m sprint-speed and muscle strength (ES = 0.71 and 0.16, respectively). No significant pre-post changes were observed for the CG . Overall, PT and PJT are effective means to improve various measures of physical fitness in prepubertal male soccer players. Notably, to additionally improve acceleration and muscle strength, PT has an advantage over PJT.

Effects of Power Training on Physical Activity, Sitting Time, Disability, and Quality of Life in Older Patients With Type 2 Diabetes During the COVID-19 Confinement.

To evaluate the effectiveness of a multicomponent supervised and unsupervised training program focused on muscle power to counteract the potential changes in sedentary behavior, disability, physical activity (PA), and health-related quality of life (HRQoL) caused by the COVID-19 pandemic domiciliary confinement in prefrail older adults with type 2 diabetes mellitus. Thirty-five older adults with type 2 diabetes mellitus were assigned to 2 groups according to their frailty status: exercise training group (prefrail or frail; n = 21; 74.7 [4.5]y; 33.3% male) and control group (robust; n = 14; 73.1 [3.9]y; 42.9% male). The exercise training group followed a multicomponent training program focusing on muscle power: supervised (5wk) and unsupervised (6wk). The primary outcomes, including PA and sitting time, perceived disability, and HRQoL, were assessed at the baseline and after 11weeks. At the end of confinement, there were significant decreases in PA in both groups (P < .05). Thus, sitting time increased more in the control group than in the exercise training group (P < .05). The HRQoL measures remained unchanged. Muscle power training before and during mandatory COVID-19 self-isolation in type 2 diabetes mellitus older adults (1)attenuates the COVID-19 domiciliary confinement-related increase in sitting time and (2)slightly decreases the self-reported levels of disability and maintains HRQoL.

Power Training in Older Adults With Hip Osteoarthritis and Total Hip Arthroplasty

Exercise is often recommended as part of the conservative management of hip osteoarthritis (OA) and total hip arthroplasty (THA) in older adults. The purpose of this review is to summarize recent evidence on power training in these populations. Clinical practice guidelines, systematic reviews, and randomized clinical trials on hip OA and THA in older adults frequently recommend exercise; however, the optimal exercise type, duration, frequency, and intensity remain unknown. There is a lack of studies that specifically examined the effects of power training on these populations. Additional research on the effects of power training on patients with hip OA and THA is therefore warranted.

Effects of power training on quality of life and postural stability in elderly

Introduction: The muscular strength exercises can be an effective intervention to prevent falls and to favor the functional capacity (FC) in the elderly. However, few studies have reported the benefits of power training (PT) and the subjective perception of the elderly on these activities. Objective: to evaluate the repercussions of a power training protocol on functional capacity and subjective health parameters in the elderly. Method: It was a prospective study involving 48 elderly people. Two groups were composed: a power training group (PG) with 22 participants with a mean age of 68.14 (5.46) years and the control group (CG) was composed of 32 elderly individuals aged 68.03 (4.83) years. Health-related quality of life was measured from the Medical Outcomes Study 36 – Item Short-Form Health Survey (SF-36). The FC was measured by the Berg Balance and Time Up and Go tests. The PT was performed 2x/week, with duration of 50 min/session, for 14 weeks (first two weeks of adaptation; first six weeks 3X/10-15 repetitions of 40-50% of the Subjective Perceived Exertion (SPE) / 6 following weeks 3X/6-10 repetitions of 60-70% of the SPE). The CG performed rhythm activities with the same frequency and weekly duration. Result: It was observed favorable results in FC after 14 weeks of power training. There was also a positive evaluation of most sf-36 domains, with emphasis on physical and emotional aspects. However, the perception of the elderly in relation to the pain domain presented negative results. Conclusion: The PT positively influenced the FC, the physical and the emotional aspects of the elderly; negatively affected the pain and maintained the low risk of fall after 12 weeks of intervention, without presenting intercurrences during the intervention.

