The Effect of Static Stretching Duration on Muscle Blood Volume and Oxygenation.

ABSTRACT: Matsuo, H, Kubota, M, Shimada, S, Kitade, I, Matsumura, M, Nonoyama, T, Koie, Y, Naruse, H, Takahashi, A, Oki, H, Kokubo, Y, and Matsumine, A. The effect of static stretching duration on muscle blood volume and oxygenation. J Strength Cond Res 36(2): 379-385, 2022-Muscle blood volume increases due to stretching; however, the minimum duration of stretching to sustainably increase the muscle blood volume after stretching has not yet been elucidated. This study examined whether the duration of static stretching influenced the muscle blood volume and oxygenation. Ten healthy male subjects participated in this controlled laboratory study. Static stretching of the gastrocnemius muscle was performed for 5 durations (20 seconds, and 1, 2, 5, and 10 minutes). Changes in both the total-Hb (ΔtHb), as an index of blood volume, and tissue oxygenation index (ΔTOI) from baseline were determined using near-infrared spectroscopy. Both the ΔtHb and ΔTOI decreased during stretching and increased after stretching. The minimum value of ΔtHb during stretching did not differ in each of the 5 durations, but minimum ΔTOI progressively decreased with longer durations of stretching. The peak value of ΔtHb after stretching increased with longer durations of stretching. The value of ΔtHb at 5 minutes after the end of stretching increased with more than 2 minutes of stretching compared with 20 seconds of stretching, although the value of ΔtHb did not significantly differ between the 2, 5, and 10 minutes' durations. These findings suggest that a longer duration of stretching elicits a decrease in muscle oxygenation during stretching, and an increase in both the muscle blood volume and oxygenation after stretching. The results indicated that the minimum duration of stretching to sustain an increase in the muscle blood volume after stretching is 2 minutes.

Center of pressure velocities in patients with body lateropulsion: three case report series of Wallenberg's syndrome.

PURPOSE: In patients with Wallenberg's syndrome who present with body lateropulsion (BL), whether the center of pressure (COP) position and velocity characterize postural dysregulation is unknown. We measured time-course changes in COP parameters in three BL patients. METHODS: Three patients with acute Wallenberg's syndrome presented with BL. COP was measured for time-course changes during first standing and every week thereafter. COP positions, which indicate the deviation in the center of gravity, were calculated. COP velocities associated with dynamic movements of the center of gravity were analyzed separately for the BL and non-BL sides. RESULTS: All patients showed that COP position shifted to the BL side in first standing and changed to the center over time. COP velocities to the BL side were fast in first standing. Two of the three patients had significantly faster COP velocities to the BL side than to the non-BL side (p < .05), and one did not. In all three cases, the faster COP velocities to the BL side decreased significantly after 2 weeks compared to the initial standing position (p < .001). The change seemed to be related to the time when independent walking became possible. CONCLUSIONS: Fast COP velocity to the BL side might reflect postural dysregulation in patients with BL. These findings might be useful information for devising effective rehabilitation in patients with BL.

Kinematic, kinetic, and musculoskeletal modeling analysis of gait in patients with cervical myelopathy using a severity classification.

BACKGROUND CONTEXT: Although a few reports have shown a change in gait motion in cervical myelopathy (CM) patients using a three-dimensional (3D) gait analysis system, there has been no detailed quantitative investigation of their gait including musculoskeletal modeling parameters. Also, 3D gait analysis using a classification of severity has not been substantiated. PURPOSE: This study aimed to investigate kinematic, kinetic, and musculoskeletal modeling parameters of gait motion in CM patients using a severity classification. STUDY DESIGN: Prospective cohort and cross-sectional study. PATIENT SAMPLE: Forty-two patients with CM and 40 healthy, age-matched volunteers. OUTCOME MEASURES: Lower extremity spatiotemporal, kinematic, kinetic, and musculoskeletal modeling parameters. METHODS: Subjects were classified as to its severity using the Japan Orthopaedic Association score excluding the upper extremity items: group 1 (>10 points); group 2 (7-9 points); and group 3 (<6 points). A 3D motion analysis system and musculoskeletal modeling software were used to obtain the spatiotemporal, kinematic (the lower extremity joints angles in the sagittal plane), kinetic (the lower extremity joints moment and power in the sagittal plane), and musculoskeletal modeling parameters (the muscle-tendon length and velocity). RESULTS: Genu recurvatum, deteriorated lower-extremity joint motion, and muscle-tendon velocity were observed in severe CM patients (group 3). Muscle-tendon velocities of the long head of the biceps femoris in controls and mild CM patients (groups 1 and 2) showed a bimodal waveform in the negative direction during the initial contact and preswing phases, whereas these characteristics were not present in severe CM patients (group 3). CONCLUSIONS: The strategies of the knee joint moment during gait motion in severe CM patients were different from those of the normal gait pattern. The imbalance between agonist and antagonist muscle tissue during gait could be involved in the occurrence of genu recurvatum. It might be important for CM patients to consider improving the contraction or extension velocity of the biceps femoris muscle during each gait phase from the early stages of symptoms.

