男子下蹲式抓举技术动作的生物力学特征分析

目的研究不同抓举重量下男子抓举技术动作的生物力学特征。方法利用8通道EMG测量系统、三维测力平衡系统和数码摄像机,对上海市举重队现役男子举重运动员在不同重量下抓举过程中的8块具有代表性的浅层骨骼肌的表面肌电、足底反力和抓举视频做同步采集。结果不同抓举重量下举重运动员的足底反力变化曲线趋势一致,基于足底反力曲线中的特征点对抓举技术动作阶段可划分为7个阶段,预备阶段、伸膝提铃阶段、引膝提铃阶段、发力阶段、惯性上升阶段、下降定铃阶段和起立阶段。抓举过程中肌群活动的时间顺序为:背阔肌、竖脊肌、肌直肌、三角肌、肱三头肌、胫骨前肌、肱二头肌和斜方肌。其中,斜方肌的积分肌电值最大,背阔肌的积分肌电值最小。随着抓举重量的增加,肱三头肌和三角肌的积分肌电值增加最大。结论为提高举重运动员抓举项目的比赛成绩,运动员应该重视斜方肌、肱三头肌和三角肌的训练。     

膝骨关节炎患者膝关节置换后下肢肌的表面肌电图变化

背景：膝骨关节炎患者膝关节置换后下肢肌功能恢复一直存在着争议。 目的：评价膝骨关节炎患者膝关节置换手术后下肢肌肉功能。 方法：应用TELEMYO 2400R G2表面肌电图遥测仪对25例双膝骨关节炎单膝关节置换后患者在平常自然步态下进行双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧的表面肌电信号测试。在肌电图测试前,对患者双膝关节功能进行美国特种外科医院膝关节评分。 结果与结论：患者置换后美国特种外科医院膝关节评置换侧平均分91.44,其优良率达100%;未置换侧平均分54.52。置换侧在疼痛、关节功能方面有明显改善;膝关节置换后置换侧股直肌、胫前肌、股二头肌的肌电振幅、肌电积分、平均频率、中位频率的(平均值、最小值、最大值)与未置换侧相比差异无显著性意义(P > 0.05);置换侧腓肠肌内侧肌电振幅值及肌电积分值显著大于未置换侧(P < 0.05);置换侧腓肠肌内侧平均频率、中位频率与未置换侧相比差异无显著性意义(P > 0.05)。提示膝关节置换后置换侧的下肢肌没有恢复到正常的功能活动水平,因此膝关节置换后康复要特别重视患者的肌肉锻炼。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

传统武术站桩肩背部负载分配的力学效果评价

目的 研究长期进行传统武术站桩训练者站桩时不同肌肉负载的分配情况,评价站桩效果。方法 采用加拿大Flexcomp Infiniti10通道表面肌电采集系统,测量受试者（桩法训练组和对照组各7名）在站桩过程中肱桡肌、肱三头肌、三角肌、背阔肌和小腿三头肌的表面肌电,观察不同肌肉肌电在不同负载下的变化趋势,对其积分肌电（integral electromyography,IEMG）进行对比分析。结果 随着负载的增加,训练组背部和肩部IEMG的比值稳定在(0.372±0.258)与(0.257±0.146)之间,而对照组则在(1.313±0.698)与(0.800±0.405)之间。结论 训练组在空手站桩和负重站桩时,主要压力会集中在背阔肌,而对照组则集中在三角肌。     