Six-year Effects Of Power Training On Physical Activity In Older Adults With Type 2 Diabetes

PURPOSE: We examined the effect of power training on long-term changes in physical activity (PA) in older adults with type 2 diabetes (T2D) during a 5-year follow-up of the GREAT2DO randomized control trial. METHODS: 103 participants with T2D and metabolic syndrome (51% male, 67.9 ±5.5 yrs) were randomized to receive power or sham exercise training, 3 times/week for 12 months and followed for another 5 years. During follow-up, the power group was supported to continue, and controls were crossed over to training, but neither group exercised under direct supervision. Total PA was assessed using the Physical Activity Scale for the Elderly and the Homeostasis model assessment: insulin resistance (HOMA2-IR) and glycosylated hemoglobin (HbA1c) were used as indices of IR and glucose homeostasis, respectively. RESULTS: Total PA decreased significantly during the follow-up period (p=0.0001), driven by reductions between 12 and 24 months when full supervision of exercise was withdrawn, followed by relative stability over the next 4 years. Engagement in resistance training (PRT) declined from 76% at 12 months in the original power training group to 43% of those assessed at the 6-year follow-up. Notably, 43% of the original sham group also reported engaging in PRT at 6 years. HbA1c, adjusted for total PA level over the 5 years, and diabetes medication usage were significantly lower at 72 vs. 12 months (p= 0.04), without any effect of original group assignment. However, there was no significant change over the follow-up period for HOMA2-IR, adjusted for PA and medication usage (p= 0.23). CONCLUSION: 5 years after withdrawal of fully supervised power training or sham exercise in initially inactive older adults with T2D, 43% of both groups were engaged in minimally-supervised resistance training in community sites. Although both groups reduced participation in structured exercise after withdrawal of direct supervision at 12 months, stability in Total PA level from 24-72 months along with persistence of PRT in 43% of older adults with diabetes and many progressive co-morbidities is notable and unexpected. We are unaware of any other study of unsupervised PRT in an older clinical cohort in which adherence rates of 43% have been achieved 6 years after initial randomization, accompanied by significant improvements in glucose control.

Adaptations in mechanical muscle function, muscle morphology, and aerobic power to high-intensity endurance training combined with either traditional or power strength training in older adults: a randomized clinical trial.

There is a lack of information on the effects of power training (PT) as an alternative to traditional strength training (TST) during concurrent training (CT) in older individuals. This study aimed to verify the neuromuscular adaptations that occurred following 16-week interventions with two CT models in older men: high-intensity interval training (HIIT) combined with either TST or PT. Thirty-five older men (65.8 ± 3.9years) were randomly assigned into one of two training groups CTS: TST + HIIT (n = 18) or CTP: PT + HIIT (n = 17). CTS performed resistance training at intensities ranging from 65 to 80% of 1RM at slow controlled speed, whereas CTP trained at intensities ranging from 40 to 60% of 1RM at maximal intentional speed. Lower body one-repetition maximum (1RM), isometric rate of force development (RFD), countermovement jump (CMJ) muscle power output, quadriceps femoris muscles thickness (QF MT), and peak oxygen uptake (VO2peak) were assessed before training and after 8 and 16weeks of CT. Groups improved similarly in all primary outcomes (P < 0.05), with mean increases ranging: 1 RM (from 39.4 to 75.8%); RFD (from 9.9 to 64.8%); and CMJ muscle power (from 1.8 to 5.2%). Significant increases (P < 0.05) were observed in all secondary outcomes (QF MT, specific tension and VO2peak) with no differences between groups. CT models were effective for improving maximal and explosive force (1 RM, RFD, and CMJ power), QF MT, and VO2peak. Moreover, despite that using lower loading intensities, PT induced similar adaptations to those of TST.

THE EFFECT OF OLYMPIC LIFTS ON THE EXPLOSIVE POWER OF ELITE LEVEL FOOTBALL PLAYERS

Purpose: The aim of this study was to investigate the effects of strength and power training on explosive power in elite football players. Methods: In this direction, 20 elite players who played football in a football club A team took part in the research. 10 of the participants were experimental group and 10 of them were the control group. In addition to the technical-tactical training, the players in the experimental group received strength and power training with Olympic lifts, and the technical-tactical training was applied to the players in the control group. Anthropometric measurements (age, height, body weight, BMI, percentage of body fat) and motoric field tests (vertical jump test, standing long jump test, 30 m speed test, agility) for the athletes in the experimental and control groups before and after the 6-week study program test). The data were analysed in IBM SPSS 25.0 program. In the analysis of the data obtained from the applied tests, non-parametric tests were applied, Wilcoxon signed rankings test was used for intra-group comparisons and Mann-Whitney U test was used for comparisons between groups. In statistical analysis, the level of significance was determined as p <0.05. Results: As a result of the analysis, it was concluded that strength and power training applied to the experimental group had a positive effect on body weight, BMI and body fat percentage values from anthropometric measurements, vertical jump test, 30-meter speed test, and zig-zag agility test values from motoric field tests. There was a statistically significant difference between body weight, BMI, vertical jump test, 30-meter speed test and zig-zag agility test between experimental and control groups. Conclusions: According to the findings, it was concluded that the training program was effective in explosive power. Article visualizations:

