The use of a cold pack during resistance exercises is effective for reducing intramuscular oxygenation and increasing myoelectric activity.

[Purpose] The purpose of this study was to determine the efficacy of using a cold pack while doing resistance exercises for enhancing muscle strength and muscle hypertrophy through decreased intramuscular oxygenation and/or increased myoelectric activity. [Participants and Methods] Twenty-four resistance-trained males (age: 26.4 ± 8.4 years, height: 169.3 ± 5.2 cm, body weight: 74.7 ± 8.8 kg) involved in this study. All the participants completed two experimental sessions in random order (cold pack resistance exercise and resistance exercise) with a 3-day interval. Four types of resistance exercises (4 sets × 8 repetitions with an 8-repetition maximum) targeting the right triceps brachii muscle were performed in both the experimental sessions. [Results] The percentage baseline oxyhemoglobin/myoglobin level during resistance exercise was significantly lower, the half-recovery time of muscle oxygenation in intervals between sets was significantly longer, and the myoelectric activity was significantly higher in the cold pack resistance exercise than in the resistance exercise session. [Conclusion] The results suggest that using a cold pack with resistance exercises is effective in inducing intramuscular deoxygenation and increasing myoelectric activity and may be useful for increasing muscle strength and inducing hypertrophy.

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.

Exercise-related fatigue affects joint-driven resistance: comparison of flexor and extensor.

[Purpose] Muscle fatigue can affect the inherent properties of muscles. It is important to know how muscle stiffness changes with muscle fatigue and the different effects of the initial and terminal stages of exercise. Therefore, we aimed to examine the effects of bicep and tricep contraction tasks that lead to fatigue on joint-driven resistance of the elbow joint. [Participants and Methods] Twenty-five healthy men were included. Joint-driven resistance of the elbow joint was measured before and after the muscle contraction task. The slope of the regression line of the angle torque at the time of passive movement was calculated as an elastic coefficient and the entire movable range, proximal range, and distal range were compared. [Results] Owing to the muscular contraction of the biceps and triceps, the elastic coefficient increased in the elbow joint during both flexion and extension. The rate of change in the elastic coefficient was lower during the tricep contraction task than during the bicep contraction task. For both tasks, the change in the elastic coefficient varied depending on the range of exercise. [Conclusion] Resistance exercise increased the driven resistance of the joint during passive movement, and this effect was greater during terminal exercises.

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.

Effects of skin surface cooling before exercise on lactate accumulation in cool environment.

PURPOSE: We assessed whether plasma lactate accumulation increased and the lactate threshold (LT) declined when the skin temperature was lowered by whole body skin surface cooling before exercise in cool, but not temperate, conditions, and whether the lowered LT was associated with sympathetic activation or lowered plasma volume (PV) by cold-induced diuresis. METHODS: Ten healthy subjects performed a graded maximal cycling exercise after pre-conditioning under three different conditions for 60 min. Ambient temperature (using an artificial climatic chamber) and water temperature in a water-perfusion suit controlled at 25 and 34 °C in temperate-neutral (Temp-Neut); 25 and 10 °C in temperate-cool (Temp-Cool); and at 10 and 10 °C in cool-cool (Cool-Cool) conditions, respectively. Esophageal (Tes) and skin temperatures were measured; plasma lactate ([Lac]p) and noradrenaline concentrations ([Norad]p), and relative change in PV (%ΔPV) were determined before and after pre-conditioning and during exercise, and LT was determined. RESULTS: After pre-conditioning, Tes was not different among trials, whereas the mean skin temperature was lower in Cool-Cool and Temp-Cool than in Temp-Neut (P < 0.001). During exercise, [Lac]p and [Norad]p were higher (P = 0.009 and P < 0.001, respectively) and LT was lower (P = 0.013) in Cool-Cool than in the other trials. The %ΔPV was not different among trials. LT was correlated with [Norad]p during exercise (R = 0.50, P = 0.005). CONCLUSIONS: Whole body skin surface cooling before exercise increases lactate accumulation and decreases LT with sympathetic activation when exercise is performed in a cool, but not in a temperate, environment.

Lower thermal sensation in normothermic and mildly hyperthermic older adults.

