Functional electrical stimulation-assisted cycle ergometry-based progressive mobility programme for mechanically ventilated patients: randomised controlled trial with 6 months follow-up.

PURPOSE: Functional electrical stimulation-assisted cycle ergometry (FESCE) enables in-bed leg exercise independently of patients' volition. We hypothesised that early use of FESCE-based progressive mobility programme improves physical function in survivors of critical care after 6 months. METHODS: We enrolled mechanically ventilated adults estimated to need >7 days of intensive care unit (ICU) stay into an assessor-blinded single centre randomised controlled trial to receive either FESCE-based protocolised or standard rehabilitation that continued up to day 28 or ICU discharge. RESULTS: We randomised in 1:1 ratio 150 patients (age 61±15 years, Acute Physiology and Chronic Health Evaluation II 21±7) at a median of 21 (IQR 19-43) hours after admission to ICU. Mean rehabilitation duration of rehabilitation delivered to intervention versus control group was 82 (IQR 66-97) versus 53 (IQR 50-57) min per treatment day, p<0.001. At 6 months 42 (56%) and 46 (61%) patients in interventional and control groups, respectively, were alive and available to follow-up (81.5% of prespecified sample size). Their Physical Component Summary of SF-36 (primary outcome) was not different at 6 months (50 (IQR 21-69) vs 49 (IQR 26-77); p=0.26). At ICU discharge, there were no differences in the ICU length of stay, functional performance, rectus femoris cross-sectional diameter or muscle power despite the daily nitrogen balance was being 0.6 (95% CI 0.2 to 1.0; p=0.004) gN/m2 less negative in the intervention group. CONCLUSION: Early delivery of FESCE-based protocolised rehabilitation to ICU patients does not improve physical functioning at 6 months in survivors. TRIAL REGISTRATION NUMBER: NCT02864745.

Step Ergometer Training Augmented With Functional Electrical Stimulation in Individuals With Chronic Spinal Cord Injury: A Feasibility Study.

Spinal cord injury (SCI) often results in loss of upright mobility and independence subsequently challenging rehabilitation practitioners for meaningful intervention strategies. The objective of this study was to evaluate the feasibility and potential impact on walking function of the stimulation and ergometer training protocol (STEP) in chronic SCI. Fourteen individuals with a chronic motor incomplete SCI (>1-year post injury) were enrolled in the study. The intervention consisted of a 12-week walking training program delivered three times per week from 20 up to 45 min in combination with 10 channels of FES on a step ergometer. Subsequent to this training, 30 min over ground walking training was performed. Ten out of the 14 participants completed the trial (71%). All participants who completed the intervention increased their walking speed by an average of 0.13 m/s (0.08) and walking endurance by an average of 117 ft (84 ft). For those who completed the trial, 50% demonstrated increases on the Walking Index for Spinal Cord Injury II by at least one level while 60% demonstrated an increase in lower extremity motor scores; all completing the Timed Up and Go Test at baseline demonstrated a reduction in time to complete during post-test evaluation. Recruitment objectives were attained. Overall retention was lower than anticipated with 29% withdrawing secondary to issues with lower extremity pain and exertional demands; however, no other adverse events occurred. Improvements in mobility outcomes generated by the STEP show promise in the context of feasibility and warrant further investigation to evaluate efficacy in comparison to other walking recovery interventions. The STEP was well-tolerated by participants who were >1 year and less than 10 years post SCI. Those completing the protocol exhibited improvements in commonly used SCI walking outcome measures.

Combined spiroergometry and 31 P-MRS of human calf muscle during high-intensity exercise.

Simultaneous measurements of pulmonary oxygen consumption (VO2 ), carbon dioxide exhalation (VCO2 ) and phosphorus magnetic resonance spectroscopy (31 P-MRS) are valuable in physiological studies to evaluate muscle metabolism during specific loads. Therefore, the aim of this study was to adapt a commercially available spirometric device to enable measurements of VO2 and VCO2 whilst simultaneously performing 31 P-MRS at 3 T. Volunteers performed intense plantar flexion of their right calf muscle inside the MR scanner against a pneumatic MR-compatible pedal ergometer. The use of a non-magnetic pneumotachograph and extension of the sampling line from 3 m to 5 m to place the spirometric device outside the MR scanner room did not affect adversely the measurements of VO2 and VCO2 . Response and delay times increased, on average, by at most 0.05 s and 0.79 s, respectively. Overall, we were able to demonstrate a feasible ventilation response (VO2 = 1.05 ± 0.31 L/min; VCO2 = 1.11 ± 0.33 L/min) during the exercise of a single calf muscle, as well as a good correlation between local energy metabolism and muscular acidification (τPCr fast and pH; R2 = 0.73, p < 0.005) and global respiration (τPCr fast and VO2 ; R2  = 0.55, p = 0.01). This provides improved insights into aerobic and anaerobic energy supply during strong muscular performances.

