Electromyographic study during isometric exercise of the shoulder in head-out water immersion

Comparison of Subjective Workout Intensities between Aquatic and Land-based Running in Healthy Young Males: A Pilot Study

Background and objectives: Aquatic exercises have demonstrated several advantages over land-based exercise, but only a few studies have compared the workout intensities and efficiencies in a stage-specific manner. This study aimed to investigate workout intensity during aquatic and land-based running, based on the rating of perceived exertion (RPE). Materials and Methods: Twenty healthy young male subjects underwent a land-based running test (LRT) and an aquatic running test (ART), in the form of a cardiopulmonary exercise treadmill test and a shallow-water running test. The seven stages of the ART were composed of 3 minutes each of the Bruce protocol performed during the LRT. In the ART, the participants were instructed to run in a swimming pool with matching RPE to that obtained at each stage of the LRT. Results: Heart rate (HR) during both LRT and ART exhibited a linear relationship (r = 0.997 and 0.996, respectively; p < 0.001). During the initial and middle period, HR was higher in the ART than in the LRT. However, in the final period, HR was higher in the LRT than in the ART. Conclusions: In aquatic exercises based on the RPE obtained from the LRT, HR exhibited a linear relationship in both the ART and the LRT. The ART appears to increase cardiac loading more efficiently in the initial period and does not increase cardiac loading abruptly at a later period. Although there is no precise, objective, controlled parameter to compare the ART and the LRT, the RPE may be used as a convenient measurement for workout intensity in aquatic running.

Feasibility Testing of Hydrophobic Carbon Electrodes for Acquisition of Underwater Surface Electromyography Data

Underwater surface electromyography (sEMG) signals are especially of interest for rehabilitation and sports medicine applications. Silver/silver chloride (Ag/AgCl) hydrogel electrodes, although the gold standard for sEMG data collection, require waterproofing for underwater applications. Having to apply waterproof tape over electrodes impedes the deployment of sEMG in immersed conditions. As a better alternative for underwater applications, we have developed carbon black/polydimethylsiloxane (CB/PDMS) electrodes for collecting sEMG signals under water. We recruited twenty subjects to collect simultaneous recordings of sEMG signals using Ag/AgCl and CB/PDMS electrodes on biceps brachii, triceps brachii, and tibial anterior muscles. The Ag/AgCL electrodes were covered in waterproof tape, and the CB/PDMS electrodes were not. We found no differences in sEMG signal amplitudes between both sensors, for the three muscles. Moderate mean correlation between Ag/AgCl and CB/PDMS electrodes was found on the linear envelopes (≥ 0.7); correlation was higher for power spectral densities (≥ 0.84). Ag/AgCl electrodes performed better in response to noise, whilst the CB/PDMS electrodes were more sensitive to myoelectric activity in triceps and tibialis, and exhibited better response to motion artifacts in the measurements on the triceps and tibialis. Results suggest that sEMG signal collection is possible under water using CB/PDMS electrodes without requiring any waterproof or adhesive tape.

Comparison of an Innovative Rehabilitation, Combining Reduced Conventional Rehabilitation with Balneotherapy, and a Conventional Rehabilitation after Anterior Cruciate Ligament Reconstruction in Athletes

Background

Instability of the knee, related to anterior cruciate ligament injury, is treated by surgical reconstruction. During recovery, a loss of proprioceptive input can have a significant impact. Few studies have evaluated the benefits of rehabilitation of the knee in aquatic environment on functional outcomes.

Objective

This study aimed to compare an innovative rehabilitation protocol combining reduced conventional rehabilitation with aquatic rehabilitation, with a conventional rehabilitation, according to the National French Health Authority, in terms of kinetics, development of proprioceptive skills, and functional improvement of the knee.

Methods

67 patients, who were amateur or professional athletes, were randomized into two groups: 35 patients followed the conventional rehabilitation protocol (Gr1) and 32 patients followed the innovative rehabilitation protocol (Gr2). Patients were evaluated before surgery, and at 2 weeks, 1, 2, and 6 months after surgery using posturography, and evaluation of muscular strength, walking performance and proprioception. This study is multicenter, prospective, randomized, and controlled with a group of patients following conventional rehabilitation (level of evidence I).

