Water training in postmenopausal women: Effect on muscular strength

Abstract

The purpose of this study was to determine the effectiveness of a swimming programme and a calisthenics and resistance water training programme, which included aerobic and resistance components, on muscle strength and body weight in postmenopausal women. Both were carried out over a period of 12 months. Ninety-three subjects were randomly assigned to swimming group (SG; n=29), calisthenics and resistance group (CRG; n=34) and control group (CG; n=30). Mean upper-extremities biokinetic force (MF), power (MP) and work (MW) were measured by a biokinetic swim bench (Biometer Swim Bench, Sport Fahnemann). Maximal isometric forces of the trunk flexors (ITF) and knee extensors (IKE) were measured by an isometric strain-gauge dynamometer (T.K.K. 5402, Takei Scientific Instruments Co. Ltd.). Countermovement jump height (CMJ) was evaluated using the Ergojump Bosco System. Energy consumption was measured using a self-administrated food frequency questionnaire (Sanocare Human Systems L.S., Madrid. Spain). Body mass index (BMI) was also measured. CRG improved significantly (p≤0.05) MF increased by 7.92%, MP by 9.08% and MW by 9.3%. SG and CRG demonstrated a significant decrease in BMI (?2.08 and ?2.75% respectively). SG, CRG and CG showed a significant decrease in ITF (?5.07, ?11.34 and ?24.73% respectively) and IKE (?7.99, ?12.77 and ?29.75% respectively). This decrease was significantly greater in CG compared with SG and CRG. There were no significant changes in CMJ in any group. These results indicate that water exercise has significant implications, improving some health-related components of fitness in postmenopausal women.     

The acute effects of static stretching on peak force,peak rate of force development and muscle activity during single- and multiple-joint actions in older women

Abstract

The present study investigated the acute effects of static stretching on peak force, peak rate of force development and integrated electromyography (iEMG) in 27 older women (65 ± 4 years; 69 ± 9 kg; 157 ± 1 cm; 28 ± 4 kg · m^?2). The participants were tested during two exercises (leg press and knee extension) after two conditions: stretching and control. The data were collected on four days (counterbalanced with a 24-hour rest period). In the stretching condition, the quadriceps muscle was stretched (knee flexion) for three sets of 30 s with 30 s rest intervals. No significant difference was detected for peak force and peak rate of force development during the single- and multiple-joint exercises, regardless of the following interactions: condition (stretching and control) vs. time (pre x post x 10 x 20 x 30 minutes post; P > 0.05) and exercise vs. time (P > 0.05). Additionally, no significant interaction was found for the iEMG activity (condition vs. time; P > 0.05) in the single- and multiple-joint exercises. In conclusion, a small amount of stretching of an agonist muscle (quadriceps) did not affect the peak force, peak rate of force development and EMG activity in older women during single- and multiple-joint exercises.     

核心力量训练对提高女子短跑运动员竞技能力的研究

核心力量是上个世纪90年代末期由康复和健身领域移植到竞技体育训练中的一种新型力量训练理念.它是指位于人体核心部位的肌肉、韧带和结缔组织的力量以及它们之间协作的工作能力.目前核心力量已经引起国内外训练界广泛的关注,备受教练、科研人员的青眛,被业内人士称为体能专项化的桥梁.对山东省田径队6名女子短跑运动员进行24周的核心力量训练,结果表明,6名女运动员的专项形态、专项机能和素质都不同程度地得到提高,专项技术动作也不同程度地得到完善,专项成绩的提高也具有显著性.     

Effects of fast-velocity eccentric resistance training on early and late rate of force development

This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising torque. Twenty healthy men were assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFD_INC) or when normalised relative to MVC (RFD_REL). After eight weeks, TG demonstrated increases in MVC (28%), RFD_INC (0–50 ms: 30%; 50–100 ms: 31%) and RFD_REL (0–50 ms: 29%; 50–100 ms: 32%). Moreover, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFD_INC and RFD_REL obtained at the early phase of rising joint torque.     

Sit-to-stand performance of older adults following strength training

A group of healthy older adults completed an 8-week resistance-training program. For 38 participants (14 men, 24 women; ages 60-90 years; M mass = 73.2 kg, SD = 12.3; M height = 1.65 m, SD = 0.08), pre- and postprogram sit-to-stand performance was analyzed (60 Hz video) focusing on center of mass kinematics surrounding transition. Significant changes were attributed to improved strength. Peak forward, downward, and upward velocities increased (16, 59, and 26%, respectively), and relative transition time was delayed 27%. These behaviors were more similar to those of healthy younger adults. Results also indicated strategy changes. Participants exploited their improved strength, forming a distinctive movement pattern emphasizing stability followed by a brisk rise. These adaptations represent meaningfully improved function in an important daily living activity.     

