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1.
Literature concerning the theoretical role of spinal reflex circuits and their sensorimotor signals in proprioceptive neuromuscular facilitation (PNF) muscle stretching techniques was examined. Reviewed data do not support the assertion commonly made in PNF literature that contraction of a stretched muscle prior to further stretch, or contraction of opposing muscles during muscle stretch, produces relaxation of the stretched muscle. Further, following contraction of a stretched muscle, inhibition of the stretch reflex response lasts only 1 s. Studies examined suggested that decreases in the response amplitude of the Hoffmann and muscle stretch reflexes following a contraction of a stretched muscle are not due to the activation of Golgi tendon organs, as commonly purported, but instead may be due to presynaptic inhibition of the muscle spindle sensory signal. The current view on the complex manner by which the spinal cord processes proprioceptive signals was discussed. The ability of acute PNF stretching procedures to often produce a joint range of motion greater than that observed with static stretching must be explained by mechanisms other than the spinal processing of proprioceptive information. Studies reviewed indicate that changes in the ability to tolerate stretch and/or the viscoelastic properties of the stretched muscle, induced by PNF procedures, are possible mechanisms. 相似文献
2.
Jason B. Winchester Arnold G. Nelson Joke Kokkonen 《Research quarterly for exercise and sport》2013,84(2):257-261
While it has been well established that an acute stretching program can inhibit maximal muscle performance, the amount of stretching needed to produce the deleterious response is unknown. Therefore this study examined the dose-response relationship between acute stretching and strength inhibition. Eighteen college students performed a one repetition maximum (1-RM) test of knee-flexion following 0, 1, 2, 3, 4, 5, or 6 30-s bouts of hamstring stretching held at the limit of toleration. All seven dose variations were done by each subject, with each variation done on a separate day. One week separated each test, and the order of the stretch variations was balanced across the seven testing days. Stretching significantly (p < .05) reduced 1-RM after one 30-s stretch (5.4%), and continued to decrease 1-RM up to and including six 30-s stretches (12.4%). A single 30-s stretch, if held at the limit of toleration, is sufficient to cause an inhibition in a person's 1-RM. Additional bouts of stretching will further decrease the 1-RM, suggesting that multiple mechanisms may be involved in stretch-induced strength inhibition. 相似文献
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基于运动人体科学与运动训练学的相关理论，采用文献分析法、参与观察法、专家访谈法、问卷调查法等研究方法，对竞技太极拳中32系列难度动作落地单脚支撑技术特征进行理论分析和规律探讨。旨在从整体上系统地理解竞技太极拳中32系列难度动作各阶段间的关系，进而准确把握此类动作训练方法设计的理论基础，从而设计科学合理的训练方法，以提高运动员32系列难度动作落地单脚支撑的稳定性。研究得出，可通过SWISS球上俯卧转体等训练提高核心肌群的协调控制能力，BOSU球上单双腿直立或半蹲等练习增强髋关节肌群的离心收缩能力和协调控制能力，仰卧屈膝足跟夹SWISS球、手法松解等方式增强膝关节不同肌群的等长收缩、向心收缩、神经协调控制能力；通过踝关节PNF拉伸、跖趾关节PNF拉伸等增强足底非固有肌离心收缩能力和柔韧性，提高足底固有肌的神经协调能力。 相似文献
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Acute effects of passive muscle stretching on sprint performance 总被引：1，自引：0，他引：1
Nelson AG Driscoll NM Landin DK Young MA Schexnayder IC 《Journal of sports sciences》2005,23(5):449-454
The results of previous research have shown that passive muscle stretching can diminish the peak force output of subsequent maximal isometric, concentric and stretch-shortening contractions. The aim of this study was to establish whether the deleterious effects of passive stretching seen in laboratory settings would be manifest in a performance setting. Sixteen members (11 males, 5 females) of a Division I NCAA track athletics team performed electronically timed 20 m sprints with and without prior stretching of the legs. The experiment was done as part of each athlete's Monday work-out programme. Four different stretch protocols were used, with each protocol completed on a different day. Hence, the test period lasted 4 weeks. The four stretching protocols were no-stretch of either leg (NS), both legs stretched (BS), forward leg in the starting position stretched (FS) and rear leg in the starting position stretched (RS). Three stretching exercises (hamstring stretch, quadriceps stretch, calf stretch) were used for the BS, FS and RS protocols. Each stretching exercise was performed four times, and each time the stretch was maintained for 30 s. The BS, FS and RS protocols induced a significant (P < 0.05) increase (approximately 0.04 s) in the 20 m time. Thus, it appears that pre-event stretching might negatively impact the performance of high-power short-term exercise. 相似文献