Results

For the same quality of postural control, Gr2 relied more on somesthesia than Gr1 at 6 months. The affected side had an impact on postural control and in particular on the preoperative lateralization, at 2 weeks and at 1 month. Lateralization depended on the affected knee, with less important lateralization in Gr2 preoperatively and at 1 month. The quadriceps muscular strength was higher in Gr2 than in Gr1 at 2 and 6 months and muscle strength of the external hamstring was greater in Gr2 than in Gr1 at 6 months. The isokinetic test showed a greater quadriceps muscular strength in Gr2. Gr2 showed a greater walking distance than Gr1 at one month. Gr2 showed an improvement in the proprioceptive capacities of the operated limb in flexion for the first 2 months.

Conclusion

The effectiveness of the innovative rehabilitation program permits faster recovery, allowing for an earlier return to social, sporting, and professional activities. Faster retrieval of knee function following aquatic rehabilitation would prevent both short-term risk of lesions of the contralateral limb due to overcompensation and long-term risk of surgery due to osteoarthritis.

Registration of clinical trials

NCT02225613.

Rehabilitation after Rotator Cuff Repair

BACKGROUND

Rotator cuff tears are a very common condition that is often incapacitating. Whether non-surgical or surgical, successful management of rotator cuff disease is dependent on appropriate rehabilitation. If conservative management is insufficient, surgical repair is often indicated. Postsurgical outcomes for patients having had rotator cuff repair can be quite good. A successful outcome is much dependent on surgical technique as it is on rehabilitation. Numerous rehabilitation protocols for the management of rotator cuff disease are based primarily on clinical experience and expert opinion. This article describes the different rehabilitation protocols that aim to protect the repair in the immediate postoperative period, minimize postoperative stiffness and muscle atrophy.

METHODS

A review of currently available literature on rehabilitation after arthroscopic rotator cuff tear repair was performed to illustrate the available evidence behind various postoperative treatment modalities.

RESULTS

There were no statistically significant differences between a conservative and an accelerated rehabilitation protocol . Early passive range of motion (ROM) following arthroscopic cuff repair is thought to decrease postoperative stiffness and improve functionality. However, early aggressive rehabilitation may compromise repair integrity.

CONCLUSION

The currently available literature did not identify any significant differences in functional outcomes and relative risks of re-tears between delayed and early motion in patients undergoing arthroscopic rotator cuff repairs. A gentle rehabilitation protocol with limits in range of motion and exercise times after arthroscopic rotator cuff repair would be better for tendon healing without taking any substantial risks. A close communication between the surgeon, the patient and the physical therapy team is important and should continue throughout the whole recovery process.

Surface electromyography during physical exercise in water: a systematic review

BACKGROUND

Aquatic exercise has been widely used for rehabilitation and functional recovery due to its physical and physiological benefits. However, there is a high variability in reporting on the muscle activity from surface electromyographic (sEMG) signals. The aim of this study is to present an updated review of the literature on the state of the art of muscle activity recorded using sEMG during activities and exercise performed by humans in water.

METHODS

A literature search was performed to identify studies of aquatic exercise movement.

RESULTS

Twenty-one studies were selected for critical appraisal. Sample size, functional tasks analyzed, and muscles recorded were studied for each paper. The clinical contribution of the paper was evaluated.

CONCLUSIONS

Muscle activity tends to be lower in water-based compared to land-based activity; however more research is needed to understand why. Approaches from basic and applied sciences could support the understanding of relevant aspects for clinical practice.

Analysis of arm elevation muscle activity through different movement planes and speeds during in-water and dry-land exercise

OBJECTIVE

The objectives of this cross-sectional, analytical inference analysis were to compare shoulder muscle activation at arm elevations of 0° to 90° through different movement planes and speeds during in-water and dry-land exercise and to extrapolate this information to a clinical rehabilitation model.

METHODS

Six muscles of right-handed adult subjects (n = 16; males/females: 50%; age: 26.1 ± 4.5 years) were examined with surface electromyography during arm elevation in water and on dry land. Participants randomly performed 3 elevation movements (flexion, abduction, and scaption) through 0° to 90°. Three movement speeds were used for each movement as determined by a metronome (30°/sec, 45°/sec, and 90°/sec). Dry-land maximal voluntary contraction tests were used to determine movement normalization.

