Influence of stretch-shortening cycle on mechanical behaviour of triceps surae during hopping.

Six subjects performed a first series of vertical plantar flexions and a second series of vertical rebounds, both involving muscle triceps surae exclusively. Vertical displacements, vertical forces and ankle angles were recorded during the entire work period of 60 seconds per series. In addition, expired gases were collected during the test and recovery for determination of the energy expenditure. Triceps surae was mechanically modelled with a contractile component and with an elastic component. Mechanical behaviour and work of the different muscle components were determined in both series. The net muscular efficiency calculated from the work performed by the centre of gravity was 17.5 +/- 3.0% (mean +/- SD) in plantar flexions and 29.9 +/- 4.8% in vertical rebounds. The net muscle efficiency calculated from the work performed by the contractile component was 17.4 +/- 2.9% in plantar flexions and 16.1 +/- 1.4% in vertical rebounds. These results suggest that the muscular efficiency differences do not reflect muscle contractile component efficiency but essentially the storage and recoil of elastic energy. This is supported by the relationship (P less than 0.01) found in vertical rebounds between the extra work and the elastic component work. A detailed observation of the mechanical behaviour of muscle mechanical components showed that the strategy to maximize the elastic work depends also on the force-velocity characteristics of the movement and that the eccentric-concentric work of the contractile component does not always correspond respectively to the ankle extension-flexion.     

家兔小腿三头肌亚部化研究

目的：探讨家兔小腿三头肌的亚部划分及该肌的功能。方法：Sihler肌内神经染色法；肌构筑法；肌纤维分型法。结果：从肌内神经的走行进一步证实兔腓肠肌外侧头3个亚部的假设。肌构筑研究显示腓肠肌外侧头慢行时以远端的中间亚部活动为主，快行时有近端的内、外侧亚部更多参与。肌球蛋白ATPase分型研究表明腓肠肌外侧头的3个亚部和腓肠肌内侧头均以ⅡB型纤维居多，比目鱼肌以Ⅰ型纤维占绝对优势。结论：Sihler染色法划分骨骼肌亚部更直观、可靠；腓肠肌外侧头外侧亚部以产生力量，内侧亚部以发挥速度为主；腓肠肌内侧头主要是维持膝在静力和动力状态下的稳定性；比目鱼肌的功能在兔表现不明显。     

Effects of exhaustive stretch-shortening cycle exercise on muscle blood flow during exercise

Aim: The influence of exhaustive stretch‐shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown. Methods: Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin‐1‐beta (IL‐1β) mRNA level determinations. Results: All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decrease in maximal isometric contraction force (MVC) and increase in serum creatine kinase activity (CK) (P = 0.018). After SSC muscle BF was 25% higher in entire QF (P = 0.043) and in its deep and superficial muscle regions, whereas oxygen uptake remained unchanged (P = 0.893). Muscle biopsies revealed increased IL‐1β (30 min: 152 ± 75%, P = 0.012 and 2 days: 108 ± 203%, P = 0.036) but decreased or unchanged eNOS (30 min; ?21 ± 57%, P = 0.050 and 2 days: +101 ± 204%, P = 0.779) mRNA levels after SSC. Conclusion: It was concluded that fatiguing SSC exercise induces increased muscle BF during exercise, which is likely to be associated with pro‐inflammatory processes in the exercised muscle.     

Comparison of the histochemical and contractile properties of human triceps surae

Summary Contractile and histochemical properties of the triceps surae were compared in 16 males and 4 females aged 20 to 49 years. Surface electrical stimulation was used to determine twitch, tetanic and fatigue parameters. From these tests, twitch tension (Pt), time to peak tension (TPT), half relaxation time 1/2 RT), tetanic tensions at 10, 20 and 50 Hz and an index of fatigue (FI) were calculated. A maximal voluntary contraction (MVC) was also performed. Muscle samples from the belly of the lateral gastrocnemius were obtained using the needle biopsy technique. The samples were treated histochemically for myosin ATPase and NADH-tetrazolium reductase in order to classify the fibres as either Type I, slow twitch (ST) or Type II, fast twitch (FT) and to determine fibre areas. Correlations were performed between the grouped male and female contractile and histochemical variables. The results demonstrated significant positive relationships between percentage of ST fibres (%ST) and TPT (r=0.49), and %ST and the ratio of tetanic forces at 10 Hz to 50 Hz (Po10/Po50) (r=0.55). No significant relationships were obtained for Pt, 1/2 RT, MVC or FI with any histochemical parameter. The results suggest that fibre type distribution determined using myosin ATPase is related to electrically stimulated isometric contractile speeds and not to voluntary force generation (MVC) or electrically induced fatigue.     