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W L Cornelius K Ebrahim J Watson D W Hill 《Research quarterly for exercise and sport》1992,63(3):311-314
The purpose of the study was to determine the effects of modified Proprioceptive Neuromuscular Facilitation (PNF) flexibility techniques on hip flexion in college males and to determine if local cold application enhances the effectiveness of these techniques. Male subjects (N = 120), with an average age of 21.5 +/- 2.7 years, were randomly assigned to one of four different kinds of stretching treatments with cold or no cold application (15 per group). Range of motion (ROM) in degrees was determined following four stretching techniques: three modified PNF (PCP, 3-PIECP, 3-PIFCP) and a passive stretch (P). Data were analyzed using a 2 (conditions) x 4 (treatments) ANOVA. There were no significant differences in ROM between cold and no cold conditions. Significant differences existed among ROM techniques (p less than .05). Post hoc analyses revealed that the three modified PNF techniques resulted in greater ROM than the passive stretch technique. However, we conclude that cold application does not influence the effectiveness of selected stretching techniques. 相似文献
7.
Introductory textbooks commonly state that Golgi tendon organs (GTOs) are responsible for a reflex response that inhibits a muscle producing dangerously high tension (autogenic inhibition). Review of the relevant data from animal studies demonstrates that there is wide variability in the magnitude of, and even the presence of, GTO autogenic effects among locomotor hindlimb muscles, and that data on GTO effects under conditions of voluntary maximal muscle activation are lacking. A single available study on GTO function in humans, during a moderate contraction, surprisingly shows a reduction in autogenic inhibition during muscle-force production. Further, it is not possible to find experimental evidence supporting the idea that strength training may produce a decrease in GTO mediated autogenic inhibition, allowing greater muscle activation levels and hence greater force production. 相似文献
8.
Gordon Chalmers 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):239-249
Introductory textbooks commonly state that Golgi tendon organs (GTOs) are responsible for a reflex response that inhibits a muscle producing dangerously high tension (autogenic inhibition). Review of the relevant data from animal studies demonstrates that there is wide variability in the magnitude of, and even the presence of, GTO autogenic effects among locomotor hindlimb muscles, and that data on GTO effects under conditions of voluntary maximal muscle activation are lacking. A single available study on GTO function in humans, during a moderate contraction, surprisingly shows a reduction in autogenic inhibition during muscle‐force production. Further, it is not possible to find experimental evidence supporting the idea that strength training may produce a decrease in GTO mediated autogenic inhibition, allowing greater muscle activation levels and hence greater force production. 相似文献
9.
大鼠骨骼肌模拟急性拉伤的生物力学实验研究 总被引：4，自引：1，他引：3
根据现有肌肉急性拉伤动物模型中存在的问题,即:拉伤前肌肉的机能水平低,拉伤过程中肌肉为静息状态、拉伸速率慢、拉伸幅度大等,结合运动实践,复制了肌肉急性拉伤动物模型,并从生物力学角度进行了研究,其结果如下:1)肌肉在收缩状态下拉伤(离心工作),能够影响肌肉中肌纤维与肌鞘(结缔组织)受损比例,结缔组织受损明显增加。2)肌肉的拉伸速率快,为300％的肌纤维长度/s,明显优于其它学者的模型(6.8％～68％)肌纤维长度/s),更好地模拟运动实践中肌肉急性拉伤的状况(400％肌纤维长度/s)。3)肌肉拉伸时的幅度小,为其肌腹长度的24％,在肌肉正常生理运动范围之内;这样不仅符合运动实践中肌肉离心收缩幅度小的特点,而且在模型中也避免了肌肉邻近关节受损的可能性,从而提高了模型的质量。 相似文献
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目的：探索传统武术劲的系统训练方法及科学原理;方法：在对传统武术站桩练劲进行科学创新再指导6名运动员训练;结果：接受站桩训练的学员训练100小时后全身主要肌肉均建立一种反射,此反射能在特定的姿势下被激活,并且此反射被激活后使肌肉贮存弹性势能而增加出拳、出腿的速度和力量;结论：传统武术劲是符合现代生理学的一门科学的运动技术,它的原理就是人体在紧张性牵张反射的基础上通过训练建立的一个高级的运动条件反射。 相似文献
11.
