Immediate effect of passive hamstring stretching on flexibility and relationship with psychosocial factors in people with chronic low back pain

Background

Hamstring muscle tightness contributes to disability in people with chronic low back pain (CLBP). HM stretching improves flexibility in healthy individuals, but the immediate effect of stretching is unknown in people with CLBP. Moreover, the stretching effect could be influenced by psychosocial factors.

Objectives

To evaluate the immediate effect of passive HM stretching on flexibility in people with CLBP and the relationships between psychosocial factors and change in hamstring flexibility.

Design

Non-randomized, pilot trial.

Method

One minute of passive stretching was performed in 90 people with CLBP. Change in Active Knee Extension and Straight Leg Raise angles (digital inclinometer), and Fingertips-to-Floor distance (measuring tape) were measured before and immediately after stretching. Correlations between change in flexibility and baseline Fear-Avoidance Beliefs Questionnaire (FABQ) and Hospital Anxiety and Depression Scale (HADS) scores were analyzed.

Results

Hamstring flexibility improved significantly after stretching; Active Knee Extension mean difference was 4° (95% CI, 2.4 to 5.1; p < 0.001, right ES = 0.24, left ES = 0.23); Straight Leg Raise mean difference was 7° (95% CI, 5.5 to 8.6, p < 0.001, right ES = 0.44, left ES = 0.42), Fingertips-to-Floor mean difference was 2 cm (95% CI, 1.7 to 3.0, p < 0.001, ES = 0.20). No correlation was found between improvement in any of the hamstring flexibility measurements and FABQ or HADS scores (p > 0.05).

Conclusions

Passive hamstring stretching induced an immediate, statistically significantly improvement in hamstring flexibility, but only the change in Straight Leg Raise amplitude was clinically important. Psychosocial factors were not related to improvements in flexibility after hamstring stretching.

Roles of stretch-activated channels and NADPH oxidase 2 in the induction of twitch contraction by muscle stretching in rat ventricular muscle

Mechano-electric feedback means that muscle stretching causes depolarization of membrane potential. We investigated whether muscle stretching induces action potential and twitch contraction with a threshold of sarcomere length (SL) and what roles stretch-activated channels (SACs) and stretch-activated NADPH oxidase (X-ROS signaling) play in the induction. Trabeculae were obtained from the right ventricles of rat hearts. Force, SL, and [Ca²⁺]_i were measured. Various degrees of stretching from the SL of 2.0 μm were applied 0.5 s after the last stimulus of the electrical train with 0.4-s intervals for 7.5 s. The SL_twitch was defined as the minimal SL at which twitch contraction was induced by the stretching. Muscle stretching induced twitch contraction with a threshold of SL at 0.4-s stimulus intervals ([Ca²⁺]_o = 0.7 mmol/L). The SL_twitch was not changed by increasing the stimulus intervals and [Ca²⁺]_o and by adding 1 μmol/L isoproterenol. The SL_twitch was not changed by adding 10 μmol/L Gd³⁺, 100 μmol/L or 200 μmol/L streptomycin, and 5 μmol/L GsMTx4. The SL_twitch was not changed by adding 1 μmol/L ryanodine and 3 μmol/L diphenyleneiodonium chloride. In contrast, the SL_twitch was increased by elevating extracellular K⁺ from 5 to 10 mmol/L and by adding the stretching during the refractory period of membrane potential. The addition of the stretching-induced twitch contraction more frequently induced arrhythmias. These results suggest that muscle stretching can induce twitch contraction with a threshold of SL and concern the occurrence of arrhythmias and that SACs and X-ROS signaling play no roles in the induction.

Tension Reducing Muscle Stretch Protocol to Obtain Full Distal Tendon Excursion: A New Rehabilitation Protocol after Flexor Tendon Repair

Background: Flexor tendon rehabilitation protocols minimize repair tension by limiting range of movement to prevent tendon rupture. The resultant muscle contracture inhibits finger extension, increases resistance in tendon gliding distally, and progress to proximal interphalangeal (PIP) joint flexion contracture. This study describes our new rehabilitation protocol, the Tension Reducing Muscle Stretch (TRMS), designed to prevent flexor muscle contracture and obtain full distal tendon excursion. Methods: We reviewed retrospectively 14 fingers in 13 consecutive patients with primary repair of complete zone I or II flexor digitorum profundus (FDP) tendon rupture were treated with our protocol between 2007 and 2019. Our rehabilitation following FDP 4-strand repairs consisted of three steps. The first step comprised of exercises from traditional protocols such as Duran, Kleinert, Synergistic-wrist-motion, and Place-and-hold. The second step comprised the TRMS exercise to prevent the onset of muscle contracture. Anatomically, FDP tendons arise from the same FDP muscle belly. TRMS involved placing the affected finger in full passive flexion while unaffected fingers were passively extended to full extension. This made the affected FDP muscle stretched. The final step incorporated the early active flexion motion exercise, in which simple fisting was performed, from a fully extended position. Results: The mean total active motion at the final follow up was 235° (range 170-265). Using the Strickland criteria, eight achieved excellent, four had good, two had fair results. The mean angle of passive extension deficit at the PIP joint at four weeks after surgery was -7° (-30-0), and at the final follow up was -3° (-20-0). No tendon repair was ruptured. Conclusions: This protocol reduced tension in the affected tendon muscle and encouraged tendon excursion distal to the repair site without complications. It allows full tendon excursion and prevents PIP joint contractures.

