Comparison of elliptical training, stationary cycling, treadmill walking and overground walking

Pedaling Asymmetry Reflected by Bilateral EMG Complexity in Chronic Stroke

This study examines pedaling asymmetry using the electromyogram (EMG) complexity of six bilateral lower limb muscles for chronic stroke survivors. Fifteen unilateral chronic stroke and twelve healthy participants joined passive and volitional recumbent pedaling tasks using a self-modified stationary bike with a constant speed of 25 revolutions per minute. The fuzzy approximate entropy (fApEn) was adopted in EMG complexity estimation. EMG complexity values of stroke participants during pedaling were smaller than those of healthy participants (p = 0.002). For chronic stroke participants, the complexity of paretic limbs was smaller than that of non-paretic limbs during the passive pedaling task (p = 0.005). Additionally, there was a significant correlation between clinical scores and the paretic EMG complexity during passive pedaling (p = 0.022, p = 0.028), indicating that the paretic EMG complexity during passive movement might serve as an indicator of stroke motor function status. This study suggests that EMG complexity is an appropriate quantitative tool for measuring neuromuscular characteristics in lower limb dynamic movement tasks for chronic stroke survivors.

Physiological, perceptual, and biomechanical differences between treadmill and overground walking in healthy adults: A systematic review and meta-analysis

This systematic review and meta-analysis aims to compare physiological, perceptual and biomechanical outcomes between walking on a treadmill and overground surfaces. Five databases (CINAHL, EMBASE, MEDLINE, SPORTDiscus, Web of Science) were searched until September 2022. Included studies needed to be a crossover design comparing biomechanical, physiological, or perceptual measures between motorised-treadmill and overground walking in healthy adults (18-65 years) walking at the same speed (<5% difference). The quality of studies were assessed using a modified Downs and Black Quality Index. Meta-analyses were performed to determine standardised mean difference ± 95% confidence intervals for all main outcome measures. Fifty-five studies were included with 1,005 participants. Relative oxygen consumption (standardised mean difference [95% confidence interval] 0.38 [0.14,0.63]) and cadence (0.22 [0.06,0.38]) are higher during treadmill walking. Whereas stride length (-0.36 [-0.62,-0.11]) and step length (-0.52 [-0.98,-0.06]) are lower during treadmill walking. Most kinetic variables are different between surfaces. The oxygen consumption, spatiotemporal and kinetic differences on the treadmill may be an attempt to increase stability due to the lack of control, discomfort and familiarity on the treadmill. Treadmill construction including surface stiffness and motor power are likely additional constraints that need to be considered and require investigation. This research was supported by an Australian Government Research Training Program (RTP) scholarship. Protocol registration is CRD42020208002 (PROSPERO International Prospective Register of Systematic Reviews) in October 2020.

The effectiveness of different aerobic exercises to improve pain intensity and disability in chronic low back pain patients: a systematic review

Background: Physical activity, including aerobic exercise, is highly recommended for chronic low back pain (CLBP) patients to improve pain intensity and functional disability. Objectives: To assess the effectiveness of different aerobic exercises to reduce pain intensity and functional disability in patients with CLBP. Methods: A computer-aided search was performed to find Randomised Controlled Trials (RCTs) that evaluated the effectiveness of different aerobic exercises in CLBP. Articles published between January 2007 to December 2020 were included in the review. Quality assessment using the PEDro scale, extraction of relevant information, and evaluation of outcomes were done by two reviewers independently. Results: A total of 17 studies were included that involved 1146 participants. Outcomes suggested that aerobic exercise combined with other interventions was more effective than aerobic exercise alone. Aerobic exercise with higher frequency (≥ 5 days/week) and longer duration (≥ 12 weeks) were effective to gain clinically significant (≥ 30%) improvements. Environment and using pedometer did not seem to influence the outcomes. Conclusions: Pain intensity and functional disability in CLBP patients can be minimized by prescribing aerobic exercise. However, to get better improvements, aerobic exercise should be done in combination with other interventions and at optimum frequency and duration. Further studies should emphasize examining the optimal doses and duration of different aerobic exercises.

Effects of cross-training on motor function and length of stay after total hip arthroplasty: A randomized controlled trial

BACKGROUND

There is no consensus about which training methods will give better early outcomes after total hip arthroplasty (THA).

OBJECTIVE

To investigate the short-term effects of cross trainer exercise on physical function and walking ability following THA.

