Short-term Effects of Transcranial Near-Infrared Photobiomodulation on Motor Performance in Healthy Human Subjects: An Experimental SingleBlind Randomized Clinical Trial.

Introduction: Transcranial near-infrared photobiomodulation (NIR-PBM) is a new noninvasive procedure which transcranially applies a near-infrared wavelength to the scalp with a laser or a light-emitting diode (LED) source. Improvement in the neurological or psychological symptoms has been reported following light irradiation. However, to our knowledge, there is no study to investigate the effects of transcranial NIR-PBM on motor performance directly. Therefore, the objective of this study was to investigate the short-term effects of transcranial NIR-PBM on motor performance in healthy human subjects. Methods: In this experimental single-blind randomized clinical trial study, 56 right-handed healthy participants, whose ages ranged from 18 to 30, were randomly assigned to (1) Real transcranial NIR-PBMC3 group (n=14), (2) Sham transcranial NIR-PBMC3 group (n=14), (3) Real transcranial NIR-PBMC4 group (n=14), and (4) Sham transcranial NIR-PBMC4 group (n=14). We applied the 808 nm laser with irradiation energy density of 60 J/cm2 and power density of 200 mw/cm2 to the C3 or C4 points of the scalp. The number of finger taps as an indicator of motor performance was assessed by the finger-tapping test (FTT) before and after irradiation of transcranial NIR-PBM on the corresponding points of the scalp for 5 minutes. Results: The results showed that the number of finger taps in both right and left hands following the use of transcranial NIR-PBM in the real transcranial NIR-PBMC3 group significantly increased (P<0.05). Conclusion: We concluded that using transcranial NIR-PBM with a laser source on C3 point of the motor cortex in right-handed healthy people can increase the number of finger taps in both hands as an indicator of motor performance improvement.

Myoelectric Activity of Individual Lumbar Erector Spinae Muscles Variation by Differing Seat Pan Depth.

BACKGROUND: The chair influences the position of the user in relation to his or her devices. Prolonged static sitting is a frequently mentioned risk factor for low back pain. Seat design, thus, plays an important role in the study of human sitting. Quantitative information is needed on what happens to body when one sits in chairs with different seat depth. OBJECTIVE: To determine the myoelectric activity (EMG) of individual lumbar erector spinae muscles after sitting in chairs with different seat pan depth. METHODS: EMG recordings were taken using surface electrodes placed on the lumbar erector spine muscles of 25 normal, volunteer subjects. EMG recordings for muscle activity were made while the study participants were in a comfortable position and performed the required tasks. The experiments investigated with 3 seat depths according to the 5th, 50th and 95th percentiles of the buttock popliteal length. The recorded EMG data were normalized to the maximal voluntary contraction. The mean EMG recording was calculated for each of the 3 chairs tested. A mixed model was used to assess the differences among the situations. RESULTS: A significant (p<0.05) difference was observed between the mean EMG recordings for the 3 tested seat pan depths. EMG activity was higher in seats with the 5th and 95th percentiles compared with that for the seat with 50th percentile of buttock popliteal length depth. CONCLUSION: The seat pan depth used during a comfortable position has a significant effect on the level of myoelectric activity in the lumbar erector spinal muscles. The finding of this study may contribute to our understanding of the biomechanics of sitting.

Vibration settling time of the gastrocnemius remains constant during an exhaustive run in rear foot strike runners.

In this study, vibrations of human gastrocnemius during an exhaustive run protocol are considered for analysis. Previous studies have shown increased vibration intensity and damping coefficient within the soft tissue with fatigue. The question of this study was to investigate if the vibration settling time remains constant during a prolonged running. Eleven semi-professional middle/long distance runners ran to exhaustion on a treadmill with their preferred constant speed (4.29 ±â€¯0.33 m/s) for 3873 ±â€¯1147 m. Vibration of the gastrocnemius lateralis, electrical activity of the tibialis anterior and the gastrocnemius medialis along with ground reaction force (GRF) were recorded. The results demonstrated significant increase in impact peak and loading rate, and the frequency content of the impact, with no significant change in active peak of the vertical GRF. Fatigue resulted in increased vibration intensity, damping coefficient, and energy dissipation of vibration with no change in vibration settling time. Furthermore, peak acceleration significantly linearly (R = 0.59) increased as a function of running time. The mean frequency of muscle activity of the gastrocnemius medialis and the intensity of muscle activity in TA significantly decreased. The results suggest that constant vibration settling time might either be an objective for muscle tuning which is more pronounced in fatigued state or a passive by-product of muscle function in running. Further studies are needed to address this point.