The effect of isokinetic dynamometer deceleration phase on maximum ankle joint range of motion and plantar flexor mechanical properties tested at different angular velocities

During range of motion (max-ROM) tests performed on an isokinetic dynamometer, the mechanical delay between the button press (by the participant to signal their max-ROM) and the stopping of joint rotation resulting from system inertia induces errors in both max-ROM and maximum passive joint moment. The present study aimed to quantify these errors by comparing data when max-ROM was obtained from the joint position data, as usual (max-ROM_POS), to data where max-ROM was defined as the first point of dynamometer arm deceleration (max-ROM_ACC). Fifteen participants performed isokinetic ankle joint max-ROM tests at 5, 30 and 60° s^-1. Max-ROM, peak passive joint moment, end-range musculo-articular (MAC) stiffness and area under the joint moment-position curve were calculated. Greater max-ROM was observed in max-ROM_POS than max-ROM_ACC (P < 0.01) at 5 (0.2 ± 0.15%), 30 (1.8 ± 1.0%) and 60° s^-1 (5.9 ± 2.3%), with the greatest error at the fastest velocity. Peak passive moment was greater and end-range MAC stiffness lower in max-ROM_POS than in max-ROM_ACC only at 60° s^-1 (P < 0.01), whilst greater elastic energy storage was found at all velocities. Max-ROM and peak passive moment are affected by the delay between button press and eventual stopping of joint rotation in an angular velocity-dependent manner. This affects other variables calculated from the data. When high data accuracy is required, especially at fast joint rotation velocities (≥30° s^-1), max-ROM (and associated measures calculated from joint moment data) should be taken at the point of first change in acceleration rather than at the dynamometer's ultimate joint position.

Daily Passive Muscle Stretching Improves Flow-Mediated Dilation of Popliteal Artery and 6-minute Walk Test in Elderly Patients with Stable Symptomatic Peripheral Artery Disease

BACKGROUND

Patients with peripheral arterial disease (PAD) often have walking impairment due to insufficient oxygen supply to skeletal muscle. In aged rats, we have shown that daily stretching of calf muscles improves endothelium-dependent dilation of arterioles from the soleus muscle and increases capillarity and muscle blood flow during exercise. Therefore, we hypothesized that daily muscle stretching of calf muscles would improve endothelium-dependent vasodilation of the popliteal artery and walking function in PAD patients.

METHODS

We performed a randomized, non-blinded, crossover study whereby 13 patients with stable symptomatic PAD were randomized to undergo either 4 weeks of passive calf muscle stretching (ankle dorsiflexion applied 30 min/d, 5 days/wk) followed by 4 weeks of no muscle stretching and vice versa. Endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent nitroglycerin-induced dilation of the popliteal artery and 6 minute walk test (6MWT) were evaluated at baseline and after each 4 week interval.

RESULTS

After 4 weeks of muscle stretching, FMD and 6MWT improved significantly in the muscle stretching group vs. the control (FMD: 5.1 ± 0.5% vs. 3.7 ± 0.3%, P = 0.005; 6MWT continuous walking distance: 304 ± 43 m vs. 182 ± 34 m; P = 0.0006). No difference in nitroglycerin-induced dilation was found between groups (10.9 ± 1.2 vs. 9.9 ± 0.4%, P = 0.48). Post-stretching, 6MWT total walking distance was positively correlated with normalized FMD (R = 0.645, P = 0.02).

CONCLUSIONS

Passive calf muscle stretching enhanced vascular endothelial function and improved walking function in elderly patients with stable symptomatic PAD. These findings merit further investigation in a prospective randomized trial.

Immediate effects and one-week follow-up after neuromuscular electric stimulation alone or combined with stretching on hamstrings extensibility in healthy football players with hamstring shortening

OBJECTIVE

To assess the immediate and mid-term (after 7 days) effects of electric current combined with simultaneous muscle stretching (EME technique) per comparison to the isolated use of the same current (without applying simultaneous muscle stretching), over the hamstring extensibility in football players with hamstring shortening, and to estimate the clinical benefit of the interventions according to the muscular extensibility.

METHODS

Forty-eight participants were randomized to receive one session of EME technique (n = 26) or one session of the electrical current (EC) alone (n = 22). The measurement of the hamstrings extensibility through the active knee test was carried out before and immediately after each intervention and one week later.