核心力量训练对我国优秀跳水运动员不同力量形式的实效性研究

通过设计和运用多种形式的核心力量训练手段,对我国20名优秀跳水运动员进行为期8周的核心力量训练,验证其对提高跳水运动员不同形式力量能力的影响效果.结果显示,跳水运动员的弹跳力(原地摸高指标)和平衡稳定性(俯桥指标)都有非常显著的提高(P＜0.05),相对最大力量方面也有明显的进步.其中,跳深跨越和夹球收腿跳等指标并未表现出显著性,但这仅是统计学上的解释,根据这些指标的测试要求,它们带有明显的综合身体素质特征,因而推测训练的即刻效应并不明显.同时,研究进一步指出了核心力量训练的作用原理及跳水运动员核心力量训练的选择取向,预示着核心力量训练应成为该项目运动员体能训练的一个重要组成部分.     

The effects of resistance training volume on osteosarcopenic obesity in older women

The aim of this study was to analyze the effects of resistance training (RT) performed with 1 or 3 sets per exercise on osteosarcopenic obesity (OSO) syndrome parameters in older women. Sixty-two older women (68.0 ± 4.3 years, 26.8 ± 4.4 kg/m²) participated in a 12-week RT program. Participants were randomly assigned into one of the three groups: two training groups that performed either 1 set (G1S, n = 21) or 3 sets (G3S, n = 20) 3 times weekly, or a control group (CG, n = 21). Body composition was assessed by dual X-ray absorptiometry, strength was evaluated by 1 repetition maximum testing. The G3S presented significantly higher strength changes than G1S. The changes for percentage of body fat were higher for G3S compared to G1S. There was no difference in skeletal muscle mass between G3S and G1S, however both training groups displayed greater increases in this outcome compared to CG. There was no effect for bone mineral density. The overall analysis indicated higher (P < 0.05) positive changes for G3S than G1S (composed Z-score: G3S = 0.62 ± 0.40; G1S = 0.11 ± 0.48). The results suggest that a 12-week RT period is effective to improve the risk factors of OSO, and that 3 sets induce higher improvements than a single set.     

Effect of individualized resistance training prescription with heart rate variability on individual muscle hypertrophy and strength responses

Abstract

The aim of the present study was to investigate if resistance training (RT), performed with individualized recovery between sessions (RT-IND), promotes greater gains in strength and muscle mass and reduces the variability on adaptations compared to RT with fixed recovery intervals (RT-FIX). Twenty young men (age 21.9?±?3.3 years) were randomized in the RT-IND and RT-FIX groups. Five days before the beginning of the training, measurements of the root mean square of successive R-R intervals differences (RMSSD) values of each individual were performed to establish the baseline values. Before each RT session, the RMSSD values determined whether the participants from RT-IND protocol were recovered from the previous session. Participants performed the RT session only if RMSSD values had returned to the baseline, otherwise they had to wait for an additional 24?h. RT-FIX performed an RT session every 48?h. Muscle strength was measured by one-maximal repetition (1-RM) test and muscle cross-section area (CSA) of the vastus laterals by ultrasonography were assessed pre- and post-training. 1-RM values increased significantly from pre to post-training for both groups (RT-IND: 30% and RT-FIX: 42%, main time effect, P?<?0001), with no significant difference between groups. Muscle CSA increased significantly from pre to post-training (RT-IND: 15.7% and RT-FIX: 15.8%, main time effect, P?<?0001), with no significant difference between groups. In conclusion, RT-IND did not increase the gains in muscle strength and mass neither reduce the variability in muscle adaptations when compared to the RT-FIX.     

Measuring what matters in isometric multi-joint rate of force development

ABSTRACT

This study aimed to evaluate responsiveness (ability to detect change) of isometric force-time measures to neuromuscular fatigue in resistance-trained participants using two differing protocols that modified both the instructions provided to participants and the duration of the test. Both protocols were completed at two knee joint angles in the isometric squat test. Ten participants volunteered to take part in this study (age: 27.0 ± 4.5 years, strength training experience: 7.7 ± 2.6 years). Isometric peak force (ISqT^peak) and isometric explosive force (ISqT^exp) test protocols were assessed at two joint angles (knee angle 100° and 125°) pre-high intensity strength training, immediately post strength training, 24-h post, 48-h post and analysed for peak and RFD performance. Participants completed eight sets of three repetitions of the back-squat exercise as the high-intensity strength training. Results showed the highest standardised response means (SRM) detected was peak force using the ISqT^peak 100, SRM ?1.97 compared to an SRM of ?1.31 for RFD 200 ms in the ISqT^exp 125. Peak force was the most responsive variable using the ISqT^peak protocol, whereas the ISqT^exp protocol was most responsive for RFD measures. Therefore, ISqT^peak and ISqT^exp test protocols should not be used interchangeably to evaluate RFD variables.     