RESULTS

Muscle activity levels were significantly lower in water compared with dry land at 30°/sec and 45°/sec but significantly higher at 90°/sec. This sequential progressive activation with increased movement speed was proportionally higher on transition from gravity-based on-land activity to water-based isokinetic resistance. The pectoralis major and latissimus dorsi muscles showed higher activity during abduction and scaption.

CONCLUSIONS

These findings on muscle activation suggest protocols in which active flexion is introduced first at low speeds (30°/sec) in water, then at medium speeds (45°/sec) in water or on dry land, and finally at high speeds (90°/sec) on dry land before in water. Abduction requires higher stabilization, necessitating its introduction after flexion, with scaption introduced last. This model of progressive sequential movement ensures that early active motion and then stabilization are appropriately introduced. This should reduce rehabilitation time and improve therapeutic goals without compromising patient safety or introducing inappropriate muscle recruitment or movement speed.

Early aquatic physical therapy improves function and does not increase risk of wound-related adverse events for adults after orthopedic surgery: a systematic review and meta-analysis

OBJECTIVES

To investigate whether early postoperative aquatic physical therapy is a low-risk and effective form of physical therapy to improve functional outcomes after orthopedic surgery.

DATA SOURCES

Databases MEDLINE, CINAHL, AMED, Embase, and PEDro were searched from the earliest date available until October 2011. Additional trials were identified by searching reference lists and citation tracking.

STUDY SELECTION

Controlled trials evaluating the effects of aquatic physical therapy on adverse events for adults <3 months after orthopedic surgery. Two reviewers independently applied inclusion and exclusion criteria, and any disagreements were discussed until consensus could be reached. Searching identified 5069 potentially relevant articles, of which 8 controlled trials with 287 participants met inclusion criteria.

DATA EXTRACTION

A predefined data extraction form was completed in detail for each included study by 1 reviewer and checked for accuracy by another. Methodologic quality of included trials was assessed independently by 2 reviewers using the PEDro scale.

DATA SYNTHESIS

Pooled analyses were performed using random effects model with inverse variance methods to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs) (continuous outcomes) and risk difference and 95% CIs (dichotomous outcomes). When compared with land-based physical therapy, early aquatic physical therapy does not increase the risk of wound-related adverse events (risk difference=.01, 95% CI -.05 to .07) and results in improved performance of activities of daily living (SMD=.33, 95% CI=.07-.58, I(2)=0%). There were no significant differences in edema (SMD=-.27, 95% CI=-.81 to .27, I(2)=58%) or pain (SMD=-.06, 95% CI=-.50 to .38, I(2)=32%).

CONCLUSIONS

After orthopedic surgery aquatic physical therapy improves function and does not increase the risk of wound-related adverse events and is as effective as land-based therapy in terms of pain, edema, strength, and range of motion in the early postoperative period.

Activation of the shoulder musculature during pendulum exercises and light activities

STUDY DESIGN

Prospective, single-group, repeated-measures design.

OBJECTIVES

To evaluate electromyographic (EMG) signal amplitude in the supraspinatus, infraspinatus, and deltoid muscles during pendulum exercises and light activities in a group of healthy subjects.

BACKGROUND

There are numerous rehabilitation protocols used after rotator cuff repair. One of the most commonly used exercises in these protocols is the pendulum. Patients can easily perform these exercises incorrectly, and may also perform light activities of daily living without knowing that they may be putting excessive stress on the repair. The effect of improperly performed pendulum exercises and light activities after rotator cuff repair is unknown.

METHODS

Muscle activity was recorded in 13 subjects performing pendulum exercises incorrectly and correctly in both large (51-cm) and small (20-cm) diameters, and while typing, drinking, and brushing their teeth.

RESULTS

Incorrect and correct large pendulums and drinking elicited more than 15% maximum voluntary isometric contraction in the supraspinatus and infraspinatus. The supraspinatus EMG signal amplitude was greater during large, incorrectly performed pendulums than during those performed correctly. Both correct and incorrect large pendulums resulted in statistically higher muscle activity in the supraspinatus than the small pendulums.

CONCLUSION

Larger pendulums may require more force than is desirable early in rehabilitation after rotator cuff repair.