Effects of External Perturbations on Anticipatory and Compensatory Postural Adjustments in Patients with Multiple Sclerosis and a Fall History.

BACKGROUND: Although previous studies have investigated postural adjustment mechanisms in patients with multiple sclerosis (MS), it seems that no study has yet investigated the relationship between anticipatory and compensatory postural adjustments (APAs and CPAs, respectively) and falls. METHODS: Seventeen MS fallers, 17 MS nonfallers, and 15 controls were exposed to a series of expected and unexpected backward pull perturbations applied at the trunk level. The electrical activity of 12 leg and trunk muscles as well as center of pressure displacement were recorded. RESULTS: The MS fallers had delayed muscle activity onsets compared with MS nonfallers and controls. In addition, a significantly lower level of muscle activity during APAs was detected in MS fallers compared with controls. Moreover, in the unexpected condition of perturbation, significantly smaller CPA was observed in MS fallers compared with controls. Both groups of patients with MS required more time to stabilize their center of pressure after both types of perturbations compared with controls. CONCLUSIONS: The inability to produce efficient APAs and CPAs during perturbations may explain the high rates of postural instability and falls in patients with MS. Findings from this study provide a background for the development of perturbation-based training programs aimed at balance improvement and fall prevention by restoring mechanisms underlying balance impairments.

Effects of McGill stabilization exercises and conventional physiotherapy on pain, functional disability and active back range of motion in patients with chronic non-specific low back pain.

[Purpose] The aim of this study was to compare the effects of "McGill stabilization exercises" and "conventional physiotherapy" on pain, functional disability and active back flexion and extension range of motion in patients with chronic non-specific low back pain. [Subjects and Methods] Thirty four patients with chronic non-specific low back pain were randomly assigned to McGill stabilization exercises group (n=17) and conventional physiotherapy group (n=17). In both groups, patients performed the corresponding exercises for six weeks. The visual analog scale (VAS), Quebec Low Back Pain Disability Scale Questionnaire and inclinometer were used to measure pain, functional disability, and active back flexion and extension range of motion, respectively. [Results] Statistically significant improvements were observed in pain, functional disability, and active back extension range of motion in McGill stabilization exercises group. However, active back flexion range of motion was the only clinical symptom that statistically increased in patients who performed conventional physiotherapy. There was no significant difference between the clinical characteristics while compared these two groups of patients. [Conclusion] The results of this study indicated that McGill stabilization exercises and conventional physiotherapy provided approximately similar improvement in pain, functional disability, and active back range of motion in patients with chronic non-specific low back pain. However, it appears that McGill stabilization exercises provide an additional benefit to patients with chronic non-specific low back, especially in pain and functional disability improvement.

Electrophysiological assessment of piano players' back extensor muscles on a regular piano bench and chair with back rest.

[Purpose] Sitting position is the dominant position for a professional pianist. There are many static and dynamic forces which affect musculoskeletal system during sitting. In prolonged sitting, these forces are harmful. The aim of this study was to compare pianists' back extensor muscles activity during playing piano while sitting on a regular piano bench and a chair with back rest. [Subjects and Methods] Ten professional piano players (mean age 25.4 ± 5.28, 60% male, 40% female) performed similar tasks for 5 hours in two sessions: one session sitting on a regular piano bench and the other sitting on a chair with back rest. In each session, muscular activity was assessed in 3 ways: 1) recording surface electromyography of the back-extensor muscles at the beginning and end of each session, 2) isometric back extension test, and 3) musculoskeletal discomfort questionnaire. [Results] There were significantly lesser muscular activity, more ability to perform isometric back extension and better personal comfort while sitting on a chair with back rest. [Conclusion] Decreased muscular activity and perhaps fatigue during prolonged piano playing on a chair with back rest may reduce acquired musculoskeletal disorders amongst professional pianists.