METHODS

Fifty patients who underwent THA were randomly allocated into two groups. The intervention program was started 3 days after surgery. The main physical function results were pain, hip range of motion, knee extensor strength, single-leg stance time, and walking performance test. In addition, the number of days of requiring to walk and the length of hospital stay were recorded.

RESULTS

In the comparison between groups at discharge, the patients in the cross trainer group had significantly less hip pain while walking, improvement in knee extensor strength, increased single-leg stance time, as well as increased walking speed and stride length at discharge. The number of days required to walk and length of stay were also significantly lower in the intervention group.

CONCLUSIONS

Conclusions: Cross trainer exercise commencing 3 days postoperatively improves physical function and walking ability after THA.

Association of Core Muscle Endurance with Weekly Workout Time, Speed, and the Symmetry of Frontal Core Motion during Indoor Walking and Cycling

This study investigated the factors that influence core muscle endurance, i.e., the symmetry of frontal core motion during indoor walking and cycling, the symmetry of lateral core muscle endurance, the symmetry of the hip abductor strength, the weekly workout time and fast walking and cycling speeds, while controlling for gender. Seventy-nine healthy young adults participated in this study. In a regression analysis, the core muscle endurance time was the dependent variable. The independent variables were the symmetry of frontal core motion (measured using a wireless earbud sensor during walking and cycling), the symmetry of side plank time and of hip abductor strength, the weekly workout time and fast walking and cycling speeds. In the multiple regression analysis, weekly workout time, fast walking speed, symmetry of frontal core motion during fast cycling and symmetry of lateral side plank time predicted core muscle endurance (adjusted R2 = 0.42). Thus, clinicians and fitness personnel should consider the association of core muscle endurance with the symmetry of frontal core motion during cycling and the symmetry of side plank holding time, as well as with the weekly workout time and a fast walking speed, when designing core muscle exercise programmes.

Elliptical Trainer Redesign to Diversify Muscles Recruitment

This work aims to introduce simple-to-implement modifications to the elliptical trainer device to increase its utility with added new exercise options. The effectiveness of the introduced modifications was assessed on 51 subjects, with effectiveness representing the recruitment of a broader range of muscle groups with desired intensity levels. The improvements include a new in-phase mode, where bilateral body synchronization creates a skiing-like motion, and a variable range of motion through adjusting the stride length of a rotating-link mechanism.

The impact of these modifications on muscle recruitment was assessed by recording surface electromyogram (sEMG) from eleven major muscles while performing a total of six exercise routines. The routines have various combinations of mode and intensity to cover the traditional mechanism and the newly- introduced mechanism adjustments for comparative analysis.

The results have shown that increasing the stride length increases the demand on lower limbs muscles during the anti-phase mode while decreasing it on upper limb muscles. When comparing the two exercise modes, all muscle groups showed significantly higher activity in the in-phase mode except for thigh muscles (Hamstrings and Quadriceps). Hamstrings revealed significantly higher activity in the anti-phase mode, while Quadriceps showed no significantly different activity between the two modes.

The introduced design modifications are shown to diversify the demand on major skeletal muscles hence improving its functionality at low added cost. Furthermore, these results can be exploited to implement gradual physiotherapeutic rehabilitation plans targeting various muscle groups with desired intensity levels.

Is treadmill walking biomechanically comparable to overground walking? A systematic review

BACKGROUND

The equivalency of treadmill and overground walking has been investigated in a large number of studies. However, no systematic review has been performed on this topic.

RESEARCH QUESTION

The aim of this study was to compare the biomechanical, electromyographical and energy consumption outcomes of motorized treadmill and overground walking.

METHODS

Five databases, ScienceDirect, SpringerLink, Web of Science, PubMed, and Scopus, were searched until January 13, 2021. Studies written in English comparing lower limb biomechanics, electromyography and energy consumption during treadmill and overground walking in healthy young adults (20-40 years) were included.

RESULTS

Twenty-two studies (n = 409 participants) were included and evaluated via the Cochrane Collaboration's tool. These 22 studies showed that some kinematic (reduced pelvic ROM, maximum hip flexion angle for females, maximum knee flexion angle for males and cautious gait pattern), kinetic (sagittal plane joint moments: dorsiflexor moments, knee extensor moments and hip extensor moments and sagittal plane joint powers at the knee and hip joints, peak backwards, lateral and medial COP velocities and propulsive forces during late stance) and electromyographic (lower limbs muscles activities) outcome measures were significantly different for motorized treadmill and overground walking.