颈肩痛患者颈肩部肌肉的表面肌电图特征

背景：颈肩痛是由颈肩部软组织(主要是肌肉)的慢性劳损所引起的常见临床症状。表面肌电图是一种新型、无创的肌肉活动检查手段,能测量肌肉的活动和功能。 目的：评价颈肩疼痛患者颈肩部肌肉功能,为表面肌电图的应用和颈肩疼痛患者合理防治与康复提供理论依据。 方法：应用表面肌电图对32例单侧颈肩疼痛的办公室工作人员在站立下,进行低头、头后伸、双手上举时颈竖脊肌、斜方肌上支的表面肌电测试。在测试前,对患者的颈肩疼痛进行目测类比评分。然后根据收集的数据,比较受试者颈肩部疼痛侧与非疼痛侧测试肌肉的肌电活动。 结果与结论：测试前,受试者颈肩疼痛目测类比评分(平均分)为5.03分;受试者在低头、头后伸、双手上举过程中,其疼痛侧的颈竖脊肌、斜方肌上支的肌电原始信号较非疼痛侧的颈竖脊肌、斜方肌上支的肌电原始信号弱;疼痛侧颈竖脊肌、斜方肌上支肌电的平均振幅值与非疼痛侧相比差异有显著性意义(P < 0.05);疼痛侧颈竖脊肌、斜方肌上支肌电的平均频率斜率值与非疼痛侧相比差异无显著性意义(P > 0.05)。提示颈肩疼痛患者疼痛侧的颈肩肌肉的活动能力下降,长期坐位作业的办公室人员要定时进行颈肩部肌肉锻炼。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

正常青年人自然步态下肢肌的表面肌电图分析◆

背景：肌肉的生物电活动是人体的能动部分,可反映人体运动的功能。 目的：观察和分析正常青年人在自然步态中下肢肌肉的表面肌电活动。 方法：采用美国NORAXON公司生产的 TELEMYO 2400R G2表面肌电图仪对30例正常青年人在平地自然行走时,其双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧进行测试,分析在正常步态中受试肌群表面肌电信号的变化规律。 结果与结论：正常青年人平地自然步行中,其双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧的肌电随步态周期呈活动与静止周期性变化,左右侧同名肌肉交替活动;平均肌电振幅、平均肌电积分、平均频率、中位频率值最大的是腓肠肌内侧,其余由大到小依次是胫前肌,股二头肌,股直肌,右左腿分布规律一致;右侧腓肠肌内侧平均肌电振幅、平均频率、中位频率值均明显低于左侧(P < 0.05);受试肌的时域、频域值波动在一定范围。提示正常青年人自然步态中下肢肌群肌电活动呈节律性和右左侧交替活动;在受试肌中腓肠肌内侧的肌电活动最强;腓肠肌内侧的肌电活动存在着优势侧与非优势侧的轻度差别;下肢肌肌电活动的时域、频域值在一定范围波动。      

表面肌电信号评价呼吸电刺激治疗功能性便秘的疗效

目的　利用表面肌电测量腹肌、膈肌和盆底肌肌电改变,评价呼吸电刺激治疗功能性便秘的疗效。 方法　共31例功能性便秘患者纳入研究,按随机数字表法分为对照组和治疗组,对照组采用单纯盆底生物反馈治疗（16例）,治疗组在盆底生物反馈治疗基础上进行呼吸电刺激训练（15例）。分别于治疗前以及治疗后对两组选用便秘评分系统进行评估,采用表面肌电图技术检测膈肌和下腹肌表面肌电均方根,Glazer法评估盆底肌肌电参数。 结果　治疗2周后,两组患者便秘评分系统评估较治疗前下降（P<0.05）,且治疗组评分低于对照组（P<0.05）;两组患者的膈肌和腹直肌均方根值较治疗前改善（P<0.05）,且治疗组膈肌肌电均方根值改善程度与对照组比较有统计学差异（P<0.05）。治疗后,Glazer法评估两组患者前基线、后基线波幅值较治疗前降低（P＜0.05）,且治疗组前基线波幅值较对照组降低,差异有统计学意义（P<0.05）。 结论　呼吸电刺激训练可有效提高膈肌、腹肌收缩力,降低盆底肌的过度活动,增强盆底生物反馈治疗改善功能性便秘的治疗效果。     

俯卧撑中前臂旋转对上肢肌肉电活动的影响

目的 分析俯卧撑中前臂旋转对上肢肌肉电活动的影响。方法 采集十个对象在前臂内旋90°（IR90）,中立位（NEU）和外旋90°（ER90）三个支撑位下肱三头肌长头和侧头、三角肌前部和中部、胸大肌和肱二头肌的肌电信号,计算肌电信号的均方根值,并作归一化处理,运用单因素方差分析法比较不同支撑位下肌电信号的差异。同时对一个周期内肌电信号进行包络线分析。结果 从IR90到ER90,肱三头肌长头信号无显著变化,肱三头肌侧头和三角肌中部信号逐渐减小,而三角肌前部、胸大肌和肱二头肌则逐渐增大。另外,包络分析结果显示了三种不同类型的肌电信号曲线。结论 不同前臂转动支撑位对肌肉活性产生影响,而对各肌肉的影响程度和方式并不相同。     

