Effect of Expiratory Muscle Fatigue on the Respiratory Response during Exercise

[Purpose] The aim of this study was to reveal the effect of expiratory muscle fatigue (EMF) on respiratory response under two different exercise conditions: exercise (EX) with EMF (EMF-EX) and control EX without EMF (CON-EX). [Methods] Nine healthy adult men performed cycle exercise with a ramp load, and a spirometer was used to measure forced vital capacity (FVC), forced expiratory volume in one second, percent of forced expiratory volume, maximal expiratory mouth pressure, and maximal inspiratory mouth pressure (PI_max) to evaluate respiratory functions immediately and at 15 and 30 min after exercise. To assess the respiratory response during exercise, an exhaled gas analyzer was used to measure minute ventilation (V_E), respiratory frequency (f), tidal volume (V_T), oxygen uptake, and carbon dioxide output. In addition, the Borg Scale was used to evaluate dyspnea, while electrocardiography was used to measure heart rate. [Results] The results showed that compared with the CON-EX condition, no change in V_E, an increase in f, or a decrease in V_T was observed under the medium-intensity EMF-EX condition, while high-intensity exercise reduced V_E and f without changing V_T. [Conclusion] These results suggest that during medium-intensity exercise, EMF modulates the respiratory response by inducing shallow and fast breathing to increase ventilation volume.Key words: Expiratory muscle fatigue, Maximal mouth pressure, Respiratory response     

Influence of neck pain on cervical movement in the sagittal plane during smartphone use

[Purpose] Smartphone use reportedly changes posture. However, how neck posture is altered in smartphone users with neck pain is unknown. This study examined changes in the posture of young adults with and without mild neck pain (MNP) when using a smartphone. [Subjects] Thirteen control subjects and 14 subjects with MNP who used smartphones were recruited. [Methods] The upper cervical (UC) and lower cervical (LC) angles in the sagittal plane were measured using an ultrasound-based motion analysis system while the seated subjects used a smartphone for 5 min. [Results] During smartphone use, the MNP group exhibited greater UC and LC flexion angles than the control group. [Conclusion] These findings suggest that young adults with MNP are more careful and more frequently utilize a neutral neck posture than young adults without MNP when using a smartphone while sitting.Key words: Smartphone, Cervical flexion, Young adult     

Effect of Wrist Joint Restriction on Forearm and Shoulder Movement during Upper Extremity Functional Activities

[Purpose] This study measured %isolation and investigated whether it shows a difference between the presence and absence of wrist joint restriction, as well as changes in muscle activity patterns. [Methods] Twenty subjects performed upper extremity functional movement in the Manual Function Test (MFT) with and without wrist restriction, and the muscle activities of the trapezius, middle deltoid, biceps brachii, triceps brachii, extensor carpi radialis, and flexor carpi radialis were recorded. When there were differences in muscle activation, %isolation was implemented and the changes in the muscle activity patterns were noted. [Results] In the grasping and pinching tasks, there was a significant increase in %isolation of the upper trapezius and a significant decrease in %isolation of the extensor carpi radialis. Carrying a cube task, %isolation of the upper trapezius and middle deltoid significantly increased, whereas %isolation of the triceps brachii and extensor carpi radialis significantly decreased. In the pegboard task, the %isolation values of the extensor carpi radialis and flexor carpi radialis significantly decreased. [Conclusion] The data of this study should be useful for therapists, who can employ the information as material for the education and treatment of patients with wrist joint restriction. Therapists may thus look for ways to improve the quality of mobility by predicting the complement mobility depending on the activity performed and then determine whether to facilitate or restrict mobility.Key words: Functional upper extremity activity, %isolation, Wrist joint restriction     

Experimental Joint Immobilization and Remobilization in the Rats

[Purpose] The purpose of our study was to clarify temporal effects on restrictions to range of motion and the histopathological changes of joint components after joint immobilization in a rat knee-contracture model. [Subjects] Fifty-four male Wistar rats were randomly divided into two groups: a fixation group, and a control group. [Methods] In the fixation group, unilateral knee joints were immobilized at full flexion using a plaster cast for 4 weeks. At four weeks the animals were randomly divided into six subgroups, corresponding to the time of examination after cast removal: 0, 4, 8, 16, 24, and 32 weeks. For comparison, control group animals of corresponding age were also examined. [Results] Although movement restrictions of the knee joint had completely recovered 6 weeks after the cast removal, cartilage and synovial membrane structures did not completely recover. [Conclusion] These findings have not previously been reported, and as they form an addition to the fundamental scientific foundations of physical therapy, further research must examine these findings from a variety of perspectives.Key words: Contracture, Articular cartilage, Synovial membrane     