SIGNIFICANCE

Spatiotemporal, kinematic, kinetic, electromyographic and energy consumption outcome measures were largely comparable for motorized treadmill and overground walking. However, the differences in kinematic, kinetic and electromyographic parameters should be taken into consideration by clinicians, trainers, and researchers when working on new protocols related to patient rehabilitation, fitness rooms or research as to be as close as possible to the outcome measures of overground walking. The protocol registration number is CRD42021236335 (PROSPERO International Prospective Register of Systematic Reviews).

Cortico-muscular interaction to monitor the effects of neuromuscular electrical stimulation pedaling training in chronic stroke

Neuromuscular electrical stimulation (NMES) has been widely utilized in post-stroke motor restoration. However, its impact on the closed-loop sensorimotor control process remains largely unclear. This is the first study to investigate the directional changes in cortico-muscular interactions after repetitive rehabilitation training by measuring the noninvasive electroencephalogram (EEG) and electromyography (EMG) signals. In this study, 10 subjects with chronic stroke received 20 sessions of NMES-pedaling interventions, and each training session included three 10-min NMES-driven pedaling trials. In addition, pre- and post-intervention assessments of lower limb isometric contraction were conducted before and after the whole NMES-pedaling interventions. The EEG (128 channels) and EMG (3 bilateral lower limb sensors) signals were collected during the isometric contraction tasks for the paretic and non-paretic lower limbs. Both the cortico-muscular coherence (CMC) and generalized partial directed coherence (GPDC) values were analyzed between eight selected EEG channels in the central primary motor cortex and EMG channels. The results revealed significant clinical improvements. Additionally, rehabilitation training facilitated cortico-muscular interaction of the ipsilesional brain and paretic lower limbs (p = 0.004). Moreover, both the descending and ascending cortico-muscular pathways were altered after NMES-training (p = 0.001, p < 0.001). Therefore, the results implied potential applications of EEG-EMG in understanding neuromuscular changes during the post-stroke motor rehabilitation process.

Effects of cognitive workload on heart and locomotor rhythms coupling

Different physiological signals could be coupled under specific conditions, in some cases related to pathologies or reductions in system complexity. Cardiac-locomotor synchronization (CLS) has been one of the most investigating coupling. The influence of a cognitive task on walking was investigated in dual-task experiments, but how different cognitive tasks may influence CLS has poorly been investigated. Twenty healthy subjects performed a dual-task walking (coupled with verbal fluency vs calculation) on a treadmill at three different speeds (comfortable speed CS; fast-speed: CS + 2 km/h; slow-speed: CS-2 km/h) while cardiac and walking rhythms were recorded using surface electrodes and a triaxial accelerometer, respectively. According to previous studies, we found a cognitive-motor interference for which cognitive performance was affected by motor exercise, but not vice-versa. We found a CLS at the baseline condition, at fast speed in both cognitive tasks, while at comfortable speed only for the verbal fluency task. In conclusion, the cardiac and locomotor rhythms were not coupled at slow speed and at comfortable speed during subtraction task. Cognitive performances generally increased at faster speed, when cardiac locomotor coupling was stronger.

Comparison of plantar pressure profile of young adults during training on elliptical devices and overground walking: A pilot study

BACKGROUND

Elliptical training may offer advantages over other cardiorespiratory exercises for those requiring podiatric care, since its constant double-limb support diminishes recurring high-impact plantar forces while allowing exercise in a functional, upright posture. Unknown is the impact of distinct elliptical models, that can alter user's body mechanics, on potential variations in plantar pressure patterns.

PURPOSE

To compare plantar pressure variables while exercising on four ellipticals and walking.

METHODS

For this cross-sectional pilot study, plantar pressure data were recorded from ten young adults while exercising on four ellipticals (True, Octane, Life Fitness, SportsArt) and walking overground. One-way repeated measures ANOVA identified differences in heel, arch, and forefoot maximum force (MF), peak pressure (PP), and pressure-time integral (PTI).

RESULTS

MF was lower under the heel when exercising on all ellipticals compared with walking, with further differences detected between models. PP was lower on all three foot regions when exercising on all ellipticals compared with walking, except Octane under the arch, with differences detected between ellipticals under the heel. PTI was lower under the heel and arch when exercising on some of the ellipticals compared with walking, with differences again detected under the heel between models.

