The effects of a high-intensity free-weight back-squat exercise protocol on postural stability in resistance-trained males

The purpose of this study was to investigate the effects of a high-intensity free-weight back-squat exercise on postural stability characteristics in resistance-trained males. Eighteen college-aged (mean ± SD: age = 22.9 ± 2.9 years; height = 175.8 ± 6.4 cm; mass = 86.3 ± 9.3 kg), resistance-trained males performed postural stability testing before and after completing five sets of eight repetitions of back-squat exercises at 80% of one-repetition maximum. A commercial balance testing device was used to assess sway index at pre- and at 0, 5, 10, 15 and 20 min post-exercise. Each balance assessment consisted of four, 20-s static stance conditions: eyes-open firm surface, eyes-closed firm surface, eyes-open soft surface and eyes-closed soft surface. Sway index was greater (P = 0.001–0.020) at Post 0 than at all other time points. No differences (P > 0.05) were observed between any other time phases. Sway index was greater (P < 0.001) for eyes-closed soft surface than all other conditions. These findings revealed sway index for all conditions significantly increased following completion of the back-squat; however, sway index recovered within 5 min of exercise. Higher sway index values as a result of neuromuscular fatigue induced by a back-squat exercise may have performance and injury risk consequences to subsequent activities that rely on postural stability. However, these findings suggest balance impairments may recover in ~5 min following high-intensity lower body resistance exercise.     

The effects of maximal and submaximal arm crank ergometry and cycle ergometry on postural sway

Abstract

This study aimed to determine whether arm crank ergometry (ACE) disturbed postural sway to the same extent as cycle ergometry (CE). Nine healthy, none specifically trained adults undertook posturographic tests before and after five separate exercise trials consisting of: two incremental exercise tests to exhaustion for ACE and CE to examine postural sway responses to maximal exercise and to determine peak power output (W_max); two subsequent tests of 30 min duration for ACE and CE at a relative workload corresponding to 50% of the ergometer-specific W_max (ACE_rel; 53 ± 8 W and CE_rel; 109 ± 16 W). A final CE trial was performed at the same absolute power output (CE_abs) as the submaximal ACE trial to match absolute exercise intensity (i.e., 53 ± 8 W). The centre of pressure (COP) displacement was recorded using a force platform before, immediately after exercise and during a 30-min recovery period. ACE had no effects on postural sway (P > 0.05). An increase in mediolateral COP displacement was observed following maximal CE only (P = 0.001), while anteroposterior COP displacement and COP path length increased following maximal and submaximal CE (P < 0.05). These differences in postural sway according to exercise mode likely stem from the activity of postural muscles when considering that CE recruits lower limb muscles involved in balance. This study provides evidence of an exercise mode which does not elicit post-exercise balance impairments, therefore possesses applications to those at an increased risk of falling.     

Visual and postural control of an arbitrary posture: The handstand

Abstract

The aim of this study was to increase our understanding of postural regulation by analysing an arbitrary posture – the handstand. We assessed the relative influence of peripheral vision and central visual anchoring on the postural balance of gymnasts in the inverted-stand posture. Displacements of the centre of pressure, the angles between the body segments, and the gymnast's height in the handstand were analysed. Postural regulation in the handstand appeared to be organized according to a system similar to that in erect posture, with three articular levels suggesting the existence of a typical organization of human posture. Moreover, both intra-modal (central and peripheral vision) and inter-modal sensory systems (vision and other balance systems) contributed to the postural regulation. The results are interpreted in terms of an ecological approach to posture in which postural regulation can be considered as an emergent phenomenon.     

身体锻炼对改善高血压状态的实验研究

将29名高血压病患随机分成对照组、药物组和实验组三个组别,进行为期6个月的观察研究。研究发现连续2个月以上的中等强度的运动可造成动脉血压缓慢下降,三个月后出现显性下降,其SBP和DBP分别从实验前的159±16和95±9mmHg下降到148±13和85±7mmHg．其降压效果与药物降压相比无明显差异。可见持之以恒的身体运动可作为高血压病的一种实用安全有效且不降低生活质量的疗法。     