家兔腓肠肌在电刺激下力学行为的实验研究

目的 获得肌肉收缩力学特性与其电生理特性间的实验关系。方法 用肌电仪发出不同波宽、不同强度的脉冲电流，对家兔的胫神经进行刺激，记录其复合动作电位及收缩力。结果 得到了收缩力与各种肌电信号的实验关系曲线。结论收缩力与刺激电流之间呈正相关关系、与复合动作电位幅值(CAMP)之间呈线性关系，且收缩力与肌电积分值之间也呈较好的线性关系。     

痉挛型脑瘫儿童手术后表面肌电信号和关节角度评估

目的 通过表面肌电(surface electromyography, sEMG)和关节角度评估脑瘫儿童手术后运动功能。方法 采集16名痉挛型脑瘫患儿手术前后直线行走时股直肌、股二头肌、半腱肌、胫骨前肌、腓肠肌内外侧sEMG和髋、膝、踝关节角度,计算各步态时期sEMG均方根、积分肌电值和关节角度均值,进行肌力肌张力评估。结果 手术后,患儿下肢肌肉肌张力均显著降低(P<0.05),股直肌和股二头肌在摆动阶段肌力减小。胫骨前肌在摆动中末期肌力增大(P<0.05)。髋、膝关节屈曲角降低(P<0.05)。踝关节背屈角增大(P<0.05),内翻角减小(P<0.05)。结论 治疗后患者蹲伏步态和马蹄内翻足均得到改善,运动功能得到提升。sEMG结合关节角度分析可对患者肌肉功能进行定量评估,为临床诊断提供参考。     

穿戴塑料踝足矫形器对下肢肌肉疲劳性的影响

背景：目前尚未见到系统研究踝足矫形器对下肢肌肉影响的文献。 目的：提取正常人穿戴固定踝足矫形器时的下肢肌电信号,分析固定踝足矫形器对下肢肌肉疲劳性的影响。 方法：选择5名健康男性受试者参加试验,每名受试者分别进行3组试验：①第1组,在不穿戴任何矫形器的情况下以自然步态行走。②第2组,受试者穿戴平跟踝足矫形器以自然步态行走(此时矫形器踝部包裹超过踝中心1 cm,记1.0 cm),穿戴同一矫形器但在踝部去掉1.0 cm、踝部塑料边缘刚好通过踝中心时采集(记     0 cm),在踝部再去掉1.0 cm后以自然步态行走(记-1.0 cm)。③第3组,受试者穿戴1.5 cm正常跟高踝足矫形器以自然步态行走,穿戴同一矫形器,但跟高分别改为1.0,2.0 cm后以自然步态行走。行走中采用肌电采集仪检测受试者下肢股二头肌、股直肌、胫骨前肌、腓肠肌的表面肌电信号。 结果与结论：①正常不穿戴任何矫形器时,4块肌肉的肌电信号是最弱的。②对于任何一块肌肉,正常不穿戴矫形器时所对应肌电值比穿戴不同硬度矫形器时所对应的肌电值要小。③对于股二头肌,正常不穿戴矫形器时所对应的积分肌电值与穿戴正常跟高矫形器时所对应的值很接近,同时这两个值要比穿戴不正常跟高矫形器时所对应的积分肌电值小。表明固定塑料踝足矫形器会引起股二头肌、股直肌、胫骨前肌、腓肠肌的疲劳,当固定塑料踝足矫形器的跟高不合适时会进一步增加股二头肌的疲劳程度。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

The moment arms of the muscles spanning the glenohumeral joint: a systematic review