Hip joint torques in type II diabetes with and without neuropathy.

BACKGROUND: Patients with diabetes and peripheral neuropathy demonstrate significantly reduced peak torques at the peripheral joints. OBJECTIVES: The aim of this study was to assess isometric and concentric peak torques of the hip joint in people with type II diabetes with and without peripheral neuropathy in comparison with healthy participants. METHODS: 27 patients with type II diabetes including 15 patients without peripheral neuropathy, 12 patients with diabetes and peripheral neuropathy and 15 healthy people participated. Isometric and concentric peak torques of hip flexion, extension, adduction and abduction of the non-dominant leg were measured by motorized dynamometer. RESULTS: Peak and average peak concentric torques of the hip extension and abduction in patients with diabetes and peripheral neuropathy were lower than those patients with diabetes and control group. Angle of extension peak torque was significantly greater in patients with diabetes and peripheral neuropathy compared with other groups. Angle of flexion peak torque was lower in the patients with diabetes and peripheral neuropathy. CONCLUSIONS: Torque related parameters in patients with type II diabetes with or without peripheral neuropathy, are different from healthy subjects. As a result, patients with diabetes especially with peripheral neuropathy are more susceptible of injury and disability in lower limbs.

Effects of tool handle dimension and workpiece orientation and size on wrist ulnar/radial torque strength, usability and discomfort in a wrench task.

The effects of tool handle dimension (three modified designs of wrenches with 30-50 mm diameter cylindrical handles and traditional design with rectangular cross-sectional (5 mm × 25 mm) handle), workpiece orientation (vertical/horizontal) and workpiece size (small/large) as well as user's hand size on wrist ulnar/radial (U/R) torque strength, usability and discomfort, and also the relationship between these variables were evaluated in a maximum torque task using wrenches. The highest and lowest levels of maximal wrist U/R torque strength were recorded for the 30 mm diameter handle and traditional wrench design, respectively. The prototype handle with 30 mm diameter, together with 40 mm diameter handle, was also better than other designs as they received higher usability ratings and caused less discomfort. The mean wrist torque strength exerted on a vertically oriented workpiece (in the sagittal plane) was 23.8% higher than that exerted on a horizontally oriented one (in the transverse plane). The user's hand size had no effect on torque exertions. The wrist torque strength and usability were negatively correlated with hand and finger discomfort ratings. The results are also discussed in terms of their implications for hand tool and workstation configuration in torque tasks involving wrenches.

Effects of Stabilization Exercises Focusing on Pelvic Floor Muscles on Low Back Pain and Urinary Incontinence in Women.

OBJECTIVE: To investigate the effects of stabilization exercises focusing on pelvic floor muscles on both low back pain (LBP) and urinary incontinence (UI) in women suffering from chronic nonspecific LBP. METHODS: In a randomized clinical trial, 60 women, ranging from 45 to 60 years old, with chronic nonspecific LBP and stress UI were recruited. They were randomly assigned to the control group (n = 30) that received routine physiotherapy modalities and regular exercises, or the training group (n = 30) that received routine physiotherapy modalities and stabilization exercises focusing on pelvic floor muscle (12 weeks). Clinical characteristics of the study subjects including UI intensity and quality of life assessed by International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form questionnaire, functional disability assessed by Oswestry disability index scores, pain intensity, pelvic floor muscle strength and endurance, and transverses abdominis muscle strength were measured before and after treatment. RESULTS: Functional disability and pain intensity were significantly decreased in control (P < .05) and training groups (P < .05), with no significant difference between the groups after treatment. However, UI intensity was smaller for the training group (P < .05). Pelvic floor muscle strength and endurance, and transverses abdominis muscle strength were statistically increased in the training group compared with those in the control group (P < .05). CONCLUSION: Stabilization exercises focusing on pelvic floor muscle improves stress UI as well as LBP in women with chronic nonspecific LBP.

Correlation between Hip Rotation Range-of-Motion Impairment and Low Back Pain. A Literature Review.