Shoulder abduction moment arms in three clinically important positions

The abduction moment arms of 4 shoulder muscles were calculated in clinically important positions to evaluate the best test situation for the supraspinatus based on its mechanical advantage.Moment arms of the supraspinatus, infraspinatus, and middle and anterior deltoid in 18 individuals were computed using individual magnetic resonance imaging data and a computer-assisted design tool for simulation. Three tests with the arm in the neutral position (arm hanging on side), at 90 of scaption,and at 90 of scaption and full internal humeral rotation (Jobe test) were investigated. The supraspinatushas a greater mechanical advantage vs the other tested muscles in the neutral arm position. In the Jobe position, the supraspinatus' abduction moment arm is reduced with increased internal humeral rotation.Comparing these results with the literature indicates that this new method is adequate for calculation of moment arms and may be used in any desired joint configuration.

A method for monitoring intensity during aquatic resistance exercises

The aims of this study were (i) to check whether monitoring of both the rhythm of execution and the perceived effort is a valid tool for reproducing the same intensity of effort in different sets of the same aquatic resistance exercise (ARE) and (ii) to assess whether this method allows the ARE to be put at the same intensity level as its equivalent carried out on dry land. Four healthy trained young men performed horizontal shoulder abduction and adduction (HSAb/Ad) movements in water and on dry land. Muscle activation was recorded using surface electromyography of 1 stabilizer and several agonist muscles. Before the final tests, the ARE movement cadence was established individually following a rhythmic digitalized sequence of beats to define the alternate HSAb/Ad movements. This cadence allowed the subject to perform 15 repetitions at a perceived exertion of 9-10 using Hydro-Tone Bells. After that, each subject performed 2 nonconsecutive ARE sets. The dry land exercises (1 set of HSAb and 1 set of HSAd) were performed using a dual adjustable pulley cable motion machine, with the previous selection of weights that allowed the same movement cadence to be maintained and the completion of the same repetitions in each of the sets as with the ARE. The average normalized data were compared for the exercises in order to determine possible differences in muscle activity. The results show the validity of this method for reproducing the intensity of effort in different sets of the same ARE, but is not valid for matching the same intensity level as kinematically similar land-based exercises.

The addition of aquatic therapy to rehabilitation following surgical rotator cuff repair: a feasibility study

BACKGROUND AND PURPOSE

Rotator cuff tears are frequently encountered in medical outpatient settings and often require surgical repair to achieve desirable functional outcomes. However, the optimal form of post-operative rehabilitation of rotator cuff repairs remains unidentified by the research literature. The aim of this study was to determine the feasibility of implementing and investigating the effect of a combined aquatic and land-based rehabilitation programme in the post-operative rehabilitation of rotator cuff tears.

METHODS

A cohort of 18 subjects undergoing rotator cuff repair were examined over a treatment period of 12 weeks. Twelve subjects participated in a combined aquatic and land-based programme, while six subjects received a standard land-based protocol. Passive range of motion and the Western Ontario Rotator Cuff Index outcomes were measured pre-operatively and at three, six and 12 weeks, post-operatively. Subjective responses on patient's assurance and confidence in the value of the exercises (questionnaire using an 11-point Visual Analogue Scale (VAS)) were collected at 12 weeks for both groups.

RESULTS

There was a significant improvement in both range of motion and Western Ontario Rotator Cuff scores in all subjects with treatment (p < 0.001). Furthermore, participation in aquatic therapy significantly improved passive flexion range of motion measures at three weeks (mean 46 degrees , 95% CI 17-75, p = 0.005) and six weeks (30 degrees , 95% CI 8-51, p = 0.01). There was no significant difference in the attendance rates (80% in both groups) or patients perceptions of the programmes (100% confidence and assurance in both groups).

CONCLUSION

The implementation of a combined aquatic and land-based physiotherapy programme following surgical repair of the rotator cuff is feasible and presents a potential viable alternative to conventional land-based exercise with comparable outcomes.