Core stability training on lower limb balance strength

This study aimed to assess the effects of core stability training on lower limbs’ muscular asymmetries and imbalances in team sport. Twenty footballers were divided into two groups, either core stability or control group. Before each daily practice, core stability group (n = 10) performed a core stability training programme, while control group (n = 10) did a standard warm-up. The effects of the core stability training programme were assessed by performing isokinetic tests and single-leg countermovement jumps. Significant improvement was found for knee extensors peak torque at 3.14 rad · s^?1 (14%; P < 0.05), knee flexors peak torque at 1.05 and 3.14 rad · s^?1 (19% and 22% with P < 0.01 and P < 0.01, respectively) and peak torque flexors/extensors ratios at 1.05 and 3.14 rad · s^?1 (7.7% and 8.5% with P < 0.05 and P < 0.05, respectively) only in the core stability group. The jump tests showed a significant reduction in the strength asymmetries in core stability group (?71.4%; P = 0.02) while a concurrent increase was seen in the control group (33.3%; P < 0.05). This study provides practical evidence in combining core exercises for optimal lower limbs strength balance development in young soccer players.     

康复运动处方对青少年支气管哮喘患者呼吸机能的影响

观察康复运动处方对青少年支气管哮喘患者呼吸机能的影响。支气管哮喘患者31例，随机分成A、B两组，A组11例维持已有的药物治疗；B组20例在已有药物治疗基础上实施康复运动处方。两组的观察时间均为12周，对所有患者试验前后的哮喘症状、肺功能及不良反应进行了随访观察和测定。结果：肺活量、肺功能FEV1、PEF明显改善，提示哮喘症状呈逐步稳定状态。喘息、痰量、哮呜音症状改善有效率分别为A组63．64％、45．45％、54．56％；B组85％、75％、80％。试验所取得的正向效果。证明了康复运动处方对改善和提高青少年支气管哮喘患者的呼吸机能有显著效果．     

Dual-task effect on postural control in high-level competitive dancers

Abstract

We investigated balance in 33 competitive dancers (17 females, 16 males) and 22 controls (17 females, 5 males) (age 16–27 years) on a force plate in two conditions: single task (quiet stance) and dual task (with a concurrent mental task). Balance was evaluated using centre-of-pressure shift (sway) variability, mean speed, frequency, and sample entropy. The effect of the dual task in the medio-lateral plane was comparable in both groups, decreasing sway variability (P < 0.05) and increasing mean speed (P < 0.001), frequency, and sample entropy (P < 0.001), showing that the participants effectively increased the level of automaticity. In the antero-posterior plane, the dual task also increased sway frequency and sample entropy (P < 0.01) in dancers without affecting their standing performance. In contrast, postural control in non-dancers was vulnerable to reduced cognitive investment, which adversely interfered with baseline performance. There were very high correlations between sway sample entropy and frequency in each group, plane, and task (r = 0.92–0.98, P < 0.001), indicating that both parameters may measure the same characteristic of postural control and that higher sway frequency may play an important role in protecting stability in dual tasking. The postural control of dancers and non-dancers appears to be similar, although dancing seems to facilitate the increased level of automatic control in the antero-posterior plane.     

The effect of short-term isometric training on core/torso stiffness

“Core” exercise is a basic part of many physical training regimens with goals ranging from rehabilitation of spine and knee injuries to improving athletic performance. Core stiffness has been proposed to perform several functions including reducing pain by minimising joint micro-movements, and enhancing strength and speed performance. This study probes the links between a training approach and immediate but temporary changes in stiffness. Passive and active stiffness was measured on 24 participants; 12 having little to no experience in core training (inexperienced), and the other 12 being athletes experienced to core training methods; before and after a 15 min bout of isometric core exercises. Passive stiffness was assessed on a “frictionless” bending apparatus and active stiffness assessed via a quick release mechanism. Short-term isometric core training increased passive and active stiffness in most directions for both inexperienced and experienced participants, passive left lateral bend among experienced participants being the exception (P < 0.05). There was no difference between the inexperienced and experienced groups. The results confirm that the specific isometric training exercise approach tested here can induce immediate changes in core stiffness, in this case following a single session. This may influence performance and injury resilience for a brief period.     