Comparison of the histochemical and contractile properties of human triceps surae

The purpose of the study was to compare the contractile properties determined from an electrically stimulated twitch with histochemically determined fibre type parameters of the human triceps surae. Muscle samples were obtained from the medial head of the gastrocnemius of ten male athletes. Ages ranged from 20 to 29 years. Muscle samples from the belly of the medial gastrocnemius muscle were obtained using the needle biopsy technique. The samples were treated histochemically for myosin ATPase to classify the fibres as either slow twitch (ST) or fast twitch (FT) and to determine fibre areas. Surface electrical stimulation was used to determine muscle twitch parameters. The contractile variables of the muscle twitch were latency (L), time to peak force (TPF), peak force (PF), half-contraction time (1/2 CT) and half-relaxation time (1/2 RT). Backward elimination procedures for dependent variables were used to determine which contractile properties best represented the histochemical profile of the muscles. Prediction formulas were developed for FT and ST percentages (R²=0·98, p<0·001), relative area percentage (R²=0·87, p<0·001), and ST area (R²=0·85, p<0·01). It was concluded that the use of the electrotensiometer (ETM) protocol was a valid testing procedure when studying physiological relationships of histochemical properties in intact human skeletal muscle. Protected by patent no. 4 688 581.     

彩色多普勒超声对小腿三头肌内静脉扩张的诊断价值

目的探讨彩色多普勒超声对小腿三头肌内静脉扩张的诊断价值。方法选择72例疑为下肢深静脉病变的患者,其中男性32例,女性40例;年龄28-92岁,平均年龄56岁。应用彩色多普勒超声检查小腿三头肌内静脉（包括比目鱼肌静脉及腓肠肌静脉）,测量其管径,观察管腔内透声及血流情况,探查其交通支的情况。结果共检出小腿三头肌内静脉受累患肢72条,单纯小腿三头肌内静脉扩张32例（44．4％）,合并血栓16例（22．2％）,合并交通静脉扩张24例（33.3％）。结论彩色多普勒超声能够有效地检出小腿三头肌内静脉扩张及血栓、其交通支情况。是超声检查下肢深静脉时不容忽视的重要内容。     

Voluntary activation and mechanical performance of human triceps surae muscle after exhaustive stretch-shortening cycle jumping exercise

The purpose of this study was to examine neuromuscular factors that may contribute to post exercise force loss and subsequent recovery after exhaustive stretch-shortening cycle (SSC) exercise. Six subjects were fatigued on a sledge apparatus by 100 maximal rebound jumps followed by continuous submaximal jumping until complete exhaustion. Exercise-induced changes in neuromuscular performance were followed up to 7 days post exercise. The total number of jumps in the SSC exercise ranged from 336 to 1392. The SSC exercise induced a significant immediate plantarflexion torque decline of 29, 38 and 44% (P<0.05) in maximal voluntary contraction and evoked maximal twitch and low-frequency (LF) stimulation, respectively. The higher the number of jumps in the SSC exercise the larger was the post exercise reduction in voluntary activation as well as in contractile force (r=–0.94, P<0.01, in both). Furthermore, a higher number of jumps augmented a delayed force recovery and late decline in stretch reflex EMG response (r=–0.94, P<0.01). Clear differences were found in central and peripheral adaptation to the exhaustive SSC exercise between the subjects. The magnitude of post exercise contractile and activation failure as well as the delayed recovery of neuromuscular performance may have been augmented in some subjects due to their high number of jumps in the exercise.     