The Effects of Caffeine Supplementation on Physiological Responses to Submaximal Exercise in Endurance-Trained Men.

OBJECTIVES: The aim of this study was to evaluate the effects of caffeine on physiological responses to submaximal exercise, with a focus on blood lactate concentration ([BLa]). METHODS: Using a randomised, single-blind, crossover design; 16 endurance-trained, male cyclists (age: 38 ± 8 years; height: 1.80 ± 0.05 m; body mass: 76.6 ± 7.8 kg; [Formula: see text]: 4.3 ± 0.6 L∙min-1) completed four trials on an electromagnetically-braked cycle ergometer. Each trial consisted of a six-stage incremental test (3 minute stages) followed by 30 minutes of passive recovery. One hour before trials 2-4, participants ingested a capsule containing 5 mg∙kg-1 of either caffeine or placebo (maltodextrin). Trials 2 and 3 were designed to evaluate the effects of caffeine on various physiological responses during exercise and recovery. In contrast, Trial 4 was designed to evaluate the effects of caffeine on [BLa] during passive recovery from an end-exercise concentration of 4 mmol∙L-1. RESULTS: Relative to placebo, caffeine increased [BLa] during exercise, independent of exercise intensity (mean difference: 0.33 ± 0.41 mmol∙L-1; 95% likely range: 0.11 to 0.55 mmol∙L-1), but did not affect the time-course of [BLa] during recovery (p = 0.604). Caffeine reduced ratings of perceived exertion (mean difference: 0.5 ± 0.7; 95% likely range: 0.1 to 0.9) and heart rate (mean difference: 3.6 ± 4.2 b∙min-1; 95% likely range: 1.3 to 5.8 b∙min-1) during exercise, with the effect on the latter dissipating as exercise intensity increased. Supplement × exercise intensity interactions were observed for respiratory exchange ratio (p = 0.004) and minute ventilation (p = 0.034). CONCLUSIONS: The results of the present study illustrate the clear, though often subtle, effects of caffeine on physiological responses to submaximal exercise. Researchers should be aware of these responses, particularly when evaluating the physiological effects of various experimental interventions.

Designing adaptive integral sliding mode control for heart rate regulation during cycle-ergometer exercise using bio-feedback.

This paper considers our developed control system which aims to regulate the exercising subjects' heart rate (HR) to a predefined profile. The controller would be an adaptive integral sliding mode controller. Here it is assumed that the controller commands are interpreted as biofeedback auditory commands. These commands can be heard and implemented by the exercising subject as a part of the control-loop. However, transmitting a feedback signal while the pedals are not in the appropriate position to efficiently exert force may lead to a cognitive disengagement of the user from the feedback controller. To address this problem this paper will employ a different form of control system regarding as "actuator-based event-driven control system". This paper will claim that the developed event-driven controller makes it possible to effectively regulate HR to a predetermined HR profile.

Impact of an outpatient cardiac rehabilitation program on clinical and analytical variables in cardiovascular disease.