The effect of core training on distal limb performance during ballistic strike manoeuvres

Ballistic limb motion is enabled by proximal “core” stiffness. However, controversy exists regarding the best method of training this characteristic. This study sought to determine the most effective core training method to enhance distal limb athleticism. A total of 12 participants (24 ± 3 years, 1.8 ± 0.05 m, 76.8 ± 9.7 kg) consisting of Muay Thai athletes performed a core training protocol (Isometric vs. Dynamic, with Control) for 6 weeks, using a repeated measures design to assess performance (peak strike velocity, peak impact force, muscular activation) in various strikes. Isometric training increased impact force in Jab (554.4 ± 70.1 N), Cross (1895.2 ± 203.1 N), Combo (616.8 ± 54.9 N), and Knee (1240.0 ± 89.1 N) trials (P < 0.05). Dynamic training increased strike velocity in Jab (1.3 ± 0.2 m · s^?1), Cross (5.5 ± 0.9 m · s^?1), Combo (0.7 ± 0.1, 2.8 ± 0.3 m · s^?1), and Knee (3.2 ± 0.3 m · s^?1) trials (P < 0.05). Isometric training increased Combo impact force 935.1 ± 100.3 N greater than Dynamic and 931.6 ± 108.5 N more than Control (P < 0.05). Dynamic training increased Jab strike velocity 1.3 ± 0.1 m · s^?1 greater than Isometric and 0.8 ± 0.1 m · s^?1 more than Control (P < 0.05). It appears that both static and dynamic approaches to core training are needed to enhance both velocity and force in distal limbs.     

The effects of plyometric exercise on unilateral balance performance

Abstract

The purpose of this study was to determine the effects of plyometric exercise on unilateral balance performance. Nine healthy adults performed baseline measurements on the dominant limb that consisted of: a 20-s unilateral stability test on a tilt balance board, where a higher stability index represented deterioration in balance performance; isokinetic plantar flexion torque at 0.52 and 3.14 rad · s^?1; muscle soreness in the calf region; and resting plantar flexion angle. Plyometric exercise consisted of 200 counter-movement jumps designed to elicit symptoms of muscle damage, after which baseline measurements were repeated at 30 min, 24, 48, and 72 h. Perceived muscle soreness of the calf region increased significantly following the plyometric exercise protocol (F_4,32 = 17.24, P < 0.01). Peak torque was significantly reduced after the plyometric exercise protocol (F_4,32 = 7.49, P < 0.05), with greater loss of force at the lower angular velocity (F_4,32 = 3.46, P < 0.05), while resting plantar flexion angle was not significantly altered compared with baseline values (P > 0.05). The stability index was significantly increased (F_4,32 = 3.10, P < 0.05) above baseline (mean 2.3, s = 0.3) at 24 h (3.3, s = 0.4), after which values recovered. These results indicate that there is a latent impairment of balance performance following a bout of plyometric exercise, which has implications for both the use of skill-based activities and for increased injury risk following high-intensity plyometric training.     

The effects of plyometric exercise on unilateral balance performance

The purpose of this study was to determine the effects of plyometric exercise on unilateral balance performance. Nine healthy adults performed baseline measurements on the dominant limb that consisted of: a 20-s unilateral stability test on a tilt balance board, where a higher stability index represented deterioration in balance performance; isokinetic plantar flexion torque at 0.52 and 3.14 rad s(-1); muscle soreness in the calf region; and resting plantar flexion angle. Plyometric exercise consisted of 200 counter-movement jumps designed to elicit symptoms of muscle damage, after which baseline measurements were repeated at 30 min, 24, 48, and 72 h. Perceived muscle soreness of the calf region increased significantly following the plyometric exercise protocol (F(4,32) = 17.24, P < 0.01). Peak torque was significantly reduced after the plyometric exercise protocol (F(4,32) = 7.49, P < 0.05), with greater loss of force at the lower angular velocity (F(4,32) = 3.46, P < 0.05), while resting plantar flexion angle was not significantly altered compared with baseline values (P > 0.05). The stability index was significantly increased (F(4,32) = 3.10, P < 0.05) above baseline (mean 2.3, s = 0.3) at 24 h (3.3, s = 0.4), after which values recovered. These results indicate that there is a latent impairment of balance performance following a bout of plyometric exercise, which has implications for both the use of skill-based activities and for increased injury risk following high-intensity plyometric training.     