PURPOSE: It is important to know how thermal sensation is affected by normal aging under conditions that elevate core body temperature for the prevention of heat-related illness in older people. We assessed whether thermal sensation under conditions of normothermia (NT) and mild hyperthermia (HT) is lowered in older adults. METHODS: Seventeen younger (23 ±  3 years) and 12 older (71 ±  3 years) healthy men underwent measurements of the cold and warmth detection thresholds ( ± 0.1 °C/s) of their chest and forearm skin, and whole body warmth perception under NT (esophageal temperature, T es, ~36.5 °C) and HT (T es, ~37.3 °C; lower legs immersed in 42 °C water) conditions. RESULTS: Warmth detection threshold at the forearm was increased in older compared with younger participants under both NT (P = 0.006) and HT (P = 0.004) conditions. In contrast, cold detection threshold at the forearm was decreased in older compared with younger participants under NT (P = 0.001) but not HT (P = 0.16). Mild hyperthermia decreased cold detection threshold at forearm in younger participants (P = 0.001) only. There were no effects of age and condition on warmth and cold detection thresholds at chest. Whole body warmth perception increased during HT compared with NT in both groups (both, P < 0.001), and older participants had lower values than the younger group under NT (P = 0.001) and HT (P = 0.051). CONCLUSIONS: Skin warmth detection thresholds at forearm and whole body warmth perception under NT and HT and skin cold detection thresholds at forearm under NT deteriorated with aging.

Differences between cardiac memory T wave changes after idiopathic left ventricular tachycardia and ischemic T wave inversion induced by acute coronary syndrome.

BACKGROUND: Cardiac memory (CM) after idiopathic left ventricular tachycardia (ILVT) mimics ischemic T wave inversion (TWI) induced by acute coronary syndrome (ACS). We aimed to establish electrocardiography criteria for differentiating the CM from ischemic TWI. METHODS AND RESULTS: We evaluated 16 ILVT and 48 ACS patients. We identified TWI after ILVT in 9/16 patients (CM group), typically in leads II, III, aVF, aVR, and V4-6. The characteristics of CM were similar to TWI induced by ACS involving right coronary artery, but the CM group had more TWI in V4 and shorter QTc. The criteria of (1) positive T in aVL, (2) negative or isoelectric T in II, and (3) negative T in V4-6 or (4) QTc <430ms were 100% sensitive and 96% specific for the CM group. CONCLUSION: CM after ILVT can be differentiated in most cases from ischemic TWI by the distribution of TWI and the QTc.

Thermal sensation during mild hyperthermia is modulated by acute postural change in humans.

Thermal sensation represents the primary stimulus for behavioral and autonomic thermoregulation. We assessed whether the sensation of skin and core temperatures for the driving force of behavioral thermoregulation was modified by postural change from the supine (Sup) to sitting (Sit) during mild hyperthermia. Seventeen healthy young men underwent measurements of noticeable increase and decrease (±0.1 °C/s) of skin temperature (thresholds of warm and cold sensation on the skin, 6.25 cm2 of area) at the forearm and chest and of the whole-body warm sensation in the Sup and Sit during normothermia (NT; esophageal temperature (Tes), ∼36.6 °C) and mild hyperthermia (HT; Tes, ∼37.2 °C; lower legs immersion in 42 °C of water). The threshold for cold sensation on the skin at chest was lower during HT than NT in the Sit (P < 0.05) but not in Sup, and at the forearm was lower during HT than NT in the Sup and further in Sit (both, P < 0.05), with interactive effects of temperature (NT vs. HT) × posture (Sup vs. Sit) (chest, P = 0.08; forearm, P < 0.05). The threshold for warm sensation on the skin at both sites remained unchanged with changes in body posture or temperature. The whole-body warm sensation was higher during HT than NT in both postures and higher in the Sit than Sup during both NT and HT (all, P < 0.05). Thus, thermal sensation during mild hyperthermia is modulated by postural change from supine to sitting to sense lesser cold on the skin and more whole-body warmth.

Forced respiration during the deeper water immersion causes the greater inspiratory muscle fatigue in healthy young men.

[Purpose] The purpose of the present study was to evaluate the effect of water immersion at different water depths on respiratory function and the effect of inspiratory load breathing (ILB) during water immersion at different water depths on respiratory muscle strength evaluated by maximum inspiratory and expiratory pressures (PImax and PEmax, respectively). [Subjects] Eight healthy men participated randomly in three trials. [Methods] All sessions were conducted with the participants in a sitting position immersed in a water bath. We evaluated respiratory function, PImax and PEmax during submersion at three different levels of water depth (umbilicus; 4th-rib; or clavicle, CL) and after subsequent 15-min ILB. [Results] Decreases in vital capacity and expiratory reserve volume from baseline by water immersion were significantly greater in the CL trial than those in the other trials. In the CL trial, PImax was immediately reduced after ILB compared to that at baseline, and the reduction was significantly greater than those in the other trials. PEmax was not affected by ILB in any of the trials. [Conclusion] Forced respiration during deeper water immersion caused greater inspiratory muscle fatigue in healthy young men.