PURPOSE: The aim of the study was to determine the effect of lifestyle changes in patients participating in a cardiac rehabilitation program. METHODS: Patients with cardiovascular disease (N = 59) were enrolled in cardiac rehabilitation, which included nutritional and exercise interventions. All patients completed the program, but only 44 attended the reassessment after 12 months because of work reasons or lack of time or interest. RESULTS: Ergometry before and after cardiac rehabilitation showed significant differences in exercise tolerance time (5.2 ± 1.8 minutes vs 7.1 ± 2.1 minutes; P< .001), metabolic equivalents (6.5 ± 1.8 vs 8.8 ± 2.2; P< .001), and the Börg rating of perceived exertion scale (12 ± 1.8 points vs 13.7 ± 1.6 points; P= .005). At the end of the intervention program, significant improvements were seen in body weight (82.6 ± 15.2 kg vs 80.8 ± 14.3 kg; P< .001), waist circumference (100.3 ± 12.4 cm vs 98.0 ± 11.0 cm; P= .002), and levels of fasting glucose (126.5 ± 44.6 mmol/L vs 109.6 ± 24.8 mmol/L; P< .001), low-density lipoprotein cholesterol (2.7 ± 0.9 mmol/L vs 2.5 ± 0.8 mmol/L; P= .033), and C-reactive protein (5.1 ± 8.7 µg/mL vs 4.1 ± 2.6 µg/mL; P= .008), as well as in adherence to a healthy diet as estimated by the Trichopoulou questionnaire score (7.9 ± 2.3 vs 10.6 ± 1.5; P< .001). Twelve months later, however, many of these benefits had either remained stable or worsened. CONCLUSIONS: Cardiac rehabilitation is an appropriate program for the improvement of clinical and analytical variables, such as functional capacity, carbohydrate and lipid metabolism, anthropometric measures, and diet. However, 12 months later, many of these benefits either remained stable or worsened.

FES-cycling training in spinal cord injured patients.

Among the objectives of spinal cord injury (SCI) rehabilitation, (i) prevention of bony, muscular and joint trophism and (ii) limitation of spastic hypertone represent important goals to be achieved. The aim of this study is to use functional electrical stimulation (FES) to activate pedaling on cycle-ergometer and analyse effects of this technique for a rehabilitation training in SCI persons. Five spinal cord injured subjects were recruited and underwent a two months FES-cycling training. Our results show an increase of thigh muscular area and endurance after the FES-cycling training, without any increase of spasticity. This approach, which is being validated on a larger pool of patients, represents a potential tool for improving the rehabilitation outcome of complete and incomplete SCI persons.

Feasibility of interactive biking exercise system for telemanagement in elderly.

Inexpensive cycling equipment is widely available for home exercise however its use is hampered by lack of tools supporting real-time monitoring of cycling exercise in elderly and coordination with a clinical care team. To address these barriers, we developed a low-cost mobile system aimed at facilitating safe and effective home-based cycling exercise. The system used a miniature wireless 3-axis accelerometer that transmitted the cycling acceleration data to a tablet PC that was integrated with a multi-component disease management system. An exercise dashboard was presented to a patient allowing real-time graphical visualization of exercise progress. The system was programmed to alert patients when exercise intensity exceeded the levels recommended by the patient care providers and to exchange information with a central server. The feasibility of the system was assessed by testing the accuracy of cycling speed monitoring and reliability of alerts generated by the system. Our results demonstrated high validity of the system both for upper and lower extremity exercise monitoring as well as reliable data transmission between home unit and central server.

Comprehensive assessment of biventricular function and aortic stiffness in athletes with different forms of training by three-dimensional echocardiography and strain imaging.

AIMS: Previous studies have shown distinct models of cardiac adaptations to the training in master athletes and different effects of endurance and strength-training on cardiovascular function. We attempted to assess left-ventricular (LV) function, aortic (Ao) function, and right-ventricular (RV) function in athletes with different forms of training by using three-dimensional (3D) echocardiography, tissue Doppler imaging (TDI) and speckle-tracking imaging (STI). METHODS AND RESULTS: We examined 35 male marathon runners (endurance-trained athletes, ETA), 35 powerlifting athletes (strength-trained athletes, STA), 35 martial arts athletes (mixed-trained athletes, MTA), and 35 sedentary untrained healthy men (controls, CTR). Two-dimensional and three-dimensional echocardiography were performed for the assessment of LV and RV systolic/diastolic function. LV and RV longitudinal strain (LS) and LV torsion (LVtor) were determined using STI (EchoPAC BT11, GE-Ultrasound). Maximum velocity of systolic wall expansion peaks (AoSvel) was determined using TDI. ETA experienced LV eccentric hypertrophy with increased 3D LV end-diastolic volume and mass and significant increase in peak systolic apical rotation and LVtor. In all groups of athletes, RV-LS was reduced at rest and improved after exercise. AoSvel was significantly increased in ETA and MTA and significantly decreased in STA compared with CTR. There were good correlations between LV remodelling and aortic stiffness values. Multivariate analysis showed aortic wall velocities to be independently related to LV mass index. CONCLUSION: In strength-trained, endurance-trained, and mixed-trained athletes, ventricular and vascular response assessed by 3DE, TDI, and STI underlies different adaptations of LV, RV, and aortic indexes.