Identification of time-varying dynamics of the human triceps surae stretch reflex

We examined the time-varying dynamics of the human triceps surae stretch reflex before, during, and after a large stretch was imposed upon the ankle joint, during a constant voluntary contraction of 15% of maximum voluntary contraction. Stretch reflex dynamics were estimated by superimposing a small stochastic displacement on many such stretches and using an ensemble-based time-varying identification procedure to compute impulse response functions relating the perturbation to the evoked electromyogram (EMG) at each point throughout the task. We found that stretch reflex magnitude (relating joint velocity to EMG) varied directly with baseline EMG activity during steady-state conditions before and after the large imposed stretch. Following the large stretch and the reflex activity it evoked, both background EMG and stretch reflex magnitude declined for up to 100 ms; changes in the stretch reflex were substantially greater in magnitude and followed a different time course from the corresponding changes in background EMG, however, indicating that stretch reflex properties were modulated independently of motoneuron pool activation level. Based on timing and the invariance of stretch reflex dynamics across time, it is argued that this behavior is largely mediated via peripheral neural mechanisms. This peripheral modulation of the stretch reflex presumably supplements various descending influences to adjust reflex properties.     

Effect of electrical stimulation training on the contractile characteristics of the triceps surae muscle

Summary This study aimed to assess the effects of training using electrical stimulation (ES) on the contractile characteristics of the triceps surae muscle. A selection of 12 subjects was divided into two groups (6 control, 6 experimental). The ES sessions were carried out using a stimulator. Flexible elastomer electrodes were used. The current used discharged pulses lasting 200 s at 70 Hz. Contraction time was 5 s and rest time 15 s. The session lasted 10 min for each muscle. Training sessions were three times a week for 4 weeks. Biomechanical tests were performed using an isokinetic ergometer. Subjects performed plantar flexions of the ankle over a concentric range of movement at different angular velocities (60, 120, 180, 240, 300, 360°·s^–1) and held isometric contractions for 5 s at several ankle flexion angles (–30/–15/0/15°–0 corresponded to foot flexion of 90° relative to the leg axis). The force-velocity relationship was seen to shift evenly upwards under the influence of ES (P<0,05). The increased force during the after test was greater (P<0,05) for ankle angle positions of 15° and –30°, which demonstrated a link between the training angle and the gain in strength. No change was noted in the cross-sectional area of the muscle. The results showed that ES allowed the contractile qualities of muscle to be developed in isometric and dynamic conditions. Nervous mechanisms can account for most of these adaptations.     

EMG-activity and muscular performance of lower leg during stretch-shortening cycle after cooling

To test the effect of cooling on EMG-activity of muscles working as an agonist and antagonist in the lower leg, 12 men dressed in shorts and jogging shoes performed a drop-jump exercise after 60 min exposures to 27 °C and 10 °C. Cooling decreased mean skin temperature 5.6±0.4 °C (mean±SD, P<0.001), whereas rectal temperature was unaffected. The muscle temperature measured from m. gastrocnemius medialis decreased 4.1±0.3 °C (P<0.01) at the depth of 30 mm below skin surface. To find the optimal stretching velocity for potentiation of elastic energy, the drop-jump exercise was performed from six different bench heights (10, 20, 30, 40, 50 and 60 cm). The optimal velocity was not altered on account of cooling. In cooled subjects during the stretch phase of the drop jumps the EMG-activity of m. triceps surae complex (agonist) increased (P<0.05–0.001) while the activity of m. tibialis anterior (antagonist) remained unchanged. After cooling during the shortening phase of the jumps the EMG-activity of m. triceps surae complex decreased (P<0.05–0.001), whereas the activity of m. tibialis anterior increased (P<0.05–0.001). In addition, after cooling the peak EMG-activity appeared on the average 28 ms earlier, which shifted the peak activity from the shortening phase (at 27 °C) to the stretch phase (at 10 °C). Cooling increased the mean duration of stretch and shortening phases by 28±3 ms (P<0.001) and 23±2 ms (P<0.001), respectively. The average force production during the shortening phase was 26% less (P<0.05) after cooling, which resulted in a decreased rise of body centre of gravity (P<0.05–0.01). It is concluded that during a stretch-shortening cycle cooling alters the EMG-activity of agonist and antagonist muscles on a contradictory manner and results in an earlier peak EMG-activity. Therefore, alterations in motor unit recruitment could be responsible for the prolonged muscle contraction and decreased force production on account of cooling.     