BACKGROUND: Hip rotation range-of-motion (ROM) impairment has been proposed as a contributing mechanical factor in the development of low back pain (LBP) symptoms. There is a hypothesis which suggests that a limited range of hip rotation results in compensatory lumbar spine rotation. Hence, LBP may develop as the result. This article reviews studies assessing hip rotation ROM impairment in the LBP population. MATERIAL AND METHODS: The MEDLINE and EMBASE databases were searched without time restriction. Two authors independently selected related articles using the same search strategy and key words. RESULTS: Among 124 articles 12 met the review inclusion criteria. The results of the studies are assessed in three sections, investigating the relationship between low back pain and 1) hip internal rotation ROM, 2) hip external rotation ROM and 3) hip total rotation ROM. Asymmetrical (right versus left, lead versus non-lead) and limited hip internal rotation ROM were common findings in patients with LBP. Reduced and asymmetrical total hip rotation was also observed in patients with LBP. However, none of the studies explicitly reported limited hip external rotation ROM. CONCLUSION: The precise assessment of hip rotation ROM, especially hip internal rotation ROM, must be included in the examination of patients with LBP symptoms.

Physiotherapy for women with stress urinary incontinence: a review article.

[Purpose] This review article is designed to expose physiotherapists to a physiotherapy assessment of stress urinary incontinence (SUI) and the treatment and possibly preventive roles that they might play for women with SUI. Specifically, the goal of this article is to provide an understanding of pelvic floor muscle function and the implications that this function has for physiotherapy treatment by reviewing articles published in this area. [Methods] A range of databases was searched to identify articles that address physiotherapy for SUI, including the Cochrane Library, Medline, and CINAHL. [Results] According to the articles identified in our databases research, greater improvements in SUI occur when women receive a supervised exercise program of at least three months. The effectiveness of physiotherapy treatment is increased if the exercise program is based on some principles, such as intensity, duration, resembling functional task, and the position in which the exercise for pelvic floor muscles is performed. Biofeedback and electrical stimulation may also be clinically useful and acceptable modalities for some women with SUI. [Conclusion] We concluded that the plan for physiotherapy care should be individualized for each patient and include standard physiotherapy interventions.

Comparison of tap water and normal saline iontophoresis in idiopathic hyperhidrosis: a case report.

[Purpose] The purpose of this study was to evaluate the efficacy of tap water (drinking water) and normal saline (sodium chloride solution 0.9%) iontophoresis treatment for a patient with idiopathic hyperhidrosis [Subjects and Methods] In this study, tap water and normal saline iontophoresis were used to treat a 21 year-old female who was suffering from severe palmoplantar idiopathic hyperhidrosis. Post-iontophoresis sweat intensity of 8 treatment sessions were averaged and then normalized relative to the corresponding mean value which was obtained before iontophoresis treatment. [Results] The subject showed 24.72% and 42.01% decreases in sweat intensity following tap water and normal saline iontophoresis, respectively. [Conclusion] Tap water and normal saline iontophoresis are effective in the treatment of idiopathic hyperhidrosis. However, normal saline iontophoresis is 1.7 times more effective than tapwater iontophoresis at obstructing secretion.

Effects of neuromobilization maneuver on clinical and electrophysiological measures of patients with carpal tunnel syndrome.

[Purpose] The aim of this study was to investigate the efficacy of neuromobilization combined with routine physiotherapy in patients with carpal tunnel syndrome through subjective, physical, and electrophysiological studies. [Subjects and Methods] Twenty patients with carpal tunnel syndrome (totally 32 hands) were assigned two groups: treatment and control groups. In both groups, patients received the routine physiotherapy. In addition to the routine physiotherapy, patients in the treatment group received neuromobilization. The symptoms severity scale, visual analogue scale, functional status scale, Phalen's sign, median nerve tension test, and median nerve distal sensory and motor latency were assessed. [Results] There were significant improvements in the symptoms severity scale, visual analogue scale, median nerve tension test, and Phalen's sign in both groups. However, the functional status scale and median nerve distal motor latency were significantly improved only in the treatment group. [Conclusion] Neuromobilization in combination with routine physiotherapy improves some clinical findings more effectively than routine physiotherapy. Therefore, this combination can be used as an alternative effective non-invasive treatment for patients with carpal tunnel syndrome.

Reliability of upper limb tension test 1 in normal subjects and patients with carpal tunnel syndrome.