The moment arm of a muscle represents its leverage or torque‐producing capacity, and is indicative of the role of the muscle in joint actuation. The objective of this study was to undertake a systematic review of the moment arms of the major muscles spanning the glenohumeral joint during abduction, flexion and axial rotation. Moment arm data for the deltoid, pectoralis major, latissimus dorsi, teres major, supraspinatus, infraspinatus, subscapularis and teres minor were reported when measured using the geometric and tendon excursion methods. The anterior and middle sub‐regions of the deltoid had the largest humeral elevator moment arm values of all muscles during coronal‐ and scapular‐plane abduction, as well as during flexion. The pectoralis major, latissimus dorsi and teres major had the largest depressor moment arms, with each of these muscles exhibiting prominent leverage in shoulder adduction, and the latissimus dorsi and teres major also in extension. The rotator cuff muscles had the largest axial rotation moment arms regardless of the axial position of the humerus. The supraspinatus had the most prominent elevator moment arms during early abduction in both the coronal and scapular planes as well as in flexion. This systematic review shows that the rotator cuff muscles function as humeral rotators and weak humeral depressors or elevators, while the three sub‐regions of the deltoid behave as substantial humeral elevators throughout the range of humeral motion. The pectoralis major, latissimus dorsi and teres major are significant shoulder depressors, particularly during abduction. This study provides muscle moment arm data on functionally relevant shoulder movements that are involved in tasks of daily living, including lifting and pushing. The results may be useful in quantifying shoulder muscle function during specific planes of movement, in designing and validating computational models of the shoulder, and in planning surgical procedures such as tendon transfer surgery.     

Musculotopic organization of the motor neurons supplying forelimb and shoulder girdle muscles in the mouse

We identified the motor neurons (MNs) supplying the shoulder girdle and forelimb muscles in the C57BL/6J mouse spinal cord using Fluoro-Gold retrograde tracer injections. In spinal cord transverse sections from C2 to T2, we observed two MN columns (medial and lateral) both with ventral and dorsal subdivisions. The dorsolateral column consisted of the biceps brachii, forearm extensors, forearm flexors, and hand MNs, and the ventrolateral column consisted of the latissimus dorsi, trapezius, teres major, deltoid, and triceps MNs. The supraspinatus muscle MNs were located in the dorsomedial column, and pectoralis major and serratus anterior MNs were located in the ventromedial columns. MNs of the dorsolateral column innervated the biceps brachii in mid-C4 to mid-C7, forearm extensors in caudal C4 to mid-T1, forearm flexors in rostral C5 to mid-T1, and hand muscles in mid-C8 to mid-T2 segments. The MNs innervating the trapezius were located in mid-C2 to mid-C4, triceps brachii in mid-C6 to rostral T1, deltoid in rostral C4 to mid-C6, teres major in rostral C5 to mid-C8, and latissimus dorsi in mid-C5 to caudal C8. In addition, MNs innervating the supraspinatus were located from rostral C4 to caudal C8, pectoralis major in mid-C6 to mid-T2, and serratus anterior in rostral C5 to caudal C7/rostral C8 segments. While the musculotopic pattern of MN groups was very similar to that documented for other species, we found differences in the position and cranio-caudal extent of some MN pools compared with previous reports. The identification of mouse forelimb MNs can serve as an anatomical reference for studying degenerative MN diseases, spinal cord injury, and developmental gene expression.     

Motor point map of upper body muscles

Purpose

The purpose of the present study was to systematically investigate the upper body motor point (MP) positions of selected muscles and to create an atlas of the identified MPs.

Methods

MPs were searched bilaterally in 15 male and 15 female subjects by scanning the skin with a special pen electrode at low stimulation frequency (3 Hz) and current amplitude (<10 mA). The following muscles were investigated: biceps brachii, triceps brachii, deltoideus, trapezius, latissimus dorsi, erector spinae (lumbar part), pectoralis minor and major, and rectus abdominis.