The mechanical effectiveness of short latency reflexes in human triceps surae muscles revealed by ischaemia and vibration

Summary The resistance to stretch provided by short latency (SL) reflexes in human triceps surae muscles was investigated under three experimental conditions: control, ischaemia, and with 100 Hz vibration applied to the Achilles tendon. Incremental changes in plantar flexion force always showed a strong initial resistance followed by yielding in response to rapid dorsiflexion of the foot about the ankle joint. These changes were attributed to inherent stiffness of the triceps surae muscles. The force curves for each experimental condition diverged during the yield phase some 20 ms after the onset of SL EMG reflexes. During ischaemia, SL EMG reflexes were reduced to 8% of control values and yielding continued until the onset of medium latency EMG activity whereas the yielding was interrupted by SL action in the control situation. The difference between the ischaemia and control force curves was attributed to force recruited by SL reflexes under normal stretch conditions. Vibration reduced the SL EMG reflex amplitude to 20% of control values and produced with it a reduced force response.Supported by the Swiss National Science Foundation grants no. 3.585.79 and 3.505.79, the Dr. Erik Slack-Gyr Foundation, the Sandoz Foundation, and Deutsche Forschungsgemeinschaft grant SFB 70     

Combined effect of elastic energy and myoelectrical potentiation during stretch-shortening cycle exercise

In addition to the utilization of muscle's elastic energy enhancement of performance in exercise involving stretch-shortening cycle might be also due to simultaneous increase of myoelectrical activity. This hypothesis was tested by examining three athletes during jumping exercise on force-platform. Vertical jumps were performed with and without preliminary counter-movement, and the jumps were called counter-movement jump (CMJ) and squatting jump (SJ), respectively. In both conditions several jumps were performed also with extra loads on the shoulders (15–220% of b. wt.). Additional droppingjumps (DJ) were executed from different heights (20–100 cm). During jumping exercise myoelectrical activity of selected muscles from the quadriceps femoris was monitored with surface electrodes. The results obtained were similar to those reported in isolated muscle and as expected, the prestretch in CMJ shifted the force-velocity curve of concentric work to the right. In two cases enhancement of performance was attributed primarily to restitution of elastic energy because myoelectrical activity was similar to that observed in SJ. In one subject increased myoelectrical activity was observed during the concentric phase of CMJ. In DJ condition the EMG activity during eccentric phase was much higher than in SJ. Therefore the high performance in this condition was attributed to both elastic energy and reflex potentiation. In eccentric work of CMJ the average force decreased with the increase of stretching speed. This phenomenon was associated with a light increase of EMG activity. The observed results emphasize that both elastic energy and reflex potentiation may operate effectively during stretch-shortening cycle activity.     

Influence of falling height on the excitability of the soleus H-reflex during drop-jumps

Aim: The stretch‐shortening cycle (SSC) is characterized by stretching of the target muscle (eccentric phase) prior to a subsequent shortening in the concentric phase. Stretch reflexes in the eccentric phase were argued to influence the performance of short lasting SSCs. In drop‐jumps, the short latency component of the stretch reflex (SLR) was shown to increase with falling height. However, in jumps from excessive heights, the SLR was diminished. So far, it is unclear whether the modulation of the SLR relies on spinal mechanisms or on an altered fusimotor drive. The present study aimed to assess the spinal excitability of the soleus Ia afferent pathway at SLR during jumps from low height (LH – 31 cm) and excessive height (EH – 76 cm). Methods: In 20 healthy subjects (age 25 ± 3 years), H‐reflexes were timed to occur at the peak of the SLR during drop‐jumps from LH and EH. Results: H‐reflexes were significantly smaller at EH than at LH (P < 0.05). Neither soleus and tibialis anterior background EMG nor the size of the maximum M‐wave changed with falling height. Conclusion: Differences in the H‐reflex between EH and LH indicate that spinal mechanisms are involved in the modulation of the SLR. A decreased excitability of the H‐reflex pathway at EH compared with LH is argued to serve as a ‘prevention strategy’ to protect the tendomuscular system from potential injuries caused by the high load. It is argued that pre‐synaptic inhibition of Ia afferents is most likely responsible for the change in H‐reflex excitability between the two jump conditions.     