In response to chronic physical training, the human neuromuscular system undergoes significant and specific adaptations. More importantly, these influences are the result of the type and quantity of physical activity. One of the simplest neuromuscular mechanisms is the spinal stretch reflex. The reflex system was previously viewed as inflexible, with a relatively fixed response that could vary only slightly. However, more recent data have identified an adaptive plasticity in the reflex system. In this respect, the reflex system can be used to assess training and aging adaptations of the human neuromuscular system. Due to their methodological simplicity, both the tendon-tap reflex and the electrically evoked Hoffmann reflex (H-reflex) can be used to assess training adaptations of the human neuromuscular system. The purpose of this paper is to review briefly the tendon-tap and H-reflex paradigms and delineate the research findings pertaining to changes in the reflex system with physical training. For purposes of clarity, this discussion will be divided into the following: (a) differences observed in the tendon-tap reflex, (b) differences observed in the H-reflex, and (c) role of interneurons in mediating these changes. 相似文献
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Michael Heuser 《Journal of sports sciences》2013,31(2):219-226
Abstract The objective of this study was to examine the effects of acute static muscle stretch on hamstring muscle fatigue and perceived exertion between young adult men and women. Twenty volunteers participated in two experimental sessions, in which we assessed maximal-effort isokinetic knee flexor force (90° · s?1) and the number of sub-maximal (50% maximal) knee flexor repetitions to the point of failure. Immediately before the sub-maximal contractions on one randomly selected session, participants received ten 30-s passive knee flexor muscle stretches. Perceived exertion was sampled with a modified Borg category-ratio scale following each sub-maximal repetition. Each participant's perceived exertion response was estimated every 10% across the sub-maximal repetitions, via linear interpolation and power-function modelling. The men generated significantly greater force than the women during both experimental sessions, while muscle stretching had no significant effect on the number of sub-maximal repetitions. When estimated via power-function modelling, perceived exertion increased at a significantly greater rate following muscle stretch. Perceived exertion was significantly greater for the women following muscle stretch than the men. The findings suggest that the elevation in perceived exertion following knee flexor muscle stretching may be greater in women than men, despite no significant alterations in mechanical measures of muscle fatigue. 相似文献
13.
《European Journal of Sport Science》2013,13(3):233-241
AbstractThe effects of flexibility conditioning on neuromuscular and sensorimotor performance were assessed near to full knee extension (25°). Eighteen males who were randomly assigned into two groups underwent eight weeks (three-times per week) of flexibility conditioning (hip region/knee flexor musculature; dominant limb) involving either proprioceptive neuromuscular facilitation (PNF) (n=9) or passive stretching (PASS) (n=9). Both modes of flexibility conditioning are popular within contemporary exercise and clinical settings and have demonstrated efficacy in improving range of motion. The contralateral limb and a prior ‘no exercise’ condition were used as controls. The PNF and PASS modes of conditioning improved passive hip flexibility to a similar extent (mean 19.3% vs. baseline, intervention limb, p<0.01) but did not alter knee flexor strength (overall mean 309.6±81 N) or sensorimotor performance (force and positional errors: 2.3±8.2% and 0.48±7.1%). Voluntary and magnetically evoked electromechanical delays (EMDV and EMDE, respectively) were increased but to a greater extent following PASS compared to PNF (PASS: 10.8% and 16.9% lengthening of EMDV and EMDE, respectively vs. PNF: 3.2% and 6.2%, p<0.01).The attenuated change to electromechanical delay (EMD) performance during PNF conditioning suggests a preserved capability for rapid muscle activation, which is important in the maintenance of dynamic joint stability. That PNF was also equally efficacious in flexibility conditioning would suggest that this mode of flexibility training should be used over passive to help preserve dynamic joint stability capabilities at this extended and vulnerable joint position. 相似文献
14.
