Four weeks of lower-limb static stretching reduces regional arterial stiffness in middle-aged and older women.

PURPOSE: This study aimed to clarify whether habitual lower-limb stretching intervention reduces regional arterial stiffness at the stretched site in middle-aged and older women. METHODS: In this study, the effects of 4 weeks of lower-limb static stretching (of the hip extensor and flexor, knee extensor and flexor, and plantar flexor muscles) were investigated on systemic, central, and peripheral arterial stiffness using pulse wave velocity in 14 healthy middle-aged and older women randomly assigned to either a sedentary control group (67.3 ± 5.6 years; n = 7) or a stretching intervention group (63.4 ± 6.4 years; n = 7). RESULTS: The femoral-ankle pulse wave velocity (an index of peripheral arterial stiffness) significantly decreased in the intervention group (pre, 1222.4 ± 167.5 cm/s; post, 1122.0 ± 141.1 cm/s) but did not change in the control group (pre, 1122.7 ± 107.7 cm/s; post, 1139.9 ± 77.5 cm/s). However, the brachial-ankle pulse wave velocity as an index of systemic arterial stiffness (control: pre, 1655.7 ± 296.8 cm/s, post, 1646.4 ± 232.1 cm/s; intervention: pre, 1637.6 ± 259.9 cm/s, post, 1560.8 ± 254.7 cm/s) and the carotid-femoral pulse wave velocity as an index of central arterial stiffness (control: pre, 1253.6 ± 346.4 cm/s, post, 1223.6 ± 263.4 cm/s; intervention: pre, 1125.4 ± 204.7 cm/s, post, 1024.9 ± 164.5 cm/s) did not change in either group. CONCLUSION: These findings suggest that lower-limb stretching interventions may reduce regional arterial stiffness at the stretched site.

Acute effects of the different relaxation periods during passive intermittent static stretching on arterial stiffness.

To clarify whether the relaxation period during stretching affects the degree of elevated shear rate and the degree of reduction of arterial stiffness, we examined relaxation duration to build an adequate stretching protocol. In Experiment 1, the changes in cardiac output, the shear rate in the posterior tibial artery, and blood volume in the calf muscle were measured during recovery (0-60 s) from a single bout of one-legged passive calf stretching in 12 healthy young men. In Experiment 2, the effects of different relaxation periods (5-, 10-, 20-, and 60-s) of passive one-legged intermittent calf stretching (30-s × 6 sets) on the femoral-ankle pulse wave velocity (faPWV) as an index of peripheral arterial stiffness were identified in 17 healthy young men. As a result, the stretched leg's shear rate significantly increased from 0 to 10th s after stretching. The muscle blood volume in the stretched leg significantly reduced during stretching, and then significantly increased during the recovery period after stretching; however, cardiac output remained unchanged during stretching and recovery. Additionally, the reduction in faPWV from the pre-stretching value in the stretched leg was significantly larger in the protocol with 10-s and 20-s relaxation periods than that in the non-stretched leg, but this did not differ in the 5-s and 60-s relaxation periods. These findings suggest that the relaxation periods of intermittent static stretching that cause a high transient increase in shear rate (via reperfusion after microvascular compression by the stretched calf muscles) are effective to reduce arterial stiffness.

Acute effect of passive one-legged intermittent static stretching on regional blood flow in young men.