The mechanical efficiency of locomotion in men and women with special emphasis on stretch-shortening cycle exercises

Summary The mechanical efficiency of the leg extensor musculature of men and women was examined with a special sledge ergometer. The subjects (ten males and ten females) performed (a) pure positive work, (b) pure negative work and (c) a combination of negative and positive work (strech-shortening cycle). The mechanical efficiency of pure positive work was on average 19.8±1.2% for female subjects and 17.4±1.2% for male subjects (t=4.12, P<0.001), although the work intensity was equal in both groups. The mechanical efficiency of pure negative work was slightly lower in women than in men (59.3±14.4% vs 75.6±29.3%). The mechanical efficiency of positive work (₊) in a stretch-shortening cycle exercise was 38.1±6.8% in men and 35.5±6.9% in women. The utilization of prestretch was better for female subjects at low prestretch levels, whereas males showed greater potentiation of elastic energy at higher prestretch levels. Regarding absolute W _el (work due to elasticity) values, male subjects showed greater (P<0.001) values than females (189±44 J vs 115±36 J, respectively). Fundamental differences in neuromuscular functions in men and women might cause the differences in the results obtained.     

利用神经入肌点定位小腿三头肌痉挛的神经阻滞靶点

目的　准确定位小腿三头肌的神经入肌点（N点）位置,为临床该肌痉挛神经阻滞提供解剖学基础。 方法　10具20侧成年人尸体下肢,俯卧。紧贴皮肤连接股骨外上髁与内上髁和股骨外上髁与外踝的线分别为N点的横向参考线（H线）和纵向参考线（L线）。解剖暴露小腿三头肌各神经肌支的N点,涂抹硫酸钡,CT扫描。Syngo系统下确定N点在体表的投影点（P点）;P点通过N点后投射至对侧皮肤上的P'点;经P点的垂线与H线、水平线与L线的交点分别记为PH和PL。分别测量PH和PL在H和L线上的百分位置及N点的深度。 结果　腓肠肌内侧头、外侧头和比目鱼肌的PH分别位于H线的（46.89±2.73）%、（40.90±3.05）%和（42.56±2.59）%处,PL分别位于L线的（7.58±2.88）%、（8.15±2.52）%和（17.42±3.31）%处;N点深度分别位于PP'线的（16.32±2.52）%、（13.83±1.77）%和（29.93±2.89）%处。 结论　这些参数可提高小腿三头肌痉挛神经溶解术的疗效和效率。     

Influence of training background on the relationships between plantarflexor intrinsic stiffness and overall musculoskeletal stiffness during hopping

The aim of this study was to characterize the influence of intrinsic musculotendinous and musculoarticular stiffness of plantarflexor muscles on (1) the overall musculoskeletal stiffness and (2) the performance during stretch-shortening cycles-type exercise. The influence of plyometric training background on these relationships was also analyzed. Musculotendinous (SI_MT), passive (K _P ) and active (SI_MA) musculoarticular stiffnesses were quantified, using quick-release and sinusoidal perturbation tests, on nine French elite long or triple jumpers (athlete group, AG) and nine control subjects (CG). These ergometric parameters were related with the lower-limb stiffness (K _leg) and the maximal performance (H _max) measured from a force platform during vertical hopping. AG showed a significantly higher SI_MT (2.76 rad⁻¹), K _P (55.6 N m rad⁻¹), K _leg (30.3 kN m⁻¹) and H _max (0.48 m) compared to CG (1.83 rad⁻¹, 37.8 N m rad⁻¹, 19.6 kN m⁻¹ and 0.38 m, respectively). K _leg was not significantly correlated with any of the intrinsic stiffness parameters (SI_MT, SI_MA or K _P ). For AG, a strong and negative correlation was observed between H _max and K _leg. These data indicate that, while elite jumpers presented higher stiffness of both musculotendinous and passive musculoarticular structures, a high compliance of musculoskeletal system was beneficial to optimize the performance in vertical hopping for these athletes. We suggested that neuromuscular strategies were designed to counterbalance this higher intrinsic stiffness to solve the problem of the conflicting requirement of the musculotendinous elements: increase in compliance to enhance the elastic recoil and increase in stiffness for a better force transmission to the periphery.     