Lower-extremity functional electrical stimulation decreases platelet aggregation and blood coagulation in persons with chronic spinal cord injury: a pilot study.

BACKGROUND: Individuals with spinal cord injury (SCI) develop premature cardiovascular disease. Regular exercise reduces the incidence and symptoms of cardiovascular disease in able-bodied individuals; these salutary effects of exercise have not been documented in persons with SCI. OBJECTIVE: To evaluate the effects of functional electrical stimulation leg cycle ergometry (FES-LCE) exercise training on platelet aggregation and blood coagulation in persons with SCI. PARTICIPANTS: Subjects (n=14) with stable chronic (>1 year) paraplegia (T1-T10) or tetraplegia (C4-C8). METHODS: Blood samples were collected before and after the first and eighth sessions (2 sessions per week for 4 weeks) of FES exercise. RESULTS: Platelet aggregation was inhibited by 20% after the first session and by 40% (P < 0.001) after the eighth session. Thrombin activity was unchanged after the first session (10.7 +/- 0.85 s to 10.43 +/- 0.56 s) and decreased after the eighth session (12.5 +/- 1.98 s to 11.1 +/- 1.7 s; P < 0.0003). Antithrombin III activity increased after the first (103.8% +/- 8.9% to 110% +/- 6.9%; P < 0.0008) and eighth sessions (107.8% +/- 12.1% to 120.4% +/- 13.1%; P < 0.0001). Cyclic adenosine monophosphate increased after the first (9.9% + 2.5% to 15.8% +/- 3%; P < 0.001) and eighth sessions (17.8% +/- 4.2% to 36.5% +/- 7.6%; P < 0.0001). After the eighth session, factors V and X increased significantly (88% +/- 27% to 103% +/- 23%, P < 0.0001; 100% +/- 40% to 105% +/- 7%, P < 0.01, respectively); factors VII and VIII and fibrinogen did not change significantly. A significant reduction in platelet activation/aggregation was demonstrated in response to FES-LCE. The decrease in thrombin level was caused by the simultaneous increase in antithrombin activity. CONCLUSION: These findings provide new insight into the potential protective effects of FES-LCE against the risk of cardiovascular disease.

Response to functional electrical stimulation cycling in women with spinal cord injuries using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography: a case series.

BACKGROUND: Loss of bone mass is common after spinal cord injury (SCI). One rehabilitation modality that has shown some promise for maintaining bone health is the functional electrical stimulation (FES) cycle ergometer. Although there has been some research investigating bone health and FES cycle ergometry, few have provided a detailed description of the changes that can occur in bone mass and soft-tissue mass. OBJECTIVE: To use 2 types of bone imaging, peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA), to provide a detailed description of bone and soft-tissue response to FES cycle ergometry training in women with SCI. STUDY DESIGN: Case series; a 6-month program of FES cycle ergometry for women with chronic motor complete (n = 2) and incomplete (n = 1) SCI. SETTING: Outpatient rehabilitation center in Canada. METHODS: Three women participated in a thrice weekly 6-month exercise program of FES cycle ergometry. We used DXA (lower extremity) and pQCT at the midshaft (50%) and distal (5%) sites of the tibia to assess bone density and soft-tissue mass before and after the exercise program. RESULTS: There was an increase or maintenance in bone mineral density by DXA and pQCT in the lower extremity for all 3 participants. Muscle mass by DXA increased in the lower extremity in 2 participants. CONCLUSION: In this case series, we note a positive response in bone mass and soft-tissue mass in the lower extremity after a 6-month FES cycle ergometry program.

The effects of functional electrical stimulation leg cycle ergometry training on arterial compliance in individuals with spinal cord injury.