动态平衡训练对膝关节位置觉干预效果的研究

目的:研究动态平衡训练对膝关节位置觉的干预效果及其预防损伤机制,比较平衡板、平衡气囊、瑞士球训练方法改善下肢本体感觉功能的效果,为预防运动损伤提供理论依据和实践指导.方法:41名受试者分成平衡板平衡气囊训练组(n=13),瑞士球训练组(n=14),对照组(n=14),训练时间共8周,每周3次,每次练习50分钟,8周训练前后测试膝关节主动和被动位置觉.结果:①8周平衡板气囊训练和瑞士球训练后,男女受试者右膝关节位置觉(主动和被动)比训练前减小但无显著性差异(P＞0.05);②平衡板气囊组与瑞士球组在改善膝关节位置觉无显著差异(P ＞0.05).结论:8周动态平衡训练时间较短不足以使膝关节位置觉显著改变,但训练后位置觉平均误差减小,表明平衡板气囊训练和瑞士球训练对改善膝关节位置觉感知能力有积极意义.     

Effects of balance training on postural sway, leg extensor strength, and jumping height in adolescents

Deficits in strength of the lower extremities and postural control have been associated with a high risk of sustaining sport-related injuries. Such injuries often occur during physical education (PE) classes and mostly affect the lower extremities. Thus, the objectives of this study were to investigate the effects of balance training on postural sway, leg extensor strength, and jumping height in adolescents. Twenty high school students participated in this study and were assigned to either an intervention (n = 10) or control group (n = 10). The intervention group participated in a 4-week balance-training program integrated in their physical education lessons. Pre- and posttests included the measurements of postural sway on a balance platform, jumping height on a force platform, and maximal isometric leg extension force on a leg-press. Balance training resulted in significantly improved postural control, increased jumping height, and enhanced rate of force development of the leg extensors. Physiological adaptations rather than learning effects seem to be responsible for the observed findings. These results could have an impact on improving the performance level in various sports and on reducing the injury prevalence of the lower extremities.     

Effect of Kinesio Taping and balance exercises on postural control in amateur soccer players: A randomised control trial

ABSTRACT

The objective of this study was to determine the effect of Kinesio Taping (KT), alone or together with balance exercises (BE), on parameters related to postural control, such as dynamic balance, static balance and flexibility. Forty-four male amateur soccer players (mean age 24.45 (4.79) years) were randomly allocated to 3 groups: KT+BE that received KT and BE (n = 16); KT_p+BE, in which the KT was used as a placebo (n = 15) and KT alone (n = 13). The intervention period lasted 4 weeks. Star Excursion Balance Test (SEBT), Unipedal Stance Test (UST) and the Toe Touch Test (TTT) were assessed at baseline (pre), two weeks after beginning the treatment (mid) and after the intervention (post). We observed a significant improvement on the SEBT (mid and post-treatment) and the UST (post-treatment), but not on the TTT in either KT+BE or KT_p+BE groups post treatment. No differences were found either in KT group at any time point or between groups in any variable studied. In conclusion, KT functional correction technique does not improve static and dynamic balance when applied alone, whereas BE alone or combined with KT significantly improves these variables. None of these techniques has any effect on flexibility.

Abbreviation: KT: Kinesiotaping; BE: Balance exercises; KTp: Placebo Kinesiotaping; UST: Unipedal Stance Test; SEBT: Star Excursion Balance Test; TTT: Toe Touch Test     

复能饮料对游泳运动员运动能力的影响

将16名游泳运动员随机分为对照组(n=8)、实验组(n=8),进行为期4周的大强度训练。实验前、训练两周后及实验后对受试对象的血液生化指标进行测试。结果:实验组与对照组比较,血清睾酮水平显著升高(P<0.05),血清肌酸激酶显著下降(P<0.05),血色素相对稳定。提示复能饮料有提高运动能力、促进骨骼肌损伤组织修复以及减少细胞内肌酸激酶外渗的作用。     