BACKGROUND AND OBJECTIVE: Tension tests or neurodynamic techniques assess the mobility of the peripheral nerves and provide a guide for planning and managing physiotherapy treatments of entrapment syndromes such as carpal tunnel syndrome (CTS). One of the upper limb tension tests (ULTT) is ULTT1 that evaluates the efficacy of physiotherapy treatment. It has been shown to be a valid test but its reliability has not been investigated for CTS. Therefore, it is not known if the ULTT1 helps in diagnosing CTS and assessing CTS treatments. The purpose of this study was to determine the reliability of the ULTT1 in CTS. MATERIAL AND METHODS: In order to determine the reliability of the ULTT1, we tested 23 healthy subjects and 12 subjects with CTS on two separate test days. Outcome measure for this study was elbow extension. RESULTS: Inter subject elbow extensions were not significantly different between the two test days. Also, the coefficient of correlation ± SEM in healthy and CTS subjects were 0.89 ± 1.23 degrees and 0.84 ± 3.67 degrees, respectively. CONCLUSION: From the above results, we conclude that the ULTT1 is highly reliable and can be used in diagnosis as well as the management of CTS.

Activation-induced force enhancement in human adductor pollicis.

It has been known for a long time that the steady-state isometric force after muscle stretch is bigger than the corresponding force obtained in a purely isometric contraction for electrically stimulated and maximal voluntary contractions (MVC). Recent studies using sub-maximal voluntary contractions showed that force enhancement only occurred in a sub-group of subjects suggesting that force enhancement for sub-maximal voluntary contractions has properties different from those of electrically-induced and maximal voluntary contractions. Specifically, force enhancement for sub-maximal voluntary contractions may contain an activation-dependent component that is independent of muscle stretching. To address this hypothesis, we tested for force enhancement using (i) sub-maximal electrically-induced contractions and stretch and (ii) using various activation levels preceding an isometric reference contraction at 30% of MVC (no stretch). All tests were performed on human adductor pollicis muscles. Force enhancement following stretching was found for all subjects (n=10) and all activation levels (10%, 30%, and 60% of MVC) for electrically-induced contractions. In contrast, force enhancement at 30% of MVC, preceded by 6s of 10%, 60%, and 100% of MVC was only found in a sub-set of the subjects and only for the 60% and 100% conditions. This result suggests that there is an activation-dependent force enhancement for some subjects for sub-maximal voluntary contractions. This activation-dependent force enhancement was always smaller than the stretch-induced force enhancement obtained at the corresponding activation levels. Active muscle stretching increased the force enhancement in all subjects, independent whether they showed activation dependence or not. It appears that post-activation potentiation, and the associated phosphorylation of the myosin light chains, might account for the stretch-independent force enhancement observed here.

Force depression following muscle shortening in sub-maximal voluntary contractions of human adductor pollicis.

Mechanical properties of skeletal muscles are often studied for controlled, electrically induced, maximal, or supra-maximal contractions. However, many mechanical properties, such as the force-length relationship and force enhancement following active muscle stretching, are quite different for maximal and sub-maximal, or electrically induced and voluntary contractions. Force depression, the loss of force observed following active muscle shortening, has been observed and is well documented for electrically induced and maximal voluntary contractions. Since sub-maximal voluntary contractions are arguably the most important for everyday movement analysis and for biomechanical models of skeletal muscle function, it is important to study force depression properties under these conditions. Therefore, the purpose of this study was to examine force depression following sub-maximal, voluntary contractions. Sets of isometric reference and isometric-shortening-isometric test contractions at 30% of maximal voluntary effort were performed with the adductor pollicis muscle. All reference and test contractions were executed by controlling force or activation using a feedback system. Test contractions included adductor pollicis shortening over 10 degrees, 20 degrees, and 30 degrees of thumb adduction. Force depression was assessed by comparing the steady-state isometric forces (activation control) or average electromyograms (EMGs) (force control) following active muscle shortening with those obtained in the corresponding isometric reference contractions. Force was decreased by 20% and average EMG was increased by 18% in the shortening test contractions compared to the isometric reference contractions. Furthermore, force depression was increased with increasing shortening amplitudes, and the relative magnitudes of force depression were similar to those found in electrically stimulated and maximal contractions. We conclude from these results that force depression occurs in sub-maximal voluntary contractions, and that force depression may play a role in the mechanics of everyday movements, and therefore may have to be considered in biomechanical models of human movement.