STUDY DESIGN: A prospective intervention of functional electrical stimulation leg cycle ergometry (FES-LCE) of four women with spinal cord injury (SCI). OBJECTIVE: To evaluate the effect of FES-LCE training on arterial compliance in individuals with chronic SCI of traumatic origin. SETTING: Tertiary rehabilitation center in Canada. METHODS: Large and small artery compliance were measured at the radial artery before and after a 3-month training program using FES-LCE. RESULTS: There was no significant change in large artery compliance after FES-LCE (16.0+/-4.2 to 16.8+/-6.1 ml mm Hg(-1) x 10, P=NS). There was a marked (63%) increase in small artery compliance after the FES training program (4.2+/-1.8 to 6.9+/-3.2 ml mm Hg(-1) x 100, P<0.05). CONCLUSION: It appears that FES-LCE is effective in improving small artery compliance in females with SCI.

Eficacia de la periodización del entrenamiento sobre la potencia máxima / Efficacy of periodized programson power training

El objetivo de este artículo es comparar la eficacia de los programas periodizados respecto a los no periodizados durante 5 semanas de entrenamiento en participantes físicamente activos con la intención de mejorar la potencia máxima de ejecución en el ejercicio de press de banca. 22 sujetos participaron en la investigación divididos en dos grupos, grupo 1(n=9, 2 mujeres y 7 hombres, edad 21.6 ± 1.1 años) cuyo tratamiento era un programa de entrenamiento no periodizado y grupo 2 (n=13, 3 mujeres y 10 hombres, edad 21.8 ± 1.4 años) con un tratamiento de programa de entrenamiento periodizado. El modelo no periodizado realizó 5 series de 6 repeticiones 2 veces/sem. durante 5 semanas, reevaluando la máxima potencia a las 2,5 semanas. El modelo periodizado se realizaron en la 1ª semana: 5 series de6 repeticiones; 2ª semana: 4x5; 3ª sem: 5x7; 4ª sem.: 5x8; 5ª sem.: 4x6, reevaluando la potencia a la mitad del estudio. El volumen y la intensidad total fueron igualados. Los resultados muestran como la potencia en la medición intermedia aumentó significativamente (p<0.05) un 13,26% respecto a la medición pretest en el modelo periodizado, mientras que en el no periodizado el incremento porcentual significativo fue de un 19,83%. En la medición final respecto a la intermedia la potencia disminuyó significativamente (p<0.05) un 10,21% en el modelo no periodizado. Concluimos que no existen diferencias significativas en las ganancias de potencia máxima entre ambos grupos, estimando asimismo que los resultados en sujetos no entrenados muestran limitaciones en la aplicabilidad de éstos a deportistas altamente entrenados (AU)

Periodization is one of the most important concepts in training. The purpose of this study was to compare periodized programs (PG) and non periodized programs (NPG) for gains maximal power in bench press. 22 subjects (sport sciences students) were randomly assigned to non periodized program (n=9; 2females and 7males; age 21.6 ± 1.1 years) or periodized program (n=13, 3 females; 10 males)age 21.8 ± 1.4 years). The non periodized program performed 5set of6 repetitions 2 days per week during 5 weeks changing the maximal power every 2,5 weeks. The periodized program performed (1st week: 5sets x 6 rept.;2nd week: 4x5;3th week: 5x7; 4 week:5x8; 5 week:4x6) changing the maximal power every 2,5 weeks. Volume and intensity were equated for each training program. After the end of the training programs, a testing session was performed to obtain the maximal power in bench press exercise. PG and NPG increased(p<.05) the maximal power after 2.5 training weeks (15.3% and 24.7%, respectively), without significant differences between groups. However, in the 2.5 next weeks, the maximal power increased 2.9% in PG, although this increase was not significant, while a decrease (10.2%; p<.05) in the maximal power happened in the NPG. PG and NPG increased(p <.05) the maximal power after 5 training weeks (18.6% and 11.9%, respectively), without significant differences between groups. In conclusion, so much a periodized training program like one non periodized training program producedim provements in the maximal power in bench press exercise in these participants, without significant differences between groups. Anyway, the results obtained in this type of subjects showed limitations in the applicability to highly trained sportsmen (AU)

Fuzzy logic control of FES rowing exercise in paraplegia.

An indoor personal rowing machine (Concept 2 Inc., Morrisville, VT) has been modified for functional electrical stimulation assisted rowing exercise in paraplegia. To successfully perform the rowing maneuver, the voluntarily controlled upper body movements must be coordinated with the movements of the electrically stimulated paralyzed legs. To achieve such coordination, an automatic controller was developed that employs two levels of hierarchy. A high level finite state controller identifies the state or phase of the rowing motion and activates a low-level state-dedicated fuzzy logic controller (FLC) to deliver the electrical stimulation to the paralyzed leg muscles. A pilot study with participation of two paraplegic volunteers showed that FLC spent less muscle energy, and produced smoother rowing maneuvers than the existing On-Off constant-level stimulation controller.