CONCLUSION

Plantar pressures were lower when exercising on the ellipticals compared with walking for most variables. Caution is recommended to which elliptical could be incorporated into therapeutic programs given that differences among models were detected under the heel.

Plane Dependent Subject-Specific Neuromuscular Training for Knee Rehabilitation

Knee injuries at risk of post-traumatic knee osteoarthritis (PTOA) and knee osteoarthritis (OA) are closely associated with knee transverse plane and/or frontal plane instability and excessive loading. However, most existing training and rehabilitation devices involve mainly movements in the sagittal plane. An offaxis elliptical training system was developed to train and evaluate neuromuscular control about the off-axes (knee varus/valgus and tibial rotation) as well as the main flexion/extension axis (sagittal movements). Effects of the offaxis elliptical training system in improving either transverse or frontal neuromuscular control depending on subjects' need (Pivoting group, Sliding group) were demonstrated through 6-week subject-specific neuromuscular training in subjects with knee injuries at risk of PTOA or medial knee osteoarthritis. The combined pivoting and sliding group, named as offxis group demonstrated significant reduction in pivoting instability, minimum pivoting angle, and sliding instability. The pivoting group showed more reduction in pivoting instability, maximum and minimum pivoting angle than the sliding group. On the other hand, the sliding group showed more reduction in sliding instability, maximum and minimum sliding distance than the pivoting group. Based on these findings, the offaxis elliptical trainer system can potentially be used as a therapeutic and research tool to train human subjects for plane-dependent improvements in their neuromuscular control during functional weight-bearing stepping movements.

Biomechanical Comparison of a New Dynamic Ankle Orthosis to a Standard Ankle-Foot Orthosis During Walking

Patients who sustain irreversible cartilage damage or joint instability from ankle injuries are likely to develop ankle osteoarthritis (OA). A dynamic ankle orthosis (DAO) was recently designed with the intent to offload the foot and ankle using a distractive force, allowing more natural sagittal and frontal plane ankle motion during gait. To evaluate its efficacy, this study compared ankle joint kinematics and plantar pressures among the DAO, standard double upright ankle-foot orthosis (DUAFO), and a nonorthosis control (CON) condition in healthy adults during walking. Ten healthy subjects (26 ± 3.8 yr; 69.6 ± 12.7 kg; and 1.69 ± 0.07 m) walked on a treadmill at 1.4 m/s in three orthosis conditions: CON, DAO, and DUAFO. Ankle kinematics were assessed using a three-dimensional (3D) motion capture system and in-shoe plantar pressures were measured for seven areas of the foot. DAO reduced hallux peak plantar pressures (PPs) compared to CON and DUAFO. PPs under toes 2-5 were smaller in DAO than DUAFO, but greater in DUAFO compared to CON. Early stance peak plantarflexion (PF) angular velocity was smaller in DAO compared to CON and DUAFO. Eversion (EV) ROM was much smaller in DUAFO compared to CON and DAO. Early stance peak eversion angular velocity was smaller in DAO and much smaller in DUAFO compared to CON. This study demonstrates the capacity of the DAO to provide offloading during ambulation without greatly affecting kinematic parameters including frontal plane ankle motion compared to CON. Future work will assess the effectiveness of the DAO in a clinical osteoarthritic population.

Using Body-Worn Sensors to Detect Changes in Balance and Mobility After Acute Aerobic Exercise in Adults with Multiple Sclerosis

Background

Current mobility and functional assessments do not capture the subtle changes in balance and gait that may predispose people with multiple sclerosis (MS) to falling. The purpose of this study was to use clinical and instrumented measures to examine the effects of an acute bout of aerobic exercise on balance and gait in individuals with MS.

Methods

Ten adults with MS performed 15 minutes of moderate-intensity recumbent cycling or 15 minutes of rest. Exercise and rest visit order was randomized and separated by 1 week. Balance and mobility were assessed before, immediately after, and 2 hours after each test condition.

Results

There were no significant differences across measurement periods for Timed 25-Foot Walk test times or Brief Balance Evaluation Systems Test scores. Significant improvements in mean sway radius and sway velocity when standing on foam and in percentage of stance stride time variability were found immediately after exercise compared with immediately after rest.

Conclusions

This study lends further evidence that individuals with MS can safely engage in single bouts of aerobic exercise without detrimental short-term effects on function and may actually receive some short-term benefit regarding standing postural sway and gait variability. Future research should examine the dose-dependent relationship of varying types, intensities, or timing of exercise necessary to elicit short-term functional benefit and long-term health outcomes.