PURPOSE: Passive stretching reduces stiffness in the lower limb arteries of the stretched limb. To address this physiological mechanism, we measured the change in shear rate in the posterior tibial artery during a single bout of one-legged passive calf stretching compared with that in the non-stretched leg. METHODS: The diameter, mean blood velocity, blood flow, and shear rate in the posterior tibial artery were measured using Doppler ultrasound before (baseline), during, and after a one-legged passive intermittent calf stretching procedure (six repetitions of 30-s static stretch with 10-s relaxation) in nine healthy young men. RESULTS: In the posterior tibial artery of the stretched leg, the arterial diameter significantly decreased from baseline during the stretching period (baseline vs. stretching period of the 6th set, 0.19 ± 0.01 vs. 0.18 ± 0.01 cm, P < 0.05) without any change in shear rate and mean blood velocity. In contrast, during the relaxation period, the mean blood velocity (baseline vs. relaxation period of the 5th set, 2.98 ± 0.54 vs. 6.25 ± 1.48 cm/s) increased, and consequently, the shear rate (baseline vs. relaxation period of the 5th set, 66.75 ± 15.39 vs. 122.85 ± 29.40 s-1) increased (each P < 0.01); however, there was no change in arterial diameter. In contrast, these values in the non-stretched leg were unchanged at all-time points. CONCLUSIONS: The stretching procedure increased the shear rate in the peripheral artery of the stretched leg during the relaxation period. This finding indicates that the local hemodynamic response (possibly through endothelial function), resulting from an increase in shear stress, may contribute to stretching-induced attenuation of local arterial stiffness.

Association among social-networking service usage via smartphone, internet addiction, and psychological stress in Japanese physical therapy university students: a single-university cross-sectional study.

[Purpose] This study aimed to examine the influence of social-networking service usage via smartphone on internet addiction and psychological stress in Japanese university students studying physical therapy. [Participants and Methods] This single-university cross-sectional study involved 247 physical therapy students in the second to fourth years (ages 19 to 22). By use of self-administered questionnaires, we collected information on daily time of smartphone usage, social-networking service usage via smartphone, and daily self-learning time outside of class hours. We assessed internet addiction and psychological stress using the Internet Addiction Test and Stress Response Scale-18, respectively. After excluding twelve participants, we analyzed the data collected for the other 235. [Results] Multiple regression analysis showed an association of the Internet Addiction Test score with gender and daily time of smartphone usage. "Surfing without any purpose", which is one of the purposes of social-networking service usage, and the Internet Addiction Test score were associated with the Stress Response Scale-18 score. Other variables were not associated with the Internet Addiction Test or Stress Response Scale-18 scores. [Conclusion] Our results suggest that gender (males), longer time of smartphones usage, or using social-networking service usage passively cause internet addiction or psychological stress in Japanese physical therapy university students.

Comparison of respiratory muscle strength in individuals performing continuous and noncontinuous walking exercises in water after the 6-week program.

This study aimed to compare respiratory muscle strength in individuals performing continuous and noncontinuous walking exercises in water after the 6-week program. Twenty-nine healthy men were randomly divided into a continuous group (CG, n=14) and a noncontinuous group (NG, n=15). Firstly, both groups executed the 6-week program which set them to walk for 30 min, 4 times per week, over 6 weeks in a pool with the adjusted intensity that their walking speed increased the heart rate to 60% of the predicted maximum. After the 6-week program, participants in the CG continued the water-walking program for 4 weeks while those in the NG discontinued the water-walking program. In both groups, respiratory muscle strength evaluated by maximum inspiratory pressure (PImax) and maximum expiratory pressure (PEmax) increased significantly after the 6-week program compared with pre-exercise value. Compared to the value after the 6-week program, PEmax increased significantly in the CG after 10 weeks (P<0.05), but the PImax showed no significant change. Compared to the value after the 6-week program, after 10 weeks, in the NG, PEmax decreased significantly, with a considerable decrease after 9 and 10 weeks compared to the CG (P<0.05). The PImax in the NG significantly decreased after 10 weeks from the value observed after the 6-week program. We demonstrated that 6 weeks of walking in water at 60% of the predicted maximum heart rate enhances PImax and PEmax, and that PImax and PEmax decrease in 4 weeks without a water-walking program.

Acute effect of stretching one leg on regional arterial stiffness in young men.