不同负荷的运动训练对大鼠心血管系统调节肽分泌的影响

为了研究不同负荷的运动训练对机体心血管系统神经调节肽分泌的影响 ,本文通过对大鼠进行为期 8周的不同负荷的游泳训练 ,并测定血浆神经肽Y(NPY)和降钙素基因相关肽 (CGRP)的含量。结果发现 :① 1h的运动训练可使血浆NPY含量显著下降 ,NPY/CGRP有下降趋势。降低机体交感神经的兴奋性 ,抑制NPY的分泌。② 2h训练组血浆NPY含量显著高于对照组和 1h训练组 ,血浆CGRP含量显著低于对照组 ,NPY/CGRP显著高于对照组和 1h训练组。动态观察血浆NPY和CGRP的含量对于在运动过程中对心血管系统进行医务监督、预防过度训练的发生具有一定的指导意义     

水中康复操对运动员关节损伤后肢体功能恢复的影响研究

目的：观察水中康复操对运动员关节损伤后肢体功能恢复的效果。方法：将80例在运动中关节损伤的患者随机分为试验组和对照组各40例,两组患者均进行相同的康复操锻炼,试验组在音乐的伴奏下,在深度为1.1-1.5米的水中进行操化锻炼。结果：试验组与对照组的效果对比,试验组总有效率为95%,明显优于对照组80%（P（0.01）。结果：水中康复操的锻炼对运动员关节损伤后肢体功能的恢复有很好的效果。     

竞技体育专项训练特征及其运动训练学分析

从运动训练学角度,对专项训练多周期年度训练计划特征、专项训练的运动生理学特征、专项训练方法评价的特征进行阐释,旨在为提高运动员的专项成绩提供参考。     

The effects of chronic exercise training status on motor unit activation and deactivation control strategies

This study examined the mechanomyographic (MMG_RMS) amplitude–force relationships for 5 (age = 19.20 ± 0.45 years) aerobically trained (AT), 5 (age = 25 ± 4.53 years) resistance-trained (RT) and 5 (age = 21.20 ± 2.17 years) sedentary (SED) individuals. Participants performed an isometric trapezoidal muscle action at 60% maximal voluntary contraction of the leg extensors that included linearly increasing, steady force, and linearly decreasing muscle actions. MMG and skinfold thickness were recorded from the vastus lateralis. b and a terms were calculated from the natural log-transformed MMG_RMS–force relationships (linearly increasing and decreasing segments) for each participant. An average of MMG_RMS was calculated for the entire steady force segment. The b terms for the RT (0.727 ± 0.334) and SED (0.622 ± 0.281) were significantly greater (P < 0.05) than the AT (0.159 ± 0.223) and were greater during the linearly increasing (0.622 ± 0.426) than decreasing (0.383 ± 0.269) segments when collapsed across segments and training status, respectively. MMG_RMS during the steady force segment and skinfold thicknesses were not different among training statuses (P = 0.106, P = 0.142). Motor unit (MU) activation strategies were influenced as a function of exercise training status and muscle action. Future research is needed to fully understand the implications of these changes in MU control strategies as a result of chronic exercise training on exercise and athletic performance.     

长期有规律的体育运动对老年人I型和Ⅱ型T细胞因子平衡的影响

为了检验长期习惯性的体育运动是否影响老年人I型和Ⅱ型T细胞因子的平衡。通过对9名老年妇女(平均年龄(63±1)岁,最大耗氧量(32.2±1.0)mL.kg-1.min-1)进行步行训练;挑选12名不进行运动训练的老年(妇女平均年龄(63±1)岁,最大耗氧量(27.8±0.9)mL.kg-1.min-1)和9名不进行运动训练的年轻妇女(平均年龄(26±1)岁,最大耗氧量(37.8±1.3)mL.kg-1.min-1);然后检测了CD4 和CD8 T细胞中IFN-γ、IL-2和IL-4的水平,并对I型和Ⅱ型T细胞进行了比较。结果:老年人运动组表达IFN-γ的CD4 细胞数目与比青年非运动组比较,差异有显著性(P<0.01);老年运动组表达IL-2的CD8 的T细胞数目与老年非运动组比较差异有显著性(P<0.05);青年组表达IL-4的CD8 细胞与老年非运动组比较,差异有显著性(P<0.01);3组中CD4 和CD8 T细胞中IFN-γ/IL-4的比率差异无显著性。实验结果显示年龄对I型和Ⅱ型T细胞的影响比运动训练对它的影响更大。