New algorithm to control a cycle ergometer using electrical stimulation.

Data were collected from four male subjects to determine the relationships between load, speed and muscle use during cycle ergometry. These data were then used to construct equations to govern the stimulation of muscle in paralysed individuals, during cycle ergometry induced by functional electrical stimulation (FES) of the quadriceps, gluteus maximus and hamstring muscles. The algorithm was tested on four subjects who were paralysed owing to a complete spinal cord injury between T4 and T11. Using the multivariate equation, the control of movement was improved, and work was accomplished that was double (2940 Nm min(-1) compared with 5880 Nm min(-1)) that of traditional FES cycle ergometry, when muscle stimulation was also controlled by electrical stimulation. Stress on the body, assessed by cardiac output, was increased almost two-fold during maximum work with the new algorithm (81 min(-1) compared with 15 l min(-1) with the new algorithm). These data support the concept that the limitation to workload that a person can achieve on FES cycle ergometry is in the control equations and not in the paralysed muscle.

Development of an indoor rowing machine with manual FES controller for total body exercise in paraplegia.

Concept 2 indoor rowing machine (Concept 2 Inc., USA) was modified for functional electrical stimulation (FES) rowing exercise in paraplegia. A new seating system provides trunk stability and constrains the leg motion to the sagittal plane. A 4-channel electrical stimulator activates the quadriceps and hamstrings in Drive and Recovery phases of the rowing cycle, respectively. Two force-sensing resistors (FSR) on the handle measure the thumb press as the command signal to the electrical stimulator. Optical encoders measure the positions of the seat and handle during rowing. To synchronize the voluntarily controlled upper body movement with the FES controlled leg movement, a novel manual control system was developed. It uses the voluntary thumb presses to control the timing of the stimulation to the paralyzed leg muscles. The manual control system was intuitive and easy to learn and resulted in well-coordinated rowing. Evaluation of the modified rower by paraplegic volunteers showed that it is effective, safe, and affordable exercise alternative for paraplegics.

Effects of single trial of heart-rate biofeedback during ramp bicycling exercise.

We examined whether a single trial of heart-rate biofeedback was effective to attenuate heart-rate responses during ramp exercise despite a lack of biofeedback conditioning. 35 healthy women exercised in two trials while they tried to attenuate their heart rate by watching biofeedback signals or they only exercised without biofeedback signals (Control trial). 17 subjects were able to attenuate the heart rate during Biofeedback trial (Can group) whereas the remaining subjects were not (Cannot group). In the Can group, the magnitude of heart-rate attenuation in all exercise time was equivalent to 11+/-3% of the preexercise heart rate. Since the heart-rate reduction was similar to that achieved after the heart-rate biofeedback conditioning in previous studies, it is likely that the single trial of heart-rate biofeedback was effective for almost half the subjects to attenuate the heart-rate responses during ramp exercise.

Knee extension dynamometer: a new device for dynamic isokinetic magnetic resonance spectroscopy experiments.

In the present study we introduce a new device for exercise magnetic resonance spectroscopy (MRS). It operates in a standard whole-body scanner. Mechanical exertion unit allows maximal 10 degrees to 15 degrees short-arc knee extensions. The device operates hydraulically and is based on isokinetic movement. The force and work conducted are automatically controlled by the electronic control and computer unit. A small surface coil placed on the vastus medialis muscle allows the collection of spectra without interfering spectra from nearby resting muscles. The force used for the extensions can be followed simultaneously as a curve on the screen in the operator's room and the data is transferred to a personal computer for later analysis. Total work and fatigue percentage are also calculated by the device. It also allows the use of different isokinetic exercise protocols. The measurements of force proved reliable in repeat measurements using an isokinetic test device as a control. This device has been used clinically for over a year, is easy to operate, and offers reliable measurements. It is well suited to trials where muscle energy states versus time are followed since it allows noninvasive simultaneous quantification of muscle performance and collecting MRS spectra at rest, during exercise, and in the recovery phase.