Results

A total of 1,563 MPs were identified. The MPs could be clustered into 31 distinct positions on each side of the body. However, the number of MPs per muscle varied between subjects: 2 MPs were found for the biceps brachii, 2–3 for the triceps brachii, 4–5 for the deltoideus, 2–3 for the pectoralis major, 1 MP for the pectoralis minor, 4–5 for the trapezius, 3–4 for the latissimus dorsi, 4–5 for the rectus abdominis, and 2–3 for the erector spinae in its lumbar part. Referring to the applied grid, upper limb and lower back muscles presented a low inter-individual variation, whereas MPs of the deltoideus, the pectoralis major, and the rectus abdominis were characterized by a poor homogeneity. All MPs were found to be highly symmetrical between both sides of the body (r = 0.96; p < 0.001).

Conclusion

The presented data and the corresponding map will help physiotherapists, and conditioning specialists improve their neuromuscular electrical stimulation therapy or training, respectively.     

Assessment of the maximum voluntary arm muscle contraction in sign language for the deaf

OBJECTIVE: The purpose of this study was to investigate the levels of upper member muscles' activation of deaf individuals, who use the Brazilian sign language - LIBRAS, comparing these findings to volunteers with no postural deviations and normal hearing METHODS: Forty eight volunteers divided into two groups comprising healthy and deaf subjects (24 volunteers for each group). The signs of rest were obtained with the volunteer maintaining the upper member in an anatomical position, but with the forearm flexed and sustained by the lower member. Maximum voluntary isometric contractions (MVIC) of the biceps, triceps, deltoid, and trapezius muscles were performed in the position of muscular function testing. Statistical analysis was performed using the SPSS-10.0. Continuous data with normal distribution were analyzed by ANOVA with the significance level of p < 0.01. RESULTS: The normalized electromyographic muscle data obtained in muscular rest do not show statistically significant differences among the studies muscles, in both groups. In the comparison of normalized RMS values obtained in MVIC, the mean values for the trapezius muscle of deaf group were statistically lower than control group. CONCLUSIONS: This study's results indicate there are no differences between the levels of muscular activation for arm biceps, arm triceps, and the anterior portion of the deltoid muscle between the mean normalized RMS values of deaf and healthy individuals.     

Moment arms of the muscles crossing the anatomical shoulder

The objective of the present study was to determine the instantaneous moment arms of 18 major muscle sub-regions crossing the glenohumeral joint during coronal-plane abduction and sagittal-plane flexion. Muscle moment-arm data for sub-regions of the shoulder musculature during humeral elevation are currently not available. The tendon-excursion method was used to measure instantaneous muscle moment arms in eight entire upper-extremity cadaver specimens. Significant differences in moment arms were reported across sub-regions of the deltoid, pectoralis major, latissimus dorsi, subscapularis, infraspinatus and supraspinatus (P < 0.01). The most effective abductors were the middle and anterior deltoid, whereas the most effective adductors were the teres major, middle and inferior latissimus dorsi (lumbar vertebrae and iliac crest fibers, respectively), and middle and inferior pectoralis major (sternal and lower-costal fibers, respectively). In flexion, the superior pectoralis major (clavicular fibers), anterior and posterior supraspinatus, and anterior deltoid were the most effective flexors, whereas the teres major and posterior deltoid had the largest extensor moment arms. Division of multi-pennate shoulder muscles of broad origins into sub-regions highlighted distinct functional differences across those sub-regions. Most significantly, we found that the superior sub-region of the pectoralis major had the capacity to exert substantial torque in flexion, whereas the middle and inferior sub-regions tended to behave as a stabilizer and extensor, respectively. Knowledge of moment arm differences between muscle sub-regions may assist in identifying the functional effects of muscle sub-region tears, assist surgeons in planning tendon reconstructive surgery, and aid in the development and validation of biomechanical computer models used in implant design.     

The influence of experimentally induced pain on shoulder muscle activity

Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven healthy men (range 22–27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0°–105°) at a speed of approximately 120°/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows that acute pain both subacromially and in the supraspinatus muscle modulates coordination of the shoulder muscles during voluntary movements. During painful conditions, an increased activity was detected in the antagonist (latissimus), which support the idea that localized pain affects muscle activation in a way that protects the painful structure. Further, the changes in muscle activity following subacromial pain induction tend to expand the subacromial space and thereby decrease the load on the painful structures.     