Changes in Cognition and Power Output in Adults Following High-Velocity Circuit Resistance and Treadmill Training

Previous studies report that increases in aerobic capacity produce improvements in cognition. However, the effects of power training on cognitive domains are not well understood. PURPOSE: To compare the effects of high-velocity circuit resistance (CRT), treadmill (TM) training and no exercise (CONT) on cognitive domains and power output in older adults. METHODS: Fifteen subjects (2M, 13F; 71.3 ± 2.5 yr) participated in 12-wks of CRT, TM or CONT. Executive function (EF)/attention, EF, episodic memory, working memory, processing speed and overall cognition were measured by the flanker (FL), dimensional card sort (DCS), picture sequence (PS), list sorting (LS), pattern comparison (PC), and composite score (CS), respectively, using the NIH Cognition Battery. The walking response and inhibition test (WRIT) also assessed EF. A global score (GS) was determined by the WRIT. Aerobic power (AP) was determined from a peak oxygen consumption test, and lower body power (MP) by a chair stand. RESULTS: A between-groups analysis revealed significant decreases in MP (MD= -269.3, SE= 91.6, p=.04) for TM compared to CONT and a decrease approaching significance compared to CRT (MD= -213.7, SE= 81.9, p=.07). There was a significant main effect for AP (p=.05, n2p=.448) with a trend towards an increase for TM compared to CONT (MD=2.4, SE=1.0, p=.09) and CRT compared to CONT (MD=2.5, SE=1.0, p=.07). No significant interactions were present for cognitive measures. Within-group analyses revealed a significant increase in PC (MD=12.6, SE=4.9, p=.04), a decrease in MP (MD=-205.3, SE=56.9, p=.01), and a trend towards an increase in LS (MD=9.8, SE=4.7, p=.08) and GS (MD=33.1, SE=16.2, p=.07) for TM. For CONT, there was a significant decrease in PC (MD=-12.8, SE=4.9, p=.04) and AP (MD=-2.4, SE=.8, p=.02). Correlation analyses revealed a strong positive association between AP and FL (r=.99, p=.008), MP and GS (r=.97, p=.03), and an inverse correlation between MP and AP (r=-.97, p=.03) and MP and FL (r=-.93, p=.02) for CRT. A strong positive correlation was observed for AP and FL (r=.96, p=.03) for TM, and an inverse correlation between MP and FL (r=-.99, p=.04) for CONT. CONCLUSION: TM and CRT resulted in an increase in AP compared to CONT that corresponded to improvements in EF and WRIT performance, however, only TM exhibited significant decreases in MP.

Effects of Power Training on Mobility and Gait Biomechanics in Old Adults with Moderate Mobility Disability: Protocol and Design of the Potsdam Gait Study (POGS)

Background: Walking speed decreases in old age. Even though old adults regularly participate in exercise interventions, we do not know how the intervention-induced changes in physical abilities produce faster walking. The Potsdam Gait Study (POGS) will examine the effects of 10 weeks of power training and detraining on leg muscle power and, for the first time, on complete gait biomechanics, including joint kinematics, kinetics, and muscle activation in old adults with moderate mobility disability. Methods/Design: POGS is a randomized controlled trial with two arms, each crossed over, without blinding. Arm 1 starts with a 10-week control period to assess the reliability of the tests and is then crossed over to complete 25-30 training sessions over 10 weeks. Arm 2 completes 25-30 exercise sessions over 10 weeks, followed by a 10-week follow-up (detraining) period. The exercise program is designed to improve lower extremity muscle power. Main outcome measures are: muscle power, gait speed, and gait biomechanics measured at baseline and after 10 weeks of training and 10 weeks of detraining. Discussion: It is expected that power training will increase leg muscle power measured by the weight lifted and by dynamometry, and these increased abilities become expressed in joint powers measured during gait. Such favorably modified powers will underlie the increase in step length, leading ultimately to a faster walking speed. POGS will increase our basic understanding of the biomechanical mechanisms of how power training improves gait speed in old adults with moderate levels of mobility disabilities.