The effect of cognitive-motor dual-task training on cognitive function and plasma amyloid ß peptide 42/40 ratio in healthy elderly persons: a randomized controlled trial.

BACKGROUND: Physical activity reduces the incidence and progression of cognitive impairment. Cognitive-motor dual-task training, which requires dividing attention between cognitive tasks and exercise, may improve various cognitive domains; therefore, we examined the effect of dual-task training on the executive functions and on plasma amyloid ß peptide (Aß) 42/40 ratio, a potent biomarker of Alzheimer's disease, in healthy elderly people. METHODS: Twenty-seven sedentary elderly people participated in a 12-week randomized, controlled trial. The subjects assigned to the dual-task training (DT) group underwent a specific cognitive-motor dual-task training, and then the clinical outcomes, including cognitive functions by the Modified Mini-Mental State (3MS) examination and the Trail-Making Test (TMT), and the plasma Aß 42/40 ratio following the intervention were compared with those of the control single-task training (ST) group by unpaired t-test. RESULTS: Among 27 participants, 25 completed the study. The total scores in the 3MS examination as well as the muscular strength of quadriceps were equally improved in both groups after the training. The specific cognitive domains, "registration & recall", "attention", "verbal fluency & understanding", and "visuospatial skills" were significantly improved only in the DT group. Higher scores in "attention", "verbal fluency & understanding", and "similarities" were found in the DT group than in the ST group at post-intervention. The absolute changes in the total (8.5 ± 1.6 vs 2.4 ± 0.9, p = 0.004, 95 % confidence interval (CI) 0.75-3.39) and in the scores of "attention" (1.9 ± 0.5 vs -0.2 ± 0.4, p = 0.004, 95 % CI 2.25-9.98) were greater in the DT group than in the ST group. We found no changes in the TMT results in either group. Plasma Aß 42/40 ratio decreased in both groups following the training (ST group: 0.63 ± 0.13 to 0.16 ± 0.03, p = 0.001; DT group: 0.60 ± 0.12 to 0.25 ± 0.06, p = 0.044), although the pre- and post-intervention values were not different between the groups for either measure. CONCLUSIONS: Cognitive-motor dual-task training was more beneficial than single-task training alone in improving broader domains of cognitive functions of elderly persons, and the improvement was not directly due to modulating Aß metabolism.

A case of coronary artery compression syndrome resulting from peri-valvular regurgitation and long-standing atrial fibrillation.

A man in his 70s with a history of mitral valve replacement (MVR) and long-standing persistent atrial fibrillation (AF) presented with effort angina. Coronary angiography revealed severe stenosis of the left main coronary artery (LMCA). As it was an emergent case, PCI (percutaneous coronary intervention) was selected for treatment. Intravascular ultrasonography revealed no atherosclerotic lesions in the LMCA. The LMCA was effectively dilated by the drug-eluting stent. No elevation in intracardiac pressure was observed in cardiac catheterization after PCI. Computed tomography scan indicated potential compression of the LMCA by the surrounding structures. In cases of long-standing persistent AF and an enlarged atrium after MVR, the possibility of LMCA stenosis due to anatomical changes should be considered. Learning Objectives: ◾Peri-valvular regurgitation and long-standing persistent atrial fibrillation can potentially cause atrial enlargement.◾Coronary artery stenosis without atherosclerosis can occur due to compression from surrounding structures or shifting of the coronary artery.◾Stent therapy provides a temporary solution and coronary artery bypass grafting or switching should be considered if re-stenosis occurs.

A case of retractable helix lead auto-retraction: A possible cause of deep septal lead dislodgement.

This paper explains the phenomenon where the helix lead automatically retracts because of residual torque during deep septal pacing.

Reentrant ventricular outflow tract tachycardia arising from focal scar detected by delayed enhancement magnetic resonance imaging.