AbstractGolgi tendon organ disinhibition may contribute to exercise-associated muscle cramp (henceforth referred to as “cramps”) genesis. Static stretching pre-exercise is prescribed to prevent cramps based on the assumption golgi tendon organ inhibition remains elevated post-stretching. We determined whether stretching increased gastrocnemius golgi tendon organ inhibition and, if so, the time course of this inhibition post-stretching. Twelve participants’ dominant limb medial gastrocnemius inhibition was measured before, and at 1, 5, 10, 15 and 30 min after investigators applied three, 1-min duration stretches. Participants maintained voluntary contraction intensities of 5% of their maximum while the Achilles tendon was stimulated transcutaneously 50 times. Five-hundred millisecond epochs of raw electromyographic activity were band-pass filtered, full-wave rectified and averaged. An algorithm identified inhibitory points and calculated the area, maximum and duration of inhibition. Area of inhibition (F1,14 = 1.5, P = 0.25), maximum inhibition (F1,14 = 0.2, P = 0.72) and duration of inhibition (F1,14 = 1.5, P = 0.24) were unaffected by static stretching over the 30-min post-stretching period. If pre-stretching does prevent fatigue-induced cramping, the mechanism is unlikely to involve the autoinhibition produced by the golgi tendon organ reflex. Further empirical research is needed to validate the proposed link between static stretching and cramping and then to investigate alternative mechanisms. 相似文献
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跨栏运动员在准备活动中进行不同拉伸练习对其髋关节柔韧性影响的研究 总被引：1，自引：0，他引：1
为了探讨跨栏运动员有效的拉伸练习方法,通过对45名跨栏运动员进行拉伸练习的比较试验研究,分析跨栏运动员在准备活动中分别进行两种不同的拉伸练习(静力拉伸练习和PFN法拉伸练习)后,其对跨栏运动员柔韧性的影响。结果表明PFN法拉伸练习更能有效提高跨栏运动员的柔韧性。 相似文献
16.
The aim of this study was to investigate the acute effects of prior exercise (warm‐up and stretching) on the electromyographic and force output of mechanically elicited triceps surae reflexes. Fifty male subjects performed eight reflex experiments under each of three successive conditions in one session: (1) no prior exercise, (2) after static stretching of the passive triceps surae (3 min) and (3) after a 10‐min warm‐up run on a treadmill. Tendon tap reflex force was elicited in the triceps surae of the right leg by means of a standardized reflex hammer and measured in a custom‐built fixture. Electromyographic (EMG) signals were recorded with surface electrodes over the medial head of the gastrocnemius (G) and the soleus (S). Low coefficients of variation within subjects contrasted with high between‐subject variations, indicating highly individual reflex characteristics. After stretching, reductions in the peak force (‐5%; P < 0.05), the force rise rate (‐8%; P < 0.01), the half relaxation rate (‐5%; N.S.), the EMG amplitudes (G, ‐16%; S, ‐17%; P < 0.01) and integrals (G, ‐15%; S, ‐18%; P < 0.01), and an increase in EMG latencies (G, +3%; S, +1%; P < 0.01), were found compared with the values obtained without prior exercise. After running, the peak force reached the values obtained without prior exercise (‐2%; N.S.), the force rise rate and half relaxation rate increased by 8 and 12%, respectively (P < 0.01), and the impulse (force‐time integral; ‐12%), EMG amplitudes (G, ‐20%; S, ‐23%; P < 0.01), integrals (G, ‐18%; S, ‐23%; P < 0.01) and latencies (G, ‐1%; S, ‐2%; P < 0.01) decreased significantly. The changes in the force characteristics observed after the stretching treatment indicate improved muscle compliance that might reduce the risk of injury. On the other hand, the changes after the additional warm‐up run had a more pronounced influence with regard to improved force development and a decreased EMG activity, which can be viewed as a performance‐enhancing effect. 相似文献
17.