RESULTS

A significant interaction group x time was observed (F_2,84 = 7.112, p = 0.001; partial eta squared = 0.145). The hamstrings extensibility changed significantly immediately after the EME technique (147.3° ± 16.4° to 153.5° ± 14.2°, p < 0.05), but not after the EC only (144.2 ± 10.2° to 141.7 ± 7.8°, p > 0.05). One week after the intervention no significant differences were found to the baseline values in both groups. The number needed to treat to prevent one new case of hamstring shortening was 3.

CONCLUSION

The combination of electric current with simultaneous stretching is an effective technique to acutely increase the hamstring extensibility of football players with hamstring shortness.

Effects of static interventions on disuse atrophy of the rat soleus muscle at different sites along its longitudinal axis

[Purpose] The purpose of our study was to verify the inhibitory effects of static intervention (heat load and muscle stretching) on disuse-related adaptation changes in the soleus muscle and to compare these effects across different sites along its longitudinal axis. [Subjects] Forty 8-week-old male Wistar rats. [Methods] The effects of heat load and/or muscle stretching in the rat soleus during hindlimb suspension were evaluated by measuring the cross-sectional area of the muscle fibers, succinate dehydrogenase activity, and number of capillaries in the proximal, middle, and distal regions. [Results] With no intervention the proximal region showed the highest reduction in the cross-sectional area, whereas the distal region showed the highest reduction in succinate dehydrogenase activity and the number of capillaries due to hindlimb suspension. These differences between the proximal and distal regions decreased with both interventions, and the effects were most pronounced with a combination of heat load and muscle stretching. [Conclusion] Differences in the muscle structure between the proximal and distal regions increased due to hindlimb suspension, and this heterogeneity associated with muscle disuse was inhibited by static intervention including heat load and muscle stretching. Furthermore, the combination of heat load and muscle stretching most reduced the heterogeneity.

The effect of ankle joint muscle strengthening training and static muscle stretching training on stroke patients' C.o.p sway amplitude

[Purpose] This study implement ankle joint dorsiflexion training for ankle muscle the weakness that impairs stroke patients’ gait performance, to examine the effect of the training on stroke patients’ plantar pressure and gait ability. [Subjects and Methods] In this study, 36 stroke patients diagnosed with stroke due to cerebral infarction or cerebral hemorrhage performed the training. Static muscle stretching was performed four times a week for 20 minutes at a time for 6 weeks by the training group. Ankle dorsiflexor training was performed four times a week, two sets per time in the case of females and three sets per time in the case of males for 6 weeks, by another group. Center of pressure sway amplitude was measured using the F-scan system during gait. All subjects were assessed with the same measurements at a pre-study examination and reassessed at eight weeks. Data were analyzed statistically using the paired t-test and one-way ANOVA. [Results] Among the between ankle dorsiflexor training group, static muscle stretching group, and control group, the difference before and after the training were proven to be statistically significant. [Conclusion] Compared to other training groups, the ankle muscle strength training group showed statistically significant increases of forward thrust at stroke patients’ toe-off which positively affected stroke patients’ ability to perform gait.

Genetic stretching factors in masseter muscle after orthognathic surgery

Up to 30% of patients relapse after orthognathic operations, and one reason might be incomplete neuromuscular adaptation of the masticatory muscles. Displacement of the mandible in sagittal or vertical directions, or both, leads to stretching or compression of these muscles. The aim of this study was to analyse stretching factors in 35 patients with retrognathism or prognathism of the mandible (Classes II and III). Tissue samples were taken from both sides of the masseter muscle (anterior and posterior) both before and 6 months after operation. Developmental myosin heavy chains MYH3 and MYH8, the fast and slow MYH 1, 2, and 7, and cyclo-oxygenase (COX) 2, forkhead transcription factor (FOX)O3a, calcineurin, and nuclear factor of activated T cells (NFAT)1c (stretching and regeneration-specific), were analysed by real time polymerase chain reaction (PCR). Correlations of Class II and III with sagittal and vertical cephalometric measurements ANB and ML-NL-angle were examined, and the results showed significant differences in amounts of MYH8 (p<0.05), MYH1 (p<0.05), and FOXO3a (p<0.05) between the 2 groups. Regeneration factor COX2 is more dominant in Class II. Surgically, bite opening (ML/NL angle) correlated with stretching indicators FOXO3a, calcineurin, and NFAT1c only in Class II patients. This means that stretching of the masseter muscle caused by lengthening of the mandible and raising of the bite in Class II patients was more likely to lead to relapse (similar to that in patients with open bite) than in Class III patients. In conclusion, deep bite should be reduced more by incisor intrusion than by skeletal opening. The focus in these patients should be directed towards physiotherapeutic strengthening of the muscles of mastication, and more consideration should be given to change in the vertical dimension.