Contractile properties of the human triceps surae muscle during simulated weightlessness

The effect of a 120-day period of bed rest on the mechanical properties of human triceps surae muscle was studied in a group of male volunteers (n = 6, mean age 38 years). The results shows that the contractile properties of skeletal muscle in response to disuse change considerably. Time to isometric peak tension of the triceps surae muscle increased from 120 (SEM 3.0) ms to 136 (SEM 2.9) ms (P < 0.01), half relaxation time from 92 (SEM 2.1) ms to 100 (SEM 1.6) ms (P < 0.05) and total contraction time from 440 (SEM 9.9) ms to 540 (SEM 18.7) ms (P < 0.001). Isometric twitch force (F _t) decreased by a mean of 36.7% (P < 0.05), maximal voluntary contraction (MVC) and maximal force (F _max) by a mean of 45.5% and 33.7%, respectively (P < 0.05-0.01). The valueF _max:F _t ratio increased by 3.6% (nonsignificant). The difference betweenF _max and MVC, expressed as a percentage ofF _max and referred to as force deficiency, has also been calculated. Force deficit increased by a mean of 60% (P < 0.001) after bed rest. Force-velocity properties of the triceps surae muscle calculated according to an absolute scale of voluntary and electrically evoked contraction development decreased considerably. The calculations of the same properties on a relative scale did not differ substantially from the initial physiological state. The results would suggest that muscle disuse is associated with both atrophy and a reduction in contractility in the development ofF _max and decreased central (motor) drive. The change in the triceps surae muscle contractile velocity properties may indicate changes in the kinetically active state in the muscles.     

Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

Elderly people (age 75 years; n=48 males and 34 females) were studied in order to elucidate gender differences in elderly subjects on the determinants of muscle power (force and velocity) during a stretch-shortening cycle. All subjects performed three maximal counter-movement vertical jumps using both legs, on a force platform (Kistler 9281 B). The eccentric (Ep) and concentric (Cp) phases of the jumps were analyzed. The Ep was further divided into an acceleration phase (Ep_acc: from the start of the downward movement to the maximal negative velocity) and deceleration phase (Ep_dec: from the maximal negative velocity to the end of the downward movement). Jump height for the men was higher than for the women (P < 0.001). During both Ep_acc and Ep_dec no significant differences were observed between males and females in force and power generation. However, the men had a higher peak muscle power during the Cp, which may be explained exclusively by the velocity determinant (P < 0.001). No specific gender-related strategy appeared to influence the motor pattern of the movement. The comparable eccentric force generation of the leg extensors in both genders suggests a similar ability to cope with eccentric muscle actions during everyday activities. In contrast, the marked lower capacity for concentric contractions in women may result in an impaired performance, especially in activities where intense and rapid movements are essential, for example when reversing a forward fall. This may be one reason why elderly women are more prone to falls than are elderly men. Accepted: 19 September 2000     

Effect of Foot and Ankle Immobilization on Leg and Thigh Muscles' Volume and Morphology: A Case Study Using Magnetic Resonance Imaging

Our aim was to determine the time course of any changes in muscle volume and shape in the lower limbs following immobilization. A healthy young woman (29 years) had suffered a fracture of the fifth metatarsal of the right foot. MRI scanning of her right thigh and calf muscles had been performed 1 month before the injury (Pre) during a scan initially planned as a teaching tool, 2 days following a 4‐week immobilization period (Post), and after a 2‐month recovery period (Post+2). The results show muscle volume decrements in the triceps surae (TS), quadriceps (Quad), and hamstring (Ham) of 21.9%, 24.1%, and 6.5%, respectively, between the Pre and Post measurements. At Post+2, the Quad and TS muscle volumes were still 5.2% and 9.5% lower, compared with the Pre data. The Ham muscle volume, however, was 2.7% greater than at the Pre phase. Following recovery, the increase in individual TS muscles volume was limited to both proximal and medial (with respect to the knee joint) segments of the muscles. These results indicate very substantial and rapid losses in muscle volumes, both proximally and distally to the immobilization site. The results also show that recovery is far from complete up to 2 months post cast removal. The results have implications for the requirements for rehabilitation for orthopedic patients. Anat Rec, 2008. © 2008 Wiley‐Liss, Inc.