Effects of power training in mechanical stiffness of the lower limbs in soccer players

ObjectiveThe aim of this study was evaluate whether leg stiffness (Kleg) changes after power training. MethodsForty professional soccer players were divided into 2 groups (20 were assigned to the trained group and 20 to the control group). A quasi-experimental study with pre–post intervention was conducted to estimate Kleg before (period 1) and after a six-week period of power training (period 2). Leg stiffness was measured using a three-dimensional filming method while soccer players ran on a treadmill at 13km/h. The heights of squat jumps (SJ) and countermovement jumps (CMJ) were measured and the pre-stretch augmentation (PSA) was calculated before and after the training period in both groups. ResultsWe found a significant increase in Kleg after the power training program. Significant positive linear relationships between Kleg and SJ height were found in both periods and groups, while CMJ height was not correlated with Kleg in the trained group during period 2. No significant relationships were found between Kleg and PSA in either case. ConclusionsWe concluded that Kleg can change significantly after a short power training program. Based on our results and previous studies, we suggest that these changes could be mainly associated with adaptions at muscle control level.

Comparative Effect of Power Training and High-Speed Yoga on Motor Function in Older Patients With Parkinson Disease

ObjectivesTo compare the effects of power training (PWT) and a high-speed yoga program on physical performances in older patients with Parkinson disease (PD), and to test the hypothesis that both training interventions would attenuate PD symptoms and improve physical performance. DesignRandomized controlled trial. SettingA laboratory of neuromuscular research and active aging. ParticipantsPatients with PD (N=41; mean age ± SD, 72.2±6.5y). InterventionsTwo high-speed exercise interventions (specifically designed yoga program and PWT) were given for 12 weeks (twice a week), and 1 nonexercise control group. Main Outcome MeasuresUnified Parkinson Disease Rating Scale motor score (UPDRSMS), Berg Balance Scale (BBS), Mini-Balance Evaluation Systems Test (Mini-BESTest), Timed Up and Go, functional reach, single leg stance (SLS), postural sway test, 10-m usual and maximal walking speed tests, 1 repetition maximum (RM), and peak power (PPW) for leg press. ResultsFor the posttests, both training groups showed significant improvements (P<.05) in all physical measurements except functional reach on the more affected side, SLS, and postural sway compared with the pretests, and significantly better scores for UPDRSMS, BBS, Mini-BESTest, Timed Up and Go, functional reach on the less affected side, 10-m usual and maximal walking speed tests, 1RM, and PPW than controls, with no differences detected between the yoga program and PWT. ConclusionsBoth the specially designed yoga program and PWT programs can significantly improve physical performance in older persons with PD.

Effects of Traditional Versus Horizontal Inertial Flywheel Power Training on Common Sport-Related Tasks.

This study aimed to analyze the effects of power training using traditional vertical resistance exercises versus direction specific horizontal inertial flywheel training on performance in common sport-related tasks. Twenty-three healthy and physically active males (age: 22.29 ± 2.45 years) volunteered to participate in this study. Participants were allocated into either the traditional training (TT) group where the half squat exercise on a smith machine was applied or the horizontal flywheel training (HFT) group performing the front step exercise with an inertial flywheel. Training volume and intensity were matched between groups by repetitions (5–8 sets with 8 repetitions) and relative intensity (the load that maximized power (Pmax)) over the period of six weeks. Speed (10 m and 20 m), countermovement jump height (CMJH), 20 m change of direction ability (COD) and strength during a maximal voluntary isometric contraction (MVIC) were assessed before and after the training program. The differences between groups and by time were assessed using a two-way analysis of variance with repeated measures, followed by paired t-tests. A significant group by time interaction (p=0.004) was found in the TT group demonstrating a significantly higher CMJH. Within-group analysis revealed statistically significant improvements in a 10 m sprint (TT: −0.17 0.27 s vs. HFT: −0.11 0.10 s), CMJH (TT: 4.92 2.58 cm vs. HFT: 1.55 2.44 cm) and MVIC (TT: 62.87 79.71 N vs. HFT: 106.56 121.63 N) in both groups (p < 0.05). However, significant differences only occurred in the 20 m sprint time in the TT group (−0.04 0.12 s; p = 0.04). In conclusion, the results suggest that TT at the maximal peak power load is more effective than HFT for counter movement jump height while both TT and HFT elicited significant improvements in 10 m sprint performance while only TT significantly improved 20 m sprint performance.