The dependence of force enhancement on activation in human adductor pollicis.

It has been well recognized that the steady-state isometric force after active muscle/fiber stretch is greater than the corresponding isometric force for electrically stimulated muscles and maximal voluntary contractions (MVC). However, recent evidence obtained for sub-MVC suggests that force enhancement properties are different from those observed for electrically induced and MVC. Specifically, it appears that force enhancement is activation-dependent and that there is a subject-specific threshold for force enhancement in sub-MVC. To address these suggestions, the relationship between force enhancement and voluntary activation during stretch was investigated in 11 healthy subjects. Human adductor pollicis muscles were studied and force enhancement was measured while muscle activation during the steady-state isometric phase was controlled at a level of 30% of MVC. In order to study the effects of activation on force enhancement, subjects performed stretch contractions at 0, 10, 30, 60, and 100% of maximal voluntary effort while the steady-state isometric force after stretch, obtained at 30% of activation in all cases, was compared to the corresponding values measured in the isometric reference contractions. There was no force enhancement if muscle stretching occurred passively but all subjects showed force enhancement when muscle stretching occurred at maximal voluntary effort. When increasing the level of activation during the stretch phase, force enhancement increased, and the number of subjects who showed force enhancement increased as well. We conclude from these results that force enhancement during voluntary contractions is activation-dependent with a threshold that is subject-specific.

Force enhancement at different levels of voluntary contraction in human adductor pollicis.

There is substantial evidence that the steady-state isometric force following active muscle stretch is greater than the corresponding isometric force for sub-maximal and maximal electrically induced contractions, and for maximal voluntary contractions (MVC). This so-called force enhancement (FE) has not been investigated systematically for sub-MVC. Recently, we found that FE only occurred in about half of all tested subjects at 30% of MVC in the adductor pollicis muscle, suggesting that FE for voluntary contractions might depend on the level of activation. Therefore, the purpose of this study was to determine if FE during voluntary contractions is associated with activation. We hypothesized that FE increases with increasing levels of activation, and thus increasing levels of effort. Subjects (n=12) performed voluntary contractions of the adductor pollicis using a custom-built dynamometer at 10 and 60% of maximal effort. There was consistent FE in 4 of 12 subjects at 10% and in 10 of 12 subjects at 60% of maximal voluntary effort. Furthermore, the absolute FE increased from 10 to 60% of maximal voluntary effort. The results of this study, together with previous results on the same subject group at 30% and other subjects at 100% of maximal voluntary effort, suggest that FE systematically increases with increasing levels of voluntary contraction. The mechanisms responsible for this increased FE remain unclear.

Observations on force enhancement in submaximal voluntary contractions of human adductor pollicis muscle.

It has been observed consistently and is well accepted that the steady-state isometric force after active muscle stretch is greater than the corresponding isometric force for electrically stimulated muscles and maximal voluntary contractions. However, this so-called force enhancement has not been studied for submaximal voluntary efforts; therefore, it is not known whether this property affects everyday movements. The purpose of this study was to determine whether there was force enhancement during submaximal voluntary contractions. Human adductor pollicis muscles (n = 17) were studied using a custom-built dynamometer, and both force and activation were measured while muscle activation and force were controlled at a level of 30% of maximal voluntary contraction. The steady-state isometric force and activation after active stretch were compared with the corresponding values obtained during isometric reference contractions. There was consistent and reliable force enhancement in 8 of the 17 subjects, whereas there was no force enhancement in the remaining subjects. Subjects with force enhancement had greater postactivation potentiation and a smaller resistance to fatigue in the adductor pollicis. We conclude from these results that force enhancement exists during submaximal voluntary contractions in a subset of the populations and suggest that it may affect everyday voluntary movements in this subset. On the basis of follow-up testing, it appears that force enhancement during voluntary contractions is linked to potentiation and fatigue resistance and therefore possibly to the fiber-type distribution in the adductor pollicis muscle.