Numerical analysis of cooperative abduction muscle forces in a human shoulder joint

Because some shoulder muscles originate from a wide area, the modeling of such muscles has been a significant problem in a computer simulation. We demonstrated a new method of determining a vector for each of the muscles originating from a wide area. A 3-dimensional musculoskeletal model of a human shoulder was constructed from computed tomography data of a normal volunteer. Numerical analysis of 11 muscle forces and the joint reaction force during shoulder abduction from 10 degrees to 150 degrees was performed from the static equilibrium equations. An optimal origin point for the vector of the muscle with a wide origin area was determined in every analyzed position. Electromyography was carried out to validate the results of the simulation, and a significant correlation with the analyzed force was obtained in each muscle. The anatomic biomechanical model with the new muscle modeling method led to the results reflecting the actual muscle activities in a living body.

Confounding factors in water EMG recordings: an approach to a definitive standard

This work presents a study on the influence of the aqueous environment on the surface EMG (sEMG) signal recorded in bipolar montage from the abductor pollicis brevis muscle, when only the forearm is immersed in water. Ten men, 30.1+/-4.0 (mean +/- SD) years old, performed ten 2-s 40% MVC isometric contractions of the abductor pollicis brevis muscle in two controlled environments (air and water, at a temperature of 32 degrees C). They were always equipped with electrodes protected with a waterproof adhesive tape. No significant variations (paired Wilcoxon test) due to the environments were observed in the median frequency of the power spectrum (MDF) and in the root mean square (RMS) value of the sEMG signal. These results allow us to assess the methodological criteria to properly record sEMG signals in water and provide the basis to explain different findings obtained by other authors.

Muscle activity and heart rate response during backward walking in water and on dry land

The primary purpose of this study was to examine whether walking backward in water and walking backward on dry land elicit different electromyographic (EMG) activities in lower-extremity and trunk muscles. Surface EMG was used to evaluate muscle activities while six healthy subjects walked backward in water (with and without a water current, Water + Cur and Water - Cur, respectively) immersed to the level of the xiphoid process, and while they walked backward on dry land (DL). The trials in water utilized the Flowmill which consists of a treadmill at the base of a water flume. Integrated EMG analysis allowed the quantification of muscle activities. The measurement of maximal voluntary contraction (MVC) of each muscle was made prior to the gait analysis, and all data were expressed as the mean (SD). The %MVCs from the muscles tested while walking backward in water (both with and without a current) were all significantly lower than those obtained while walking backward on dry land (P < 0.05), with the exception of the paraspinal muscles. In the case of the paraspinal muscles, the %MVC while walking backward with a water current was significantly greater than when walking backward on dry land [Water + Cur 19.4 (6.8)%MVC vs. DL 13.1 (1.4)%MVC; P < 0.05], or walking backward without a water current [vs. Water - Cur 13.3 (1.8)%MVC; P < 0.05]. Furthermore, when walking backward in water, the %MVCs from the muscles investigated were significantly greater in the presence of a water current than without (P < 0.05). In conclusion, walking backward in water with a current elicits the greatest muscle activation of the paraspinal muscles. These data may help in the development of water-based exercise programs.

Evaluation of muscle metabolic activity in the lower limb of a transfemoral amputee using a prosthesis by using (18)F-FDG PET imaging--an application of PET imaging to rehabilitation

This study used FDG PET to evaluate the lower limb muscles metabolic activities of transfemoral amputees during walking with prostheses. As a preliminary study, FDG PET was applied for two normal adult volunteers to evaluate muscle activity in the lower extremities after gait exercise. This same method was applied for two amputee volunteers with prostheses. We found that FDG accumulated more in both gluteus medius muscles after gait exercise compared to other muscles in normal adult volunteers. In the skilled amputee volunteer, FDG uptake increased in the adductor and gluteus medius in the amputated side, while in the unskilled the adductor, gluteus maximus, and gluteus medius showed increased FDG uptake only in the normal side. This result suggests that basic metabolic changes such as an increase in oxidative metabolism and less reliance on glycolytic activity would occur as a result of skeletal muscle training in amputees.

Surface EMG alterations induced by underwater recording

BACKGROUND AND PURPOSE

This study aims to verify if amplitude and spectral characteristics of surface EMG signal are modified due to recording in a wet environment.

METHODS

Isometric contractions of the biceps brachii muscle of ten subjects were performed in several different set-up combinations, both in dry (D) and in water from hydrotherapy pools (PW), with (PWM) or without moving the pool water and with (T) or without water-resistant adhesive taping.