Effects of tapering with light vs. heavy loads on track and field throwing performance.

The purpose of the study was to investigate the effects of power training with light vs. heavy loads during the tapering phases of a double periodized training year on track and field throwing performance. Thirteen track and field throwers aged 16-26 years followed 8 months of systematic training for performance enhancement aiming at 2 tapering phases during the winter and the spring competition periods. Athletes performed tapering with 2 different resistance training loads (counterbalanced design): 7 athletes used 30% of 1 repetition maximum (1RM) light-load tapering (LT), and 6 athletes used the 85% of 1RM heavy-load tapering (HT), during the winter tapering. The opposite was performed at the spring tapering. Before and after each tapering, throwing performance, 1RM strength, vertical jumping, rate of force development (RFD), vastus lateralis architecture, and rate of perceived exertion were evaluated. Throwing performance increased significantly by 4.8 ± 1.0% and 5.6 ± 0.9% after LT and HT, respectively. Leg press 1RM and squat jump power increased more after HT than LT (5.9 ± 3.2% vs. -3.4 ± 2.5%, and 5.1 ± 2.4% vs. 0.9 ± 1.4%, respectively, p ≤ 0.05). Leg press RFD increased more in HT (38.1 ± 16.5%) compared with LT (-2.9 ± 6.7%), but LT induced less fatigue than HT (4.0 ± 1.5 vs. 6.7 ± 0.9, p ≤ 0.05). Muscle architecture was not altered after either program. These results suggest that performance increases similarly after tapering with LT or HT in track and field throwers, but HT leads to greater increases in strength, whole body power, and RFD.

Is power training or conventional resistance training better for function in elderly persons? A meta-analysis

to determine the effects of power training with high movement velocity compared with conventional resistance training with low movement velocity for older community-dwelling people. systematic review of randomised controlled trials. the Cochrane Central Register of Controlled TRIALS, PubMed (Medline), EMBASE, CINAHL, PEDro and Scholar-Google. all randomised or quasi-randomised trials investigating power training with high movement velocity versus conventional resistance training with low movement velocity in elderly persons over the age of 60 years. The primary outcomes were measures of functional outcomes; secondary outcomes were balance, gait, strength, power, muscle volume and adverse effects. eleven trials were identified involving 377 subjects. The pooled effect size for the follow-up values of the functional outcomes was 0.32 in favour of the power training (95% CI 0.06 to 0.57) and 0.38 (95% CI -0.51 to 1.28) for the change value. The pooled effect from three studies for self-reported function was 0.16 in favour of power training (95% CI -0.17 to 0.49). power training is feasible for elderly persons and has a small advantage over strength training for functional outcomes. No firm conclusion can be made for safety.

Effects of Ankle Power Training on Movement Time in Mobility-Impaired Older Women

Reduced abilities to generate power put older adults at risk in situations that demand rapid movements. Slower movement times are associated with greater risk of falling and of being involved in a motor vehicle crash. The purpose of this study was to determine the effects of power training on foot movement time and, secondarily, on ankle strength and power in mobility-impaired older women. Fifty mobility-impaired women (70-88 yr) trained twice per week for 12 wk in one of three groups (weights, elastic bands, or placebo control). All groups performed seated warm-up exercises, followed by either concentric dorsiflexion (DF) and plantarflexion (PF) resistance exercises (weights and bands) performed "as fast as possible" or upper body flexibility exercises (control). Foot reaction/movement time and ankle DF and PF peak torque (30 degrees x s(-1)) and peak power (90 degrees x s(-1)) were measured before and after training. Participants who trained with elastic bands demonstrated improvements in movement time (decreased by 24 ms or 12%, P = 0.003). All groups demonstrated improvements in DF and PF strength and power, which were not statistically different. High-velocity/low-load (elastic bands) training improved movement time, which may have important implications in circumstances when rapid generation of torque is required (e.g., to avoid a fall or prevent a vehicle crash). Elastic bands are relatively inexpensive and provide a practical form of training that could be considered in programs designed for older adults with mobility limitations.