Different therapeutic mechanisms of rigid and semi-rigid mandibular repositioning devices in obstructive sleep apnea syndrome.

To clarify the mechanisms of rigid and semi-rigid mandibular repositioning devices (MRDs) in obstructive sleep apnea syndrome (OSAS), seven and 13 patients received rigid and semi-rigid MRDs, respectively. Each patient underwent polysomnographic and computed tomographic examinations at the initial consultation and after symptom improvement. Three-dimensional models of the upper airway (hard palate level to epiglottic base) were reconstructed by image processing software (Mimics version 14.2) to measure airway morphology. The mean age and body mass index were 58.1 years and 24.8 kg/m(2), respectively, in the rigid MRD group and 57.9 years and 23.2 kg/m(2), respectively, in the semi-rigid MRD group. The apnea-hypopnea index significantly improved (P < 0.05, Wilcoxon signed-rank test) from 22.0 to 8.9 and 20.5 to 11.5 events per hour of sleep in the respective groups. The cross-sectional areas measured at the epiglottic tip (from 2.0 to 2.6 cm(2)) and hard palate (from 2.6 to 3.3 cm(2)) levels also increased in the respective groups (P < 0.05). However, airway volume, cross-sectional area measured at the uvular tip level, and anteroposterior and transverse diameters of the airway were not significantly different. In conclusion, both types of MRDs improve respiratory status, but they affect different parts of the airway.

Efficacy of the Silensor for treating obstructive sleep apnea syndrome.

INTRODUCTION: Although mandibular repositioning devices were found to be very effective for treating obstructive sleep apnea (OSAS), they can cause side effects such as temporomandibular joint disorder and occlusal deviation. A semi-rigid device with a low frequency of side effects, the Silensor, (Erkodent Gmbh, Tuttlingen, Germany) was reported previously. The purpose of this study is to determine whether the Silensor is effective for treating OSAS. MATERIALS AND METHODS: Thirty-five OSAS patients (27 males and 8 females) who were treated with the Silensor were enrolled in this study. The mean age and body mass index of the patients were 52.2 years (23-72 years) and 24.5 kg/m(2) (19.3-31.6 kg/m(2)), respectively. The patients were classified into two groups based on the length of the apparatus connector: 0-2 or 3-4 mm. A polysomnography test was performed twice, at the first visit and after the improvement of subjective symptoms. These data were statistically analyzed using the Wilcoxon signed-rank test. RESULTS: The apnea-hypopnea index significantly improved in all OSAS patients, the mild to moderate OSAS patients, severe OSAS patients, 0- to 2-mm group, and the 3- to 4-mm group (91.4 %; p < 0.01, 88.9 %; p < 0.01, 100 %; p < 0.05, 86.4 %; p < 0.01, 100 %; p < 0.01, respectively). The only side effects of the Silensor were broken apparatus and damage to the buccal mucosa. DISCUSSION: The Silensor is useful for the treatment of OSAS. In particular, the Silensor is suitable for the first phase of OSAS treatment with oral appliances because the efficacy of the Silensor was equal to that of other oral appliances and had few side effects.

Quantitative gait analysis of patients with bilateral hip osteoarthritis excluding the influence of walking speed.

BACKGROUND: The purpose of this study was to investigate gait characteristics of patients with bilateral hip osteoarthritis (BHO) independent of walking speed. METHODS: We measured gait parameters in 12 BHO patients during free walking activities and in 12 normal adults during both free walking and slow walking activities using a three-dimensional computerized gait analysis system. RESULTS: Patients with BHO had a lower walking speed, step length, and cadence than normal subjects during free walking. When compared with normal subjects walking at a slow speed, the walking speed difference among BHO patients disappeared, although BHO patients retained a relatively high cadence. Kinematic and kinetic factor analysis of BHO patients at free speed compared to normal subjects walking at a slow speed showed a forward-tilted pelvic angle in the BHO patients that dropped to that of the ipsilateral side during the stance phase. The peak extension and abduction angle of the hip and the peak abduction moment of the hip were all low, whereas the peak generation power of the ankle was high in BHO patients. CONCLUSIONS: Gait characteristics of patients with BHO, independent of walking speed, were as follows: (1) increased cadence and ankle generation power; (2) reduced step width, hip extension, and abduction angle as well as a lower hip abduction moment; (3) maintained forward tilting of the pelvis during gait cycle; and (4) appearance of a dropped pelvis during the stance phase.