Pathway-specific modulatory effects of neuromuscular electrical stimulation during pedaling in chronic stroke survivors

Background

Neuromuscular electrical stimulation (NMES) is extensively used in stroke motor rehabilitation. How it promotes motor recovery remains only partially understood. NMES could change muscular properties, produce altered sensory inputs, and modulate fluctuations of cortical activities; but the potential contribution from cortico-muscular couplings during NMES synchronized with dynamic movement has rarely been discussed.

Method

We investigated cortico-muscular interactions during passive, active, and NMES rhythmic pedaling in healthy subjects and chronic stroke survivors. EEG (128 channels), EMG (4 unilateral lower limb muscles) and movement parameters were measured during 3 sessions of constant-speed pedaling. Sensory-level NMES (20 mA) was applied to the muscles, and cyclic stimulation patterns were synchronized with the EMG during pedaling cycles. Adaptive mixture independent component analysis was utilized to determine the movement-related electro-cortical sources and the source dipole clusters. A directed cortico-muscular coupling analysis was conducted between representative source clusters and the EMGs using generalized partial directed coherence (GPDC). The bidirectional GPDC was compared across muscles and pedaling sessions for post-stroke and healthy subjects.

Results

Directed cortico-muscular coupling of NMES cycling was more similar to that of active pedaling than to that of passive pedaling for the tested muscles. For healthy subjects, sensory-level NMES could modulate GPDC of both ascending and descending pathways. Whereas for stroke survivors, NMES could modulate GPDC of only the ascending pathways.

Conclusions

By clarifying how NMES influences neuromuscular control during pedaling in healthy and post-stroke subjects, our results indicate the potential limitation of sensory-level NMES in promoting sensorimotor recovery in chronic stroke survivors.

Real-Time Three-Dimensional Knee Moment Estimation in Knee Osteoarthritis: Toward Biodynamic Knee Osteoarthritis Evaluation and Training

We investigated differences in knee kinetic variables (external knee adduction, flexion, internal rotation moments, and impulses) between patients with knee osteoarthritis (KOA) and healthy controls during stepping on a custom elliptical trainer; and searched knee kinetic variable candidates for real-time biofeedback and for complementing diagnosis/evaluation on the elliptical trainer based on the knee kinetic variables' associations with the knee injury and osteoarthritis outcome score (KOOS). Furthermore, we explored potential gait re-training strategies on the elliptical trainer by investigating the knee kinetic variables' associations with 3-D ankle angles. The knee kinetic variables and ankle angles were determined in real-time in a patient group of 10 patients with KOA and an age-and sex-matched control group of 10 healthy subjects. The mean peak external knee adduction moment of the patient group was 47% higher than that of the control group. The KOOS-Sports and Recreational Activities and KOOS-Pain scores were found to be significantly associated with the knee kinetic variables. All the ankle angles were associated with the knee kinetic variables. The findings support the use of the knee kinetic variables on the elliptical trainer to complement KOA diagnosis quantitatively and provide potential real-time KOA gait re-training strategies/guides.

Walking speed and spatiotemporal step mean measures are reliable during feedback-controlled treadmill walking; however, spatiotemporal step variability is not reliable

The purpose of the study was to compare the effects of a feedback-controlled treadmill (FeedbackTM) to a traditional fixed-speed treadmill (FixedTM) on spatiotemporal gait means, variability, and dynamics. The study also examined inter-session reliability when using the FeedbackTM. Ten young adults walked on the FeedbackTM for a 5-minute familiarization followed by a 16-minute experimental trial. They returned within one week and completed a 5-minute familiarization followed by a 16-minute experimental trial each for FeedbackTM and FixedTM conditions. Mean walking speed and step time, length, width, and speed means and coefficient of variation were calculated from all experimental conditions. Step time, length, width, and speed gait dynamics were analyzed using detrended fluctuation analysis. Mean differences between experimental trials were determined using ANOVAs and reliability between FeedbackTM sessions was determined by intraclass correlation coefficient. No difference was found in mean walking speed nor spatiotemporal variables, with the exception of step width, between the experimental trials. All mean spatiotemporal variables demonstrated good to excellent reliability between sessions, while coefficient of variation was not reliable. Gait dynamics of step time, length, width, and speed were significantly more persistent during the FeedbackTM condition compared to FixedTM, especially step speed. However, gait dynamics demonstrated fair to poor reliability between FeedbackTM sessions. When walking on the FeedbackTM, users maintain a consistent set point, yet the gait dynamics around the mean are different when compared to walking on a FixedTM. In addition, spatiotemporal gait dynamics and variability may not be consistent across separate days when using the FeedbackTM.