A 58-year-old man was referred to our emergency room with hemodynamically unstable sustained ventricular tachycardia (VT). The morphology of the VT exhibited a left bundle branch block and inferior axis deviation. He had no past history of cardiovascular disease. Echocardiography, cardiac catheterization, cardiac biopsy, gallium scintigram, myocardial scintigram, T1,T2-weighted magnetic resonance imaging (MRI), and gadolinium-enhanced cine MRI did not detect any structural heart disease or abnormal cardiac function. However, delayed-enhancement MRI (DE-MRI) detected a focal intramural scar within the septal ventricular outflow tract. An electrophysiological study revealed a sustained VT with several morphologies and the entrainment phenomenon. Radiofrequency catheter ablation to the site corresponding to the focal scar detected by DE-MRI successfully eliminated the VT.

Relationship between kyphosis and cough strength and respiratory function of community-dwelling elderly.

BACKGROUND: Kyphosis may reduce the force of coughing by affecting the factors related to cough peak flow (CPF). This study sought to compare cough strength and respiratory function between non-kyphotic and kyphotic elderly individuals and clarify the relationship between these factors. METHODS: The non-kyphotic group comprised 17 elderly individuals with a kyphosis index of less than 15.1, while the kyphotic group comprised 21 elderly individuals with a kyphosis index of 15.1 or higher. Cough strength, respiratory function, respiratory muscle strength, and maximum phonation time were measured, and comparison between two groups and correlation analysis between variables were performed. RESULTS: CPF, vital capacity, maximum expiratory pressure (PEmax), maximum inspiratory pressure (PImax), and chest expansion at the xiphoid process were significantly lower in the kyphotic group than in the non-kyphotic group. There were significant negative correlations between kyphosis index and CPF (r = -0.37, p < 0.05), PEmax (r = -0.45, p < 0.01), PImax (r = -0.44, p < 0.01) and chest expansion at the xiphoid process (r = -0.38, p < 0.05). CONCLUSIONS: Our results demonstrated that cough strength was significantly lower in the kyphotic compared to non-kyphotic individuals. Furthermore, cough strength decreased with increased severity of kyphosis.

Prevalence and characteristics of idiopathic right ventricular outflow tract arrhythmias associated with J-waves.

AIM: The arrhythmogenic relationship between the presence of J-waves during sinus rhythm and idiopathic ventricular tachycardia (VT) or pre-mature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) has not been reported. The aim of this study was to investigate the prevalence and characteristics of idiopathic RVOT-VT/PVCs associated with J-waves. METHODS AND RESULTS: The study enrolled 138 consecutive idiopathic RVOT-VT/PVC patients undergoing radiofrequency catheter ablation (RFCA) and 276 age- and gender-matched control subjects. The prevalence of J-waves was assessed in each cohort, and the clinical and electrophysiological data were compared between the RVOT-VT/PVC patients with J-waves (J-RVOT-VT/PVC group) and those without (non-J-RVOT-VT/PVC group). J-waves were more common among patients with idiopathic RVOT-VT/PVCs than among the matched control subjects (40 vs. 16% P < 0.001). The J-RVOT-VT/PVC group had a higher incidence of sustained VT (25 vs. 5%, P < 0.01), shorter VT cycle length (302 ± 57 vs. 351 ± 58 ms, P < 0.001), and more episodes of syncope (25 vs. 2%, P < 0.001) than did the non-J-RVOT-VT/PVC group. However, no patients demonstrated any ventricular fibrillation (VF) or cardiac sudden death in either group. CONCLUSIONS: There was a high prevalence of J-waves in the idiopathic RVOT-VT/PVC patients referred for RFCA. Although patients with idiopathic RVOT arrhythmias associated with J-waves might have a more enhanced arrhythmogenicity than those without J-waves, the significance of those J-waves was limited in terms of the prognosis and VF.

Clinical and electrophysiological difference between idiopathic right ventricular outflow tract arrhythmias and pulmonary artery arrhythmias.