Lines of action and stabilizing potential of the shoulder musculature

The objective of the present study was to measure the lines of action of 18 major muscles and muscle sub‐regions crossing the glenohumeral joint of the human shoulder, and to compute the potential contribution of these muscles to joint shear and compression during scapular‐plane abduction and sagittal‐plane flexion. The stabilizing potential of a muscle was found by assessing its contribution to superior/inferior and anterior/posterior joint shear in the scapular and transverse planes, respectively. A muscle with stabilizing potential was oriented to apply more compression than shear at the glenohumeral joint, whereas a muscle with destabilizing potential was oriented to apply more shear. Significant differences in lines of action and stabilizing capacities were measured across sub‐regions of the deltoid and rotator cuff in both planes of elevation (P < 0.05), and substantial differences were observed in the pectoralis major and latissimus dorsi. The results showed that, during abduction and flexion, the rotator cuff muscle sub‐regions were more favourably aligned to stabilize the glenohumeral joint in the transverse plane than in the scapular plane and that, overall, the anterior supraspinatus was most favourably oriented to apply glenohumeral joint compression. The superior pectoralis major and inferior latissimus dorsi were the chief potential scapular‐plane destabilizers, demonstrating the most significant capacity to impart superior and inferior shear to the glenohumeral joint, respectively. The middle and anterior deltoid were also significant potential contributors to superior shear, opposing the combined destabilizing inferior shear potential of the latissimus dorsi and inferior subscapularis. As potential stabilizers, the posterior deltoid and subscapularis had posteriorly‐directed muscle lines of action, whereas the teres minor and infraspinatus had anteriorly‐directed lines of action. Knowledge of the lines of action and stabilizing potential of individual sub‐regions of the shoulder musculature may assist clinicians in identifying muscle‐related joint instabilities, assist surgeons in planning tendon reconstructive surgery, aid in the development of rehabilitation procedures designed to improve joint stability, and facilitate development and validation of biomechanical computer models of the shoulder complex.     

Effect of arm-shoulder fatigue on carpenters at work

Summary The purpose of the study was to analyse the effect of arm-shoulder fatigue on manual performance. Ten experienced carpenters performed three standardized tasks (nailing, sawing and screwing). Electromyographic activity was recorded from six arm-shoulder muscles and the performances were video-filmed. After 45 min of standardized arm-cranking (arm-shoulder-fatiguing exercise of approximately 70%–80% maximal oxygen consumption), the tasks were repeated. The number of work movements and the time taken for each task were recorded and the quality of the work performed was compared. After the fatiguing exercise, only nailing was perceived as being harder and more mistakes were made during nailing and sawing. Movement performance was not influenced during nailing but was slightly slower during sawing and faster during screwing. However, there were increased mean EMG amplitudes in the upper trapezius and biceps muscles during nailing, in the upper trapezius, anterior deltoid and infraspinatus muscles during sawing and in the anterior deltoid muscle during screwing. Of the muscles studied the upper trapezius and anterior deltoid muscles increased their activity most after the arm-shoulder-fatiguing exercise.     

Evaluation of muscle fatigue during 100-m front crawl

The aim of this study was to evaluate muscle fatigue in upper body muscles during 100-m all-out front crawl. Surface electromyogram (EMG) was collected from the pectoralis major, latissimus dorsi and triceps brachii muscles of 11 experienced swimmers. Blood lactate concentration level increased to 14.1?±?2.9?mmol?l^?1 5?min after the swim. The velocity, stroke length and stroke rate calculated based on video analysis decreased by 15.0, 5.8 and 7.4%, respectively, during the swim. EMG amplitude of the triceps and the lower part of the latissimus muscles increased, whilst the mean power frequency (MNF) of all muscles significantly decreased by 20?C25%. No significant differences in the relative MNF decrease were observed amongst the muscles; however, the differences in the rate of the MNF decrease between the lower part of the latissimus and the triceps brachii muscles were found (P?<?0.05). The time of rest between the muscle activation of the two consecutive arm strokes at the end of swimming was extended (P?<?0.05). It was concluded that 100-m all-out crawl induced significant fatigue with no evident differences amongst the analysed muscles.