A Comparison of Both Motorized and Nonmotorized Treadmill Gait Kinematics to Overground Locomotion

Context: Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. Objective: The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. Design: Crossover study. Setting: A university research laboratory. Patients: A total of 20 healthy adults (10 women) participated in the study. Intervention: Each participant performed self-selected walking and running OG, and on both an MT and NMT. Main Outcome Measure: Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. Results: The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, −3.1°, and −5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). Conclusions: These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.

Effects of pelvic range of motion and lower limb muscle activation pattern on over-ground and treadmill walking at the identical speed in healthy adults

[Purpose] Many studies have compared over-ground and treadmill walking, but the biomechanical relationship between the two gait modes is unclear. The aim of this study was to analyze differences in pelvic range of motion and lower limb muscles activity during over-ground and treadmill walking in healthy adults. Moreover, we aimed to analyze differences according to gender. [Subjects and Methods] Twenty-three healthy adults (9 men, 14 women) between 25 and 35 years of age walked at the identical speed for 30 seconds each in two difference gait modes. The pelvic range of motion were obtained by using three-axis accelerometer and lower limb muscle activation data were obtained by using wireless surface EMG. [Results] The results showed that pelvic obliquity showed a greater angular range of women than men, and the pelvic rotation decreased more in treadmill walking than over-ground walking. In the muscles activity, vastus lateralis and tibialis anterior increased, and gastrocnemius medialis decreased in treadmill walking than over-ground walking. [Conclusion] We conclude that treadmill walking reduces the range of motion of the pelvic and increases lower limb muscles activity therefore, when using treadmill for the purpose of rehabilitation at the clinic, consider this difference.

Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness

The maximum oxygen uptake (V̇O2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to determine V̇O2 max in young healthy male adults. Thirty-two young healthy male adults (32 males; age range: 20-35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (CE) to directly obtain measured V̇O2 max. Subjects then completed the progressive multistage test on the RSE beginning at 50W and including additional stages of 70, 90, 110, 130, and 150W, and the RSE YMCA submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. A metabolic equation was derived from the RSE multistage exercise test to predict oxygen consumption (V̇O2) from power output (W) during the submaximal exercise test (V̇O2 (mL·min-1 )=12.4 ×W(watts)+3.5 mL·kg-1·min-1×M+160mL·min-1, R2= 0.91, standard error of the estimate (SEE) = 134.8mL·min-1). A high correlation was observed between the RSE YMCA estimated V̇O2 max and the CE measured V̇O2 max (r=0.87). The mean difference between estimated and measured V̇O2 max was 2.5 mL·kg-1·min-1, with an SEE of 3.55 mL·kg-1·min-1. The data suggest that the RSE YMCA submaximal exercise test is valid for predicting V̇O2 max in young healthy male adults. The findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting V̇O2 max. The newly-designed RSE may be potentially further developed as an alternative ergometer for assessing cardiorespiratory fitness and the promotion of personalized health interventions for health care professionals.

Lower limb muscular activity during walking at different speeds: Over-ground versus treadmill walking: A voluntary response evaluation

OBJECTIVE

To evaluate the overall lower limb muscular activity pattern during treadmill walking compared to over-ground walking.

METHODOLOGY

The study was conducted on 25 healthy young females. Surface electromyography was recorded from gastrocnemius, hamstrings, vasti and gluteus medius muscles during walking over-ground and treadmill at 3 different speeds (comfortable, slow and fast). The pattern of muscle activity was compared between two walking conditions at different speeds by the voluntary response index method. Voluntary response index is composed of two numeric values: magnitude which represents the strength of overall muscular activity, and similarity index which represents the resemblance of overall muscle activity.

RESULTS

The main effect of walking conditions and speed as well as their interaction effect (P < 0.001) on magnitude of muscle activity were significant but not for similarity index.

CONCLUSIONS

The pattern of muscular activity during walking on treadmill and over-ground was similar but walking on treadmill induced higher muscular activity in the lower limb musculature.