四肢关节功能牵引法—附器械介绍及临床应用1424例分析

本文介绍了适用于改善四肢关节活动度的关节功能牵引方法及一套专用的简易器械,从而为关节活动度的恢复提出了一项新的方法。作者通过此法的1424例临床应用,观察了对各种体创伤的疗效。在拇外展牵引病例的自身对比中证明其疗效明显地高于传统的由主动、被动运动和按摩构成的锻炼方法。从纤维组织的力学特性出发探讨了关节功能牵引作用特点,从实际疗效总结中分析了影响疗效的因素,指出关节功能牵引有疗效较好,不易引起新的损伤,痛苦少及操作方便等优点。     

Effect of Assistive Device for Neck Retraction (ANR) on Neck Muscles during Neck Retraction Exercise

[Purpose] The purpose of present study was to develop an exercise device for assisting neck retraction exercise and to investigate its effectiveness. [Subjects] Fifteen male subjects were recruited. [Methods] The subjects performed the neck retraction exercises with and without assistive device for neck retraction (ANR). EMG activities of the lower cervical erector spinae (LCE), and sternocleidomatoid (SCM) muscles were recorded. [Results] The ANR condition significantly increased LCE activation compared to the control condition. The ANR condition significantly decreased SCM activation compared to the control condition. [Conclusion] We suggest that the ANR condition will help the efficacy of the neck retraction exercise.Key words: Electromyography, Forward head posture, Neck retraction exercise     

Effects of kinesio taping on lumbopelvic-hip complex kinematics during forward bending

[Purpose] The aim of this study was to investigate the effect of kinesio taping (KT) on the kinematics of the lumbo-pelvic-hip complex during forward bending by individuals with reduced hamstring extensibility. [Subjects] Eighteen males with reduced hamstring extensibility were randomly assigned to one of two groups:, the hamstring KT group (n=9), or the sham KT group (n=9). [Methods] The kinematics of the lumbopelvic-hip complex during lumbar forward bending was measured using a motion capture system before and after applying KT. [Results] The angle of lumbar flexion during late lumbar forward bending increased significantly post-KT compared to pre-KT measurements in the hamstring KT group. [Conclusion] These findings suggest that KT does not directly affect an individual’s movement during lumbar forward bending.Key words: Kinematics, Kinesio taping, Lumbar forward bending     

The effects of backrest thickness on the shoulder muscle load during wheelchair propulsion

[Purpose] This study investigated the optimal thickness of the wheelchair backrest for lumbar load and increased comfort. [Subjects] Fifteen healthy people participated. [Methods] The study examined three randomized backrest conditions: no pad; a 3-cm-thick lumbar pad; and a 6-cm-thick lumbar pad. The location of the lumbar pad was standardized at the mid-lumbar level (L3). Participants were instructed to propel the wheelchair using only the handrims. [Results] Activation of the anterior deltoid, upper trapezius, and biceps brachii muscles was significantly reduced when the participants used the 3-cm pad compared to no pad, while it was significantly increased in the anterior deltoid, upper trapezius, posterior deltoid, and biceps brachii when the participants used the 6-cm pad compared to the 3-cm pad. Muscle activation did not differ significantly between the no pad and the 6-cm lumbar pad conditions. [Conclusion] A lumbar pad decreased the activation of the upper extremity muscles. We believe that padding of the appropriate thickness will lead to effective muscle activation while propelling a wheelchair and decrease the risk of musculoskeletal disease.Key words: Electromyography, Lumbar pad, Wheelchair     

Histopathological Changes in the Periphery of the Sciatic Nerve of Rats after Knee Joint Immobilization

[Purpose] This study was performed to investigate the histological changes that occur in the periphery of the sciatic nerve in rats undergoing knee immobilization. [Subjects and Methods] 29 male 9-week-old Wistar rats were divided randomly into a control group (C group, n = 7) and an immobilized group (I group, n = 22). The animals in the I group had the left knee joint immobilized in maximal flexion with plaster casts for two weeks. After the experimental period, we obtained cross-sections of tissues from the center of the left thigh, and the periphery of the sciatic nerve was observed under an optical microscope after hematoxylin-eosin staining. [Results] In contrast to the rats of C group, the rats in I group showed adherence between the bundle of nerve fibers and perineurium, as well as thickening of the perineurium. These histological changes were statistically significant. [Conclusions] Immobilization of the knee joints of rats resulted in characteristic histological changes in the connective tissue around the sciatic nerve.Key words: Contracture, Sciatic nerve, Perineurium     