Effect of vibratory stimulation training on maximal force and flexibility

In this study, we investigated a new method of training for maximal strength and flexibility, which included exertion with superimposed vibration (vibratory stimulation, VS) on target muscles. Twenty‐eight male athletes were divided into three groups, and trained three times a week for 3 weeks in one of the following conditions: (A) conventional exercises for strength of the arms and VS stretching exercises for the legs; (B) VS strength exercises for the arms and conventional stretching exercises for the legs; (C) irrelevant training (control group). The vibration was applied at 44 Hz while its amplitude was 3 mm. The effect of training was evaluated by means of isotonic maximal force, heel‐to‐heel length in the two‐leg split across, and flex‐and‐reach test for body flexion. The VS strength training yielded an average increase in isotonic maximal strength of 49.8%, compared with an average gain of 16% with conventional training, while no gain was observed for the control group. The VS flexibility training resulted in an average gain in the legs split of 14.5 cm compared with 4.1 cm for the conventional training and 2 cm for the control groups, respectively. The ANOVA revealed significant pre‐post training effects and an interaction between pre‐post training and ‘treatment’ effects (P< 0.001) for the isotonic maximal force and both flexibility tests. It was concluded that superimposed vibrations applied for short periods allow for increased gains in maximal strength and flexibility.     

Effects of low volume isometric leg press complex training at two knee angles on force-angle relationship and rate of force development

This study compared knee angle-specific neuromuscular adaptations after two low-volume isometric leg press complex training programmes performed at different muscle lengths. Fifteen young males were divided into two groups and trained three times per week for 6 weeks. One group (n?=?8) performed 5–7 sets of 3 s maximum isometric leg press exercise, with 4?min recovery, with knee angle at 85°?±?2° (longer muscle-tendon unit length; L-MTU). The other group (n?=?7) performed the same isometric training at a knee angle of 145°?±?2° (180°^?=?full extension; shorter muscle-tendon unit length; S-MTU). During the recovery after each set of isometric exercise, participants performed two CMJ every minute, as a form of complex training. Maximum isometric force (MIF) and rate of force development (RFD) were measured over a wide range of knee angles. Countermovement jump (CMJ) performance and maximum half-squat strength (1RM) were also assessed. Training at S-MTU induced a large increase of MIF (22–58%, p?p?p?=?0.001). In contrast, training at L-MTU, resulted in a moderate and similar (≈12.3%, p?=?0.028) improvement of force at all knee angles. CMJ performance and 1RM were equally increased in both groups after training by 10.4%?±?8.3% and 7.8%?±?4.7% (p?相似文献   

The improvement in walking speed induced by resistance training is associated with increased muscular strength but not skeletal muscle mass in older women

Objective: The purpose of the present study was to analyze whether improvements in fast walking speed induced by resistance training (RT) are associated with changes in body composition, muscle quality, and muscular strength in older women. Methods: Twenty-three healthy older women (69.6?±?6.4 years, 64.95?±?12.9?kg, 1.55?±?0.07?m, 27.06?±?4.6?kg/m²) performed a RT program for 8 weeks consisting of 8 exercises for the whole body, 3 sets of 10–15 repetitions maximum, 3 times a week. Anthropometric, body composition (fat-free mass [FFM], skeletal muscle mass [SMM], legs lean soft tissue [LLST], fat mass), knee extension muscular strength (KE1RM), muscle quality index (MQI [KE1RM/LLST]), and 10-meter walking test (10-MWT) were performed before and after the intervention. Results: Significant (P?<?.05) changes were observed from pre- to post-training for FFM (+1.6%), MQI (+7.2%), SMM (+2.4%), LLST (+1.8%), KE1RM (+8.6%), fat mass (?1.4%), and time to perform 10-MWT (?3.7%). The percentage change in 10-MWT was significantly associated with percentage change in MQI (r?=??0.46, P?=?.04) and KE1RM (r?=??0.45, P?=?.04), however not associated percentage of changes in SMM (r?=?0.01, P?=?.97), LLST (r?=??0.22, P?=?.33), and body fat (r?=?0.10, P?=?.66). Conclusion: We conclude that the improvement in the 10-MWT after an 8-week RT program is associated with increases in lower limb muscular strength and muscle quality, but not with muscle mass or body fat changes in older women.     