RESULTS

In PW condition the amplitude of the recorded signal is reduced to 5-10% of the corresponding signal recorded in D condition. In PWM the power spectrum is drastically reduced and altered by the water movement that introduces an increase of spectral power in the frequency range 0-20 Hz. The use of T modality allows to record signals with both amplitude and spectral frequencies comparable with those obtained in the D conditions.

DISCUSSION AND CONCLUSION

This work demonstrates the need for water resistant taping when EMG signals are recorded in water. Signals recorded without such a protective film are strongly affected in their amplitude and frequency characteristics by the conductivity and the movement of water.

Electromyographic Analysis of Walking in Water in Healthy Humans

This study was designed to describe and clarify muscle activities which occur while walking in water. Surface electromyography (EMG) was used to evaluate muscle activities in six healthy subjects (mean age, 23.3 +/- 1.4 years) while they walked on a treadmill in water (with or without a water current) immersed to the level of the xiphoid process, and while they walked on a treadmill on dry land. The trials in water utilized the Flowmill which has a treadmill at the base of a water flume. Integrated EMG analysis was conducted for the quantification of muscle activities. In order to calculate the %MVC, the measurement of maximal voluntary contraction (MVC) of each muscle was made before the gait analysis, thus facilitating a comparison of muscle activities while walking in water with those on dry land. The %MVCs obtained from each of the tested muscles while walking in water, both with and without a water current, were all found to be lower than those obtained while walking on dry land at a level of heart rate response similar to that used when walking on dry land. Furthermore, the %MVCs while walking in water with a water current tended to be greater when compared to those while walking in water without a water current. In conclusion, the present study demonstrated that muscle activities while walking in water were significantly decreased when compared to muscle activities while walking on dry land, that muscle activities while walking in water tended to be greater with a water current than without, and that the magnitude of the muscle activity in water was relatively small in healthy humans. This information is important to design water-based exercise programs that can be safely applied for rehabilitative and recreational purposes.

Use of 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography (FDG PET) imaging for the evaluation of muscle metabolic activity in ruptured rotator cuffs: Identification of shoulder muscles by fusion imaging studies involving both FDG PET and magnetic resonance imaging

The uptake of 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) into shoulder muscles was studied in 11 patients with rotator cuff tears. FDG was injected under resting conditions, and cuff muscle exercises were performed followed by evaluation of the standardized uptake value (SUV) in shoulder muscles bilaterally. Analysis was performed with a subtracted SUV, obtained by subtracting the SUV of the muscle at rest from that after exercise. Fusion imaging studies involving FDG positron emission tomography (PET) and magnetic resonance imaging would provide a novel strategy with the potential of improving on the limited resolution of PET images. In this study this relatively new strategy revealed a similar decrease in the supraspinatus SUV in cases involving both complete and partial tears. The SUV in the infraspinatus and subscapularis also decreased, regardless of whether these muscles were intact or ruptured; the SUV in the deltoid remained basically unchanged. With the use of this exercise protocol, FDG PET might prove useful for objective evaluation of rotator cuff muscle activity.

Electromyographic and kinematic analysis of therapeutic knee exercises under water

OBJECTIVE

This study aimed to evaluate muscle function and kinematics during commonly used knee rehabilitation exercises performed in water.

DESIGN

Maximal effort single extension and flexion trials in still water and repeated extension-flexion trials in flowing water in barefoot condition were analysed from 18 healthy participants (8 men, 10 women).

BACKGROUND

Despite the fact that water exercises are widely used, there are only few studies involving biomechanical and hydrodynamical analysis of aquatic exercises in rehabilitation.

METHODS

Electromyography of the quadriceps (vastus medialis, vastus lateralis) and hamstring muscles (biceps femoris, semitendinosus) and angular velocities of the movements were recorded under water.

RESULTS

In the repeated extension-flexion exercises the early reduction of agonist activity occurred concurrently with a high level of activity of the antagonists. In the single trial exercises the level of antagonistic activity was low throughout the range of motion, whereas the level of agonist activity was higher during the final phase of the range of motion as compared with the repeated exercises. Angular velocity patterns and values were similar between the two types of exercises.

CONCLUSIONS

The present data demonstrated that the flowing properties of water modified the neuromuscular function of the quadriceps and hamstring muscles acting as agonists and antagonists in the knee flexion-extension exercises.