The Influence of Lumbar Joint Mobilization on Joint Position Sense in Normal Adults

[Purpose] The purpose of this study was to determine the effects of lumbar joint mobilization on the joint position sense (JPS) of normal adults. [Subjects] A total of 30 normal adults were divided into an experimental group (n = 15) and a control group (n = 15). [Methods] The experimental group received lumbar joint mobilization and massage, and the control group received massage only. Both the experimental and control groups were evaluated for joint position error (JPE) by using a digital dual inclinometer before and after the experiment. [Results] In the before and after comparison for the experimental group, statistically significant differences were found in flexion, extension, left lateral flexion, and right lateral flexion. There was no statistically significant difference in the before and after comparison for the control group. [Conclusion] Because lumbar joint mobilization can reduce JPE and improve JPS, its use in the treatment of patients with lumbar problems is recommended.Key words: Gong’s mobilization, Joint position sense, Joint position error     

Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces

Background:

Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse''s movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject''s postural control.

Objective:

To test whether different types of surfaces promote changes in the amplitude (ACOP) and velocity (VCOP) of the center of pressure (COP) displacement during the rider''s contact with the saddle on the horse''s back.

Method:

Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat.

Results:

ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019). The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006). The VCOP did not differ between the surfaces.

Conclusion:

Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.     

Effect of a Dynamic Air Cushion on the Development of Leg Edema during Wheelchair Sitting

[Purpose] To clarify how a novel dynamic cushion affects the leg edema evoked by wheelchair sitting, we measured the changes in leg volume induced during wheelchair sitting with the dynamic air cushion or a static cushion. [Subjects and Methods] Nine healthy male subjects participated in this study. Leg edema during wheelchair sitting was evaluated with strain gauge plethysmography (the gauge was placed around the middle portion of the lower thigh). Following a period of rest, each subject was asked to sit on a wheelchair containing the dynamic cushion for 15 min. Then, the protocol was repeated with a static cushion. The angles of the knee and ankle joints were set to 90 degrees, and no footrests were used. [Results] The change in leg volume observed during sitting on the dynamic cushion (0.00 ± 0.03 mL/100 mL) was smaller than that observed during sitting on the static cushion (0.02 ± 0.02 mL/100 mL). [Conclusion] These results suggested that the dynamic cushion relieved leg edema during wheelchair sitting.Key words: Wheelchair cushion, Leg volume, Healthy human     

The influence of accuracy constraints on EMG and kinetic variables during gait initiation

[Purpose] This study investigated the effects of accuracy constraints (targets) placed on the stepping-limb heel-strike (HS) on the electromyogram (EMG) and ground reaction forces (GRFs) during gait initiation. [Subjects and Methods] Twenty healthy subjects (29.2 ± 2.9 years) were asked to begin walking or stepping over a 10-cm-high obstacle at a fast speed. A 3-cm-diameter target was placed on the ground to dictate the position and accuracy of the stepping-limb HS. [Results] The results showed that the initiation velocity increase in the no-target conditions was due to modulation of the stance- and stepping-limb GRFs and a corresponding increase in the tibialis anterior (TA) activities of both limbs before stepping-limb toe-off. This was achieved by significantly increasing the stepping- and stance-limb TAEMG1 (determined between the onset of movement and time to peak anteroposterior (A-P) GRF of the stepping- and stance- limb) for the no-target conditions. It seems, therefore, that TAEMG1 and the slope to stepping-limb peak A-P GRF contributed to the intended velocity of initiation. [Conclusion] These data indicate that gait initiation and/or stepping over an obstacle may prove to be tasks by which motor control can be measured. The present study provides insight into the working mechanisms of the stepping and stance limbs and shows a clear need to further investigate whether the intact or affected limb should be used to initiate gait during rehabilitation and prosthetic training.Key words: Electromyogram, Gait initiation, Ground reaction forces     

Difference in Physiological Components of VO2 Max During Incremental and Constant Exercise Protocols for the Cardiopulmonary Exercise Test