Effects of Power Training on Muscle Thickness of Older Men

Effects of Power Training on Muscle Thickness of Older Men

Effects of Power Training on Muscle Thickness of Older Men

The present study aimed at comparing the effects of traditional resistance training (TRT) and power training (PT) in inducing muscle hypertrophy in older men. Twenty older men (aged between 69 and 76 years) were divided in two groups: TRT training (n=9) and PT training (n=11). The volunteers trained twice a week, during 10 weeks. Both groups performed an equal work output and the same exercises with loads between 40% and 60% of 1 RM. Three sets of eight repetitions of each exercise were performed with rest intervals of 90 s between sets. Muscle thickness was measured by ultrasound at the biceps brachii (BIC) and rectus femoris (RF), using a 12 MHz high resolution scanning probe. An ANCOVA was used to compare post training muscle thickness values between TRT and PT, using baseline values as covariates. According to the results, RF muscle thickness increased only in PT, while BIC muscle thickness increased in both groups, but with larger increases in PT. In conclusion, ten weeks of PT induced muscle hypertrophy of the upper and lower limb muscles in older men. PT training may yield better results in muscle hypertrophy when compared with TRT.

Effects of Power Training on Mechanical Muscle Output in Old and Very Old Elderly Women

Decline in explosive force (i.e. contractile rate of force development RFD) and mechanical muscle power with aging has been reported to correlate with reduced ability to maintain postural control and balance recovery after tripping and to predict falls in community-dwelling old adults. It was therefore recently suggested to develop strength training programmes aimed at maximising maximal muscle power and RFD. Different training protocols have been implemented with older people but no study has been designed as power training with heavy loading (75-80% 1RM) for very old individuals. PURPOSE: To evaluate the effect of low frequency (twice a week), 12-weeks power training with heavy-loading (75-80 % of 1RM) using fast-to-explosive execution of the movements on maximal voluntary contraction (MVC), explosive force characteristics (RFD and impulse) and mechanical muscle power during multi-joint motor tasks in two age-groups of community-dwelling elderly women (TG60, TG80, age-groups 60 and 80, respectively). METHODS: Elderly women from two age-groups, 60 (62.7 2.2 years, n=40) and 80 (81.8 2.7 years, n=25) were randomized (matched) into two training and two control groups (TG60, n=20; TG80, n=12) (CG 60, n=20; CG80, n=13). MVC, RFD, normalized RFD (RFD/MVC) and impulse (during 5 time intervals from onset of contraction separated by 100ms) were obtained during a maximal multi-joint isometric leg press. Mechanical muscle power was assessed in a countermovement jump (CMJ) as jump height, (JH), peak power (Ppeak), velocity and force at Ppeak (Vppeak, Fppeak, respectively). RESULTS: RFD, relative RFD, impulse, MVC, Ppeak, JH, and Vppeak increased with training (between 5 and 50%) in both age-groups whereas no changes occurred in the CG. The gains in RFD, impulse and MVC for TG 80 were of such a magnitude that the difference observed pre intervention with the age-group 60 was abolished after training. CONCLUSION: The present findings indicate that power training with heavy loading is highly effective in inducing adaptive changes in maximal and explosive mechanical muscle output in old and very old healthy women even in the 8th decade of life. Importantly, this training type seems safe and suitable in healthy older adults.

Effects of power training on muscle structure and neuromuscular performance

The present study examines changes in muscle structure and neuromuscular performance induced by 15 weeks of power training with explosive muscle actions. Twenty-three subjects, including 10 controls, volunteered for the study. Muscle biopsies were obtained from the gastrocnemius muscle before and after the training period, while maximal voluntary isometric contractions (MVC) and drop jump tests were performed once every fifth week. No statistically significant improvements in MVC of the knee extensor (KE) and plantarflexor muscles were observed during the training period. However, the maximal rate of force development (RFD) of KE increased from 18,836+/-4282 to 25,443+/-8897 N (P<0.05) during the first 10 weeks of training. In addition, vertical jump height (vertical rise of the center of body mass) in the drop jump test increased significantly (P<0.01). Simultaneously, explosive force production of KE muscles measured as knee moment and power increased significantly; however, there was no significant change (P>0.05) in muscle activity (electromyography) of KE. The mean percentage for myosin heavy chain and titin isoforms, muscle fiber-type distributions and areas were unchanged. The enhanced performance in jumping as a result of power training can be explained, in part, by some modification in the joint control strategy and/or increased RFD capabilities of the KE.