Task-Specific and Functional Effects of Speed-Focused Elliptical or Motor-Assisted Cycle Training in Children With Bilateral Cerebral Palsy: Randomized Clinical Trial

BACKGROUND

Locomotor training using treadmills or robotic devices is commonly utilized to improve gait in cerebral palsy (CP); however, effects are inconsistent and fail to exceed those of equally intense alternatives. Possible limitations of existing devices include fixed nonvariable rhythm and too much limb or body weight assistance.

OBJECTIVE

To quantify and compare effectiveness of a motor-assisted cycle and a novel alternative, an elliptical, in CP to improve interlimb reciprocal coordination through intensive speed-focused leg training.

METHODS

A total of 27 children with bilateral CP, 5 to 17 years old, were randomized to 12 weeks of 20 minutes, 5 days per week home-based training (elliptical = 14; cycle = 13) at a minimum of 40 revolutions per minute, with resistance added when speed target was achieved. Primary outcomes were self-selected and fastest voluntary cadence on the devices and gait speed. Secondary outcomes included knee muscle strength, and selective control and functional mobility measures.

RESULTS

Cadence on trained but not nontrained devices increased, demonstrating task specificity of training and increased exercise capability. Mean gait speed did not increase in either group, nor did parent-reported functional mobility. Knee extensor strength increased in both. An interaction between group and time was seen in selective control with scores slightly increasing for the elliptical and decreasing for the cycle, possibly related to tighter limb coupling with cycling.

CONCLUSIONS

Task-specific effects were similarly positive across groups, but no transfer was seen to gait or function. Training dose was low (≤20 hours) compared with intensive upper-limb training recommendations and may be insufficient to produce appreciable clinical change.

Frequency analysis of the center of pressure in tandem stance in community-dwelling elderly

[Purpose] The present study aimed to clarify the effects of balance control on the pronation and supination movements of the talocrural joint in community-dwelling elderly women by conducting a frequency analysis of the center of pressure during tandem stance. [Subjects and Methods] The study participants were 18 subjects who maintained tandem stance for 20 s and 11 who had difficulty maintaining tandem stance for 20 s. The frequency-power spectra were computed and classified into three frequency bands. Each power spectral value was divided by the sum of the power spectral values to obtain the %power. [Results] Significant differences in high-frequency band %power value for the center of pressure in both the mediolateral and anteroposterior components were evident between the groups. [Conclusion] A markedly significant difference was observed, particularly in high frequency band %power, depending on balance control. The present findings indicated that elderly participants with diminished balance control had difficulty with rapid adjustment centered on the ankles, suggesting that rapid joint movement involving interlimb coordination centered on the ankles is required to maintain tandem stance.

COMPARISON OF TRUNK AND LOWER EXTREMITY MUSCLE ACTIVITY AMONG FOUR STATIONARY EQUIPMENT DEVICES: UPRIGHT BIKE, RECUMBENT BIKE, TREADMILL, AND ELLIPTIGO®

BACKGROUND

Stationary equipment devices are often used to improve fitness. The ElliptiGO® was recently developed that blends the elements of an elliptical trainer and bicycle, allowing reciprocal lower limb pedaling in an upright position. However, it is unknown whether the muscle activity used for the ElliptiGO® is similar to walking or cycling. To date, there is no information comparing muscle activity for exercise on the treadmill, stationary upright and recumbent bikes, and the ElliptiGO®.

PURPOSE/HYPOTHESIS

The purpose of this study was to assess trunk and lower extremity muscle activity among treadmill walking, cycling (recumbent and upright) and the ElliptiGO® cycling. It was hypothesized that the ElliptiGO® and treadmill would elicit similar electromyographic muscle activity responses compared to the stationary bike and recumbent bike during an exercise session.

STUDY DESIGN

Cohort, repeated measures.

METHODS

Twelve recreationally active volunteers participated in the study and were assigned a random order of exercise for each of the four devices (ElliptiGO®, stationary upright cycle ergometer, recumbent ergometer, and a treadmill). Two-dimensional video was used to monitor the start and stop of exercise and surface electromyography (SEMG) were used to assess muscle activity during two minutes of cycling or treadmill walking at 40-50% heart rate reserve (HRR). Eight muscles on the dominant limb were used for analysis: gluteus maximus (Gmax), gluteus medius (Gmed), biceps femoris (BF), lateral head of the gastrocnemius (LG), tibialis anterior (TA), rectus femoris (RF). Two trunk muscles were assessed on the same side; lumbar erector spinae at L3-4 level (LES) and rectus abdominus (RA). Maximal voluntary isometric contractions (MVIC) were determined for each muscle and SEMG data were expressed as %MVIC in order to normalize outputs.