[Purpose] VO₂ is expressed as the product of cardiac output and O₂ extraction by the Fick equation. During the incremental exercise test and constant high-intensity exercise test, VO₂ results in the attainment of maximal O₂ uptake at exhaustion. However, the differences in the physiological components, cardiac output and muscle O₂ extraction, have not been fully elucidated. We tested the hypothesis that constant exercise would result in higher O₂ extraction than incremental exercise at exhaustion. [Subjects] Twenty-five subjects performed incremental exercise and constant exercise at 80% of their peak work rate. [Methods] Ventilatory, cardiovascular, and muscle oxygenation responses were measured using a gas analyzer, Finapres, and near-infrared spectroscopy, respectively. [Results] VO₂ was not significantly different between the incremental exercise and constant exercise. However, cardiac output and muscle O₂ saturation were significantly lower for the constant exercise than the incremental exercise at the end of exercise. [Conclusion] These findings indicate that if both tests produce a similar VO₂ value, the VO₂ in incremental exercise would have a higher ratio of cardiac output than constant exercise, and VO₂ in constant exercise would have a higher ratio of O₂ extraction than incremental exercise at the end of exercise.Key words: Cardiopulmonary exercise test, Fick equation, Near-infrared spectroscopy     

Activities of the Vastus Lateralis and Vastus Medialis Oblique Muscles during Squats on Different Surfaces

[Purpose] The purpose of the present study was to examine the effects of squat exercises performed on different surfaces on the activity of the quadriceps femoris muscle in order to provide information on support surfaces for effective squat exercises. [Subjects and Method] Fourteen healthy subjects performed squat exercises for five seconds each on three different support surfaces: hard plates, foam, and rubber air discs. Their performance was measured using electromyography. As the subjects performed the squat exercises on each surface, data on the activity of the vastus medialis oblique and the vastus lateralis, and the vastus medials oblique/vastus lateralis ratio, were collected. [Results] The activity of the vastus medialis oblique and the vastus medialis oblique/vastus lateralis ratio were found to be statistically significantly higher on rubber air discs than when the squats were performed on hard plates or foam. [Conclusion] To activate the vastus medialis obilique, and to enhance the vastus medialis oblique/vastus lateralis ratio, unstable surfaces that are highly unstable should be selected.Key words: Support surfaces, Vastus medialis obilique, Vastus lateralis     

Cangrelor dose titration using platelet function testing during cerebrovascular stent placement

BackgroundOptimal antiplatelet inhibition is vital during cerebrovascular stenting procedures, yet no standardized recommendation exists for antithrombotic therapy in these scenarios. Cangrelor is an intravenous P2Y12 inhibitor with a favorable pharmacokinetic profile for use during neuroendovascular stenting.MethodsA retrospective review of all neuroendovascular patients who underwent stenting between 1 January 2019 and 22 March 2020 and were treated with cangrelor was conducted. Thirty-seven patients met inclusion criteria.ResultsAll patients were administered a bolus of 5 mcg/kg of cangrelor followed by a maintenance infusion. Antiplatelet effects of cangrelor were monitored using platelet reactivity units (PRU). Based on the initial PRU, seven patients’ doses were adjusted with subsequent PRUs in or near the goal range of 50–150. One patient experienced an acute intraprocedural occlusion likely related to a subtherapeutic PRU which subsequently resolved with cangrelor dose adjustment and intra-arterial tirofiban administration, and one patient experienced a post-procedure stent occlusion which required a thrombectomy and intra-arterial tirofiban administration. No hemorrhagic complications occurred.DiscussionCangrelor utilization during neuroendovascular stenting with maintenance doses of <2 mcg/kg/min with dose adjustments based on platelet function testing has not been previously described. Cangrelor presents many advantages compared to standard therapy in patients undergoing stent placement related to its pharmacokinetic profile, rapid onset of action, ease of transition to oral P2Y₁₂ antiplatelet agents, and measurability.ConclusionCangrelor is a promising alternative to currently available therapies, especially in patients with a high hemorrhagic risk.     