Effect of time-of-day-specific strength training on maximum strength and EMG activity of the leg extensors in men

In this study, we examined the effects of time-of-day-specific strength training on maximum strength and electromyography (EMG) of the knee extensors in men. After a 10-week preparatory training period (training times 17:00-19:00 h), 27 participants were randomized into a morning (07:00-09:00 h, n = 14) and an evening group (17:00-19.00 h, n = 13). Both groups then underwent 10 weeks of time-of-day-specific training. A matched control group (n = 7) completed all testing but did not train. Unilateral isometric knee extension peak torque (MVC) and one-repetition maximum half-squat were assessed before and after the preparatory training and after the time-of-day-specific training at times that were not training-specific (between 09:00 and 16:00 h). During training-specific hours, peak torque and EMG during MVC and submaximum isometric contraction at 40% MVC were assessed before and after the time-of-day-specific training. The main finding was that a significant diurnal difference (P < 0.01) in peak torque between the 07:00 and 17:00 h tests decreased after time-of-day-specific training in the morning group but not in the evening or control groups. However, the extent of this time-of-day-specific adaptation varied between individuals. Electromyography during MVC did not show any time-of-day-specific adaptation, suggesting that peripheral rather than neural adaptations are the main source of temporal specificity in strength training.     

Effect of time-of-day-specific strength training on maximum strength and EMG activity of the leg extensors in men

Abstract

In this study, we examined the effects of time-of-day-specific strength training on maximum strength and electromyography (EMG) of the knee extensors in men. After a 10-week preparatory training period (training times 17:00–19:00 h), 27 participants were randomized into a morning (07:00–09:00 h, n = 14) and an evening group (17:00–19.00 h, n = 13). Both groups then underwent 10 weeks of time-of-day-specific training. A matched control group (n = 7) completed all testing but did not train. Unilateral isometric knee extension peak torque (MVC) and one-repetition maximum half-squat were assessed before and after the preparatory training and after the time-of-day-specific training at times that were not training-specific (between 09:00 and 16:00 h). During training-specific hours, peak torque and EMG during MVC and submaximum isometric contraction at 40% MVC were assessed before and after the time-of-day-specific training. The main finding was that a significant diurnal difference (P < 0.01) in peak torque between the 07:00 and 17:00 h tests decreased after time-of-day-specific training in the morning group but not in the evening or control groups. However, the extent of this time-of-day-specific adaptation varied between individuals. Electromyography during MVC did not show any time-of-day-specific adaptation, suggesting that peripheral rather than neural adaptations are the main source of temporal specificity in strength training.     

Effects of vibration and exercise training on bone mineral density and muscle strength in post-menopausal women

Abstract

The purpose of this study was to compare the effects of a specific vibration programme with those of combined aerobic and resistance exercise training on bone mineral density (BMD), body composition, and muscular strength in post-menopausal women, over a period of 6 months. Thirty-two healthy, inactive post-menopausal women aged 46–62 years were divided into exercise (n = 10), vibration (n = 13), and control (n = 9) groups. The exercise group participated in a supervised programme of strength training at 70% of one-repetition maximum (1-RM) 2 days a week, and aerobic exercise at 70–85% of maximum heart rate one day a week. The vibration group performed vibration training 3 days a week (9 sets×45–80 s per session, 35–40 Hz, peak-to-peak amplitude of vertical vibration = 1.5 mm) on a vibration platform (NemesTM LCB, Bosco System). The BMD of the lumbar spine (L2–L4) was assessed using dual-energy X-ray absorptiometry, and muscle strength with the 1-RM method at baseline and after 6 months of intervention. The BMD of L2–L4 increased in the exercise group (P < 0.05), remained steady in the vibration group, and decreased in the control group (P < 0.05). Muscular strength of leg-extension and leg-curl exercise improved by 28% and 25.5% (P < 0.01) in the exercise group and by 13% (P < 0.01) and 20.5% (P < 0.001) in the vibration group, respectively. The results indicate that conventional training contributed to the increase in BMD of L2–L4, while the vibration programme helped to maintain BMD in post-menopausal women. Both training programmes were efficient in improving muscle strength.     

上肢力量训练对篮球专项班男生罚球命中率的影响

运用教学实验和比较分析等方法，对上肢力量训练影响篮球罚球命中率进行了研究。结果表明，上肢力量训练对大学专项班学生的罚球命中率有显著性影响，在其他教学条件完全相同的情况下，进行上肢力量训练的学生要比不进行上肢力量训练的学生投篮命中率高得多。     

核心训练在膝关节损伤预防及康复中的作用

通过对核心稳定性概念及其作用的回顾,阐述核心稳定性对膝关节损伤预防和康复的重要作用.为加快膝关节损伤的康复和预防损伤的再发生,提出在膝关节损伤后康复的不同阶段,应有目的性的加强核心稳定性功能训练,为膝关节损伤的预防和治疗提供参考.     

肌力训练减小中年女性腰围的实验研究

健身俱乐部部分中年女会员持续参加半年以上肌力训练后显示：肌力训练对减少中年女性腰围有显著作用，并能达到降体重减体脂的目的，对预防心血管系统疾病，增强体质也有重要作用。