David M. High Edward T. Howley B. Don Franks 《Research quarterly for exercise and sport》2013,84(4):357-361
Abstract It has been suggested in the lay literature that static stretching and/or warm-up will prevent the occurrence of Delayed-Onset Muscle Soreness (DOMS). The primary purpose of this study was to determine the effects of static stretching and!or warm-up on the level of pain associated with DOMS. Sixty-two healthy male and female volunteers were randomly assigned to four groups: (a) subjects who statically stretched the quadriceps muscle group before a step, (b) subjects who only performed a stepping warm-up, (c) subjects who both stretched and performed a stepping warm-up prior to a step test, and (d) subjects who only performed a step test. The step test (Asmussen, 1956) required subjects to do concentric work with their right leg and eccentric work with their left leg to voluntary exhaustion. Subjects rated their muscle soreness on a ratio scale from zero to six at 24-hour intervals for 5 days following the step test. A 4×2×2 ANOVA with repeated measures on legs and Duncan's New Multiple Range post-hoc test found no difference in peak muscle soreness among the groups doing the step test or for gender (p > .05). There was the expected significant difference in peak muscle soreness between eccentrically and concentrically worked legs, with the eccentrically worked leg experiencing greater muscle soreness. We concluded that static stretching and!or warm-up does not prevent DOMS resulting from exhaustive exercise. 相似文献
18.
以陕西师范大学体育学院2013级36名武术专选生为研究对象,以前俯腰、横叉、纵叉、正踢腿为指标对PNF拉伸法（A组）,动静力结合训练法（B组）,传统的武术下肢柔韧训练方法（C组）的效果进行对比研究。结果表明：经过10周的训练,A、B、C三组学生的各指标成绩均有不同程度的变化,且变化幅度A组>B组>C组。可见,PNF拉伸法是三种训练方法中对提高武术专选生下肢柔韧性最有效的方法。 相似文献
19.
Fabio Esposito Emiliano Cè Susanna Rampichini Arsenio Veicsteinas 《Journal of sports sciences》2013,31(12):1347-1357
Abstract The aim of this study was to assess the effects of acute passive stretching on the electrical and mechanical response of a previously fatigued muscle. Eleven participants underwent maximal tetanic stimulations (50 Hz) of the medial gastrocnemius, before and after a fatiguing protocol and after a bout of passive stretching of the fatigued muscle. During contraction, surface electromyography (EMG), mechanomyography (MMG), and force were recorded. The following parameters were calculated: (1) the EMG root mean square (RMS), mean frequency, and fibre conduction velocity; (2) MMG peak-to-peak and RMS; (3) the peak force, contraction time, half-relaxation time, peak rate of force development (dF/dt) and its acceleration (d2 F/dt 2). Fatigue reduced peak force by 18% (P < 0.05) and affected the other force, EMG, and MMG parameters. After stretching: (1) all EMG parameters recovered to pre-fatigue values; (2) MMG peak-to-peak remained depressed, while RMS recovered to pre-fatigue values; (3) the peak force, peak rate of force development and its acceleration were further reduced by 22, 18, and 51%, respectively, and half-relaxation time by 40% (P < 0.05). In conclusion, acute passive stretching, when applied to a previously fatigued muscle, further depresses the maximum force-generating capacity. Although stretching does not alter the electrical parameters of the fatigued muscle, it does affect the mechanical behaviour of the muscle–tendon unit. 相似文献
20.
Two mechanisms have been suggested to explain stretching-induced maximum force depression: a mechanical alteration in the stretched muscle and an impairment of neural activation. Electrical stimulation allows standardization of the level of muscle activation without being limited by neural control. The aim of this study was to evaluate the stretching-induced changes in the electrical and mechanical properties of muscle during electrically elicited contractions. Twelve participants (age 22 +/- 1 years; body mass 75 +/- 2 kg; stature 1.79 +/- 0.02 m; mean +/- standard error) underwent six electrical stimulations of the medial gastrocnemius muscle before and after stretching. During the contractions, surface electromyogram (EMG) and mechanomyogram (MMG) were recorded simultaneously together with force. After stretching we found: (i) no differences in EMG parameters; (ii) MMG amplitude decreased by 4 +/- 1% (P < 0.05); and (iii) the peak force, the peak rate of force development, and the acceleration peak of force development decreased by 12 +/- 3%, 14 +/- 1%, and 24 +/- 5%, respectively (P < 0.05). In conclusion, acute passive stretching did not change EMG properties but altered the mechanical characteristics of the contracting muscle. Indeed, muscle force-generating capacity and stiffness of the muscle-tendon unit were significantly impaired. 相似文献