Contribution of hip and knee muscles to lateral knee stability during gait

[Purpose] Lateral knee instability is frequently observed in patients with knee injury or risk factors associated with knee osteoarthritis. Physical exercises can strengthen muscles that stabilize the knee joint. The purpose of this study was to define the contribution of the knee and hip muscles to lateral knee stability by comparing the muscle forces, as assessed by musculoskeletal simulation using one or two degrees-of-freedom (1-DOF and 2-DOF) knee models. [Participants and Methods] We evaluated the normal gait of 15 healthy subjects. We conducted a three-dimensional gait analysis using a motion analysis system and a force plate. We considered a muscle as a lateral knee stabilizer when the calculated muscle force was greater with the 2-DOF model than with the 1-DOF model. [Results] During early and late stance, the muscle forces of the lateral knee and hip joint increased in the 2-DOF model as opposed to in the 1-DOF model. In contrast, the forces of the medial knee muscles decreased. Furthermore, hip muscle forces increased during the late stance. [Conclusion] Our results show that the lateral knee and hip muscles contribute to lateral knee stability. Thus, exercises to strengthen these muscles could improve lateral knee stability.Key words: Lateral knee stability, Musculoskeletal model, Gait analysis     

The Effects of Elbow Joint Angle Change on the Elbow Flexor Muscle Activation in Pulley with Weight Exercise

[Purpose] This research investigated the effect of angular variation of flexion of the elbow joint on the muscle activation of elbow flexor muscles. [Subjects] The research subjects were 24 male college students with a dominant right hand who had no surgical or neurological disorders and gave their prior written consent to participation with full knowledge of the method and purpose of this study. [Methods] The subjects'' shoulder joints stayed in the resting position, and the elbow joint was positioned at angles of 55°, 70°, and 90°. The angle between the pulley with weights and forearm stayed at 90°. Surface electromyography was used to measure muscle activities. Three measurements were made at each elbow angle, and every time the angle changed, two minutes rest was given. [Result] The muscle activities of the elbow flexors showed significant changes with change in the elbow joint angle, except for the biceps brachii activities between the angles of 55° and 70° of elbow flexion. The muscle activities of the biceps brachii and brachioradialis showed angle-related changes in the order of 55°, which showed the biggest value, followed by 70° and 90°. [Conclusion] In order to improve muscle strength of the elbow flexor using a pulley system, it seems more effective to have a 90° angle between the pulley with weights and the forearm when the muscle is stretched to a length 20% greater than its resting position.Key words: Pulley with weight exercise, Joint angle, Muscle activation     

Effects on ROM and joint position sense of the neck of two different interventions

[Purpose] The purpose of this study was to evaluate whether neuromuscular joint facilitation (NJF) training is superior to NJF distal resistance training at improving the ROM and proprioceptive acuity of the neck. [Subjects] 10 healthy subjects (8 males, 2 females) participated in this study. [Methods] The participants were allocated to three groups: 10 in the control group, 10 in the NJF distal resistance training group, and 10 in the NJF training group. A miniature wireless motion recorder was used to record the maximum cervical range of motion and joint position error (JPE) before and after the interventions. The three interventions were tested on different days. [Results] No difference of ROM was observed among the three groups. A significant pre- to post-intervention decrease in JPE in extension was identified in the NJF group. No other significant differences were observed among the three groups. [Conclusion] The NJF training conferred remarkable benefits on the cervical JPE of healthy people. This result suggests that the best way to improve proprioceptive acuity is intervention together with proximal resistance training, such as NJF training.Key words: Neck, Joint position sense, Neuromuscular joint facilitation (NJF)     

Trunk Control Ability after Minimally Invasive Lumbar Fusion Surgery during the Early Postoperative Phase

[Purpose] Lumbar fusion has been used for spinal disorders when conservative treatment fails. The minimally invasive approach causes minimal damage to the back muscles and shortens the postoperative recovery time. However, evidence regarding functional recovery in patients after minimally invasive lumbar spinal fusion is limited. The purpose of this study was to investigate how trunk control ability is affected after minimally invasive lumbar fusion surgery during the early postoperative phase. [Subjects and Methods] Sixteen patients and 16 age- and sex-matched healthy participants were recruited. Participants were asked to perform a maximum forward reaching task and were evaluated 1 day before and again 1 month after the lumbar fusion surgery. Center of pressure (COP) displacement, back muscle strength, and scores for the Visual Analog Scale, and Chinese version of the modified Oswestry Disability Index (ODI) were recorded. [Results] The healthy control group exhibited more favorable outcomes than the patient group both before and after surgery in back strength, reaching distance, reaching velocity, and COP displacement. The patient group improved significantly after surgery in all clinical outcome measurements. However, reaching distance decreased, and the reaching velocity as well as COP displacement did not differ before and after surgery. [Conclusion] The LBP patients with lumbar fusion surgery showed improvement in pain intensity 1 month after surgery but no improvement in trunk control during forward reaching. The results provide evidence that the back muscle strength was not fully recovered in patients 1 month after surgery and limited their ability to move their trunk forward.Key words: Biomechanics, Postural balance, Low back pain