PURPOSE: Our previous study demonstrated that a single bout of stretching exercises acutely reduced arterial stiffness. We hypothesized that this acute vascular response is due to regional mechanical stimulation of the peripheral arteries. To test this hypothesis, we examined the effect of a single bout of passive one leg stretching on arterial stiffness, comparing the stretched and the non-stretched leg in the same subject. METHODS: Twenty-five healthy young men (20.9 ± 0.3 years, 172.5 ± 1.4 cm, 64.1 ± 1.2 kg) volunteered for the study. Subjects underwent a passive calf stretching on one leg (six repetitions of 30-s static stretch with a 10-s recovery). Pulse wave velocity (PWV, an index of arterial stiffness), blood pressure (BP), and heart rate (HR) were measured before and immediately, 15, and 30 min after the stretching. RESULTS: Femoral-ankle PWV (faPWV) in the stretched leg was significantly decreased from baseline (835.0 ± 15.9 cm/s) to immediately (802.9 ± 16.8 cm/s, P < 0.01) and 15 min (810.5 ± 16.0 cm/s, P < 0.01) after the stretching, despite no changes in systolic and diastolic BP, or HR. However, faPWV in the non-stretched leg was not significantly altered at any time. Brachial-ankle PWV (baPWV) also showed similar responses with faPWV, but this response was not significant. Additionally, the passive stretching did not alter carotid-femoral PWV (cfPWV). CONCLUSIONS: These results suggest that mechanical stimulation to peripheral arteries as induced by static passive stretch may modulate arterial wall properties directly, rather than resulting in a systemic effect.

Acute Effect of Static Stretching Exercise on Arterial Stiffness in Healthy Young Adults.

OBJECTIVE: Habitual stretching exercise increases carotid arterial compliance, and acute stretching exercise increases arterial compliance in patients with myocardial infarction. However, it is not known whether this arterial adaptation is sustained after exercise. The aim of this study was to examine the effect of a single bout of stretching exercise on the time course of systemic, central, and peripheral arterial stiffness in healthy young subjects. DESIGN: Twenty-six healthy young men performed static stretching exercise involving the entire body (trunk, upper limb, and lower limb) for 40 mins. Pulse-wave velocity (PWV; an index of arterial stiffness), blood pressure, and heart rate were measured before and 0, 15, 30, and 60 mins after stretching exercise. RESULTS: Femoral-ankle PWV and brachial-ankle PWV were reduced relative to baseline 15 and 30 mins after acute stretching (P < 0.05); however, these arterial responses were not sustained for longer periods, and both PWV values returned to the baseline levels within 60 mins. By contrast, carotid-femoral PWV was unchanged. CONCLUSION: These results suggest that chronic and sufficient repetition of muscle stretch stimulation may result in chronic high arterial compliance, although a single bout of stretch exercise acutely affects arterial compliance.

Detection of Lawsonia intracellularis using immunomagnetic beads and ATP bioluminescence.

Lawsonia intracellularis is an obligate intracellular pathogenic bacterium that causes proliferative enteropathy in various animals. The detection of L. intracellularis in clinical and environmental samples is necessary for the diagnosis of infection and epidemiological investigations. For the detection of L. intracellularis in fecal samples, we have developed an immunological method using immunomagnetic separation and ATP bioluminescence. Magnetic beads were coated with an anti-Lawsonia surface antigen (LsaA) antibody in order to capture the L. intracellularis in fecal samples from infected rabbits and the bacteria captured by the immunomagnetic beads were assayed by means of ATP bioluminescence. Our results showed that L. intracelluraris was detected by immunomagnetic separation of bacteria-holding magnetic beads and ATP-based bioluminescence, suggesting that our methods could be useful for the diagnosis of proliferative enteropathy.

Enzyme-linked immunosorbent assay to detect Lawsonia intracellularis in rabbits with proliferative enteropathy.

Lawsonia intracellularis is an obligate intracellular pathogenic bacterium that causes proliferative enteropathy in domestic and experimental animals. Antiserum against synthetic peptides of the Lawsonia surface antigen (LsaA) well recognized L. intracellularis in infected ileum by immunohistochemistry. The synthetic peptides in LsaA showed strong reaction with serum from rabbits infected with L. intracellularis by enzyme-linked immunosorbent assay. These results suggest that ELISA used synthetic peptides in LsaA and anti-LsaA serum might be useful to diagnose for proliferative enteropathy.