INTRODUCTION: The precise incidence and characteristics of ventricular arrhythmias originating from the pulmonary artery have not been fully described. The purpose of this prospective study was to clarify these points. METHODS: Thirty-three consecutive patients with an idiopathic left bundle branch block and inferior-axis deviation type ventricular arrhythmia were included. All patients underwent detailed electroanatomical mapping (CARTO, Biosense-Webster, Diamond Bar, CA, USA) during sinus rhythm prior to the catheter ablation. The precise location of the catheter tip at the successful ablation site was confirmed by both electroanatomical mapping and contrast radiography. The clinical and electrophysiological data were compared between the right ventricular outflow tract (RVOT) arrhythmia patients (RVOT group) and PA arrhythmia patients (PA group). RESULTS: Eight patients (8/33 patients: 24.2%) had their ventricular arrhythmias successfully ablated within the PA. The local bipolar electrogram at the successful ablation sites in the PA group exhibited a significantly greater duration (P < 0.05) and lower amplitude (P < 0.05) than did those in the RVOT group (n = 19). In the PA group, all patients exhibited a multicomponent electrograms composed of a spiky potential and a dull potential, which might have consisted of near-field PA activation and a far-field ventricular activation, respectively, at the successful ablation site. Direct ablation to the spiky electrogram was able to eliminate the arrhythmias in all the PA group patients. CONCLUSIONS: PA arrhythmias may be more common than previously recognized. Careful mapping and interpretation of low amplitude and multicomponent electrograms are important for recognizing ventricular arrhythmias originating from the PA.

Distribution of successful ablation sites of idiopathic right ventricular outflow tract tachycardia.

BACKGROUND: There are few studies evaluating the distribution of successful ablation sites of idiopathic right ventricular outflow tract (RVOT) arrhythmias using a three-dimensional electroanatomical mapping system. This study aims to clarify the favorite site of idiopathic RVOT arrhythmias through electroanatomical voltage mapping using the CARTO system (Biosense Webster, Diamond Bar, CA, USA). METHODS: A consecutive series of 72 patients (mean age 43.6 +/- 16.2 years, 32 males) who underwent radiofrequency catheter ablation (RFCA) for a total of 82 morphologies of idiopathic RVOT arrhythmias were studied. Detailed three-dimensional electroanatomical voltage maps of the RVOT were obtained using the CARTO system prior to the RFCA during sinus rhythm. The voltage on bipolar electrogram was defined as follows: amplitude < 0.5 mV as "low-voltage zone," amplitude between 0.5 and 1.5 mV as "transitional-voltage zone," and amplitude >1.5 mV as "high-voltage zone." Successful ablation sites were electroanatomically classified into each voltage zone. RESULTS: Successful ablation was acquired in 63 patients and 71 RVOT arrhythmias (63/72 patients: 87.5%, 71/82 RVOT arrhythmias: 86.5%). In the successful group, three arrhythmias (4.2%) were classified in the low-voltage zone, 63 arrhythmias (88.7%) in the transitional-voltage zone, and five arrhythmias (7.0%) in the high-voltage zone. CONCLUSIONS: This study indicates that the vast majority of successful ablation sites for idiopathic RVOT arrhythmias are located in the transitional-voltage zone. Mapping of the transitional-voltage zone may be an important landmark of RFCA for RVOT arrhythmia.

Idiopathic ventricular arrhythmias arising from the posterior septum of tricuspid and mitral annuli: comparison of electrocardiographic characteristics and outcomes of catheter ablation.

PURPOSE: Ventricular arrhythmia (VA) arising from the tricuspid annulus in the posterior septum (PS) (TAPS-VA) has similar electrocardiographic characteristics as VA arising from the mitral annulus in the PS (MAPS-VA) because the two locations are adjacent. We examined the electrocardiographic characteristics that differentiate MAPS-VA from TAPS-VA and the efficacy of catheter ablation. METHODS: We studied 13 patients whose VAs were successfully ablated in the TAPS (n = 7) and MAPS (n = 6). RESULTS: QRS morphologies of both groups were characterized by left and right bundle block morphologies in lead V1, superior axis deviation, and precordial transition at ≤ lead V3 in nine patients. Compared with TAPS-VA, MAPS-VA had (1) R < S wave in lead II, (2) precordial transition in lead V2, (3) s-wave in lead V6, and (4) slurred initial part of the QRS complex in the precordial leads, e.g., [4a] pseudo delta wave ≥ 34 ms, [4b] intrinsicoid deflection time ≥ 85 ms, and [4c] maximum deflection index ≥ 0.55. Patients who met ≥ 2 of (1)-(3) and any of [4a]-[4c] could be classified as having MAPS-VA, with a sensitivity and specificity of 100%. VA recurred in one patient in the TAPS group during the median follow-up of 7 (interquartile range 6 to 15.5) months. CONCLUSIONS: VA arising from the PS has superior axis deviation, and left and right bundle block morphologies with relatively early precordial transition. MAPS-VA can be differentiated from TAPS-VA based on electrocardiographic characteristics. This study provides useful information for treatment involving catheter ablation for VA arising from the PS.