RESULTS

The %MVIC for RF during ElliptiGO® cycling was higher than recumbent cycling. The LG muscle activity was highest during upright cycling. The TA was higher during walking compared to recumbent cycling and ElliptiGO® cycling. No differences were found among the the LES and remaining lower limb musculature across devices.

CONCLUSION

ElliptiGO® cycling was found to elicit sufficient muscle activity to provide a strengthening stimulus for the RF muscle. The LES, RA, Gmax, Gmed, and BF activity were similar across all devices and ranged from low to moderate strength levels of muscle activation. The information gained from this study may assist clinicians in developing low to moderate strengthening exercise protocols when using these four devices.

LEVEL OF EVIDENCE

3.

The effect of step climbing exercise on balance and step length in chronic stroke patients

[Purpose] The objective of this study was to examine the effect of step climbing exercise on the walking ability of stroke patients. [Subjects and Methods] Among hospitalized stroke patients, 24 were selected based on the study criteria and randomly divided into two groups: an experimental group (12 patients) and a control group (12 patients). The patients in both groups participated in 15-minute exercise sessions three times a week for eight weeks. To analyze the effect of the exercise, muscle strength, the Timed Up and Go test, and step length were measured before and after the exercise. [Results] step climbing exercise improved the muscle strength in the lower limbs of the stroke patients, as well as their Timed Up and Go results and step lengths. [Conclusion] The effects were similar to a stair gait exercise, and thus, step climbing may be more broadly applied to the treatment of stroke patients.

Effects of Off-Axis Elliptical Training on Reducing Pain and Improving Knee Function in Individuals With Patellofemoral Pain

OBJECTIVE

To examine whether an off-axis elliptical training program reduces pain and improves knee function in individuals with patellofemoral pain (PFP).

DESIGN

Controlled laboratory study, pretest-posttest.

SETTING

University rehabilitation center.

PARTICIPANTS

Twelve adult subjects with PFP.

INTERVENTIONS

Subjects with PFP completed an exercise program consisting of 18 sessions of lower extremity off-axis training using a custom-made elliptical trainer that allows frontal plane sliding and transverse plane pivoting of the footplates.

MAIN OUTCOME MEASURES

Changes in knee pain and function posttraining and 6 weeks after training were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) scores. Lower extremity off-axis control was assessed by pivoting and sliding instability, calculated as the root mean square (RMS) of the footplate pivoting angle and sliding distance during elliptical exercise. Subjects' single-leg hop distance and proprioception in detecting lower extremity pivoting motion were also evaluated.

RESULTS

Subjects reported significantly greater KOOS and IKDC scores (increased by 12-18 points) and hop distance (increased by 0.2 m) after training. A significant decrease in the pivoting and sliding RMS was also observed after training. Additionally, subjects with PFP demonstrated improved pivoting proprioception when tested under a minimum weight-bearing position.

CONCLUSIONS

An off-axis elliptical training program was effective in enhancing lower extremity neuromuscular control on the frontal and transverse planes, reducing pain, and improving knee function in persons with PFP.

CLINICAL RELEVANCE

This study provides a novel intervention approach to enhance the control of the frontal and transverse plane motions of the lower extremities during functional weight-bearing activities. This novel off-axis elliptical training may be incorporated with other common treatment options currently available for PFP to augment the effects of musculoskeletal rehabilitation for the PFP population.

Lower Limb Joint Angular Position and Muscle Activity During Elliptical Exercise in Healthy Young Men

The purpose of this study was to compare lower extremity joint angular position and muscle activity during elliptical exercise using different foot positions and also during exercise on a lateral elliptical trainer. Sixteen men exercised on a lateral elliptical and on a standard elliptical trainer using straight foot position, increased toe-out angle, and a wide step. Motion capture and electromyography systems were used to obtain 3D lower extremity joint kinematics and muscle activity, respectively. The lateral trainer produced greater sagittal and frontal plane knee range of motion (ROM), greater peak knee flexion and extension, and higher vastus medialis activation compared with other conditions (P < .05). Toe-out and wide step produced the greatest and smallest peak knee adduction angles, respectively (P < .05). The lateral trainer produced greater sagittal and frontal plane hip ROM and greater peak hip extension and flexion compared with all other conditions (P < .05). Toe-out angle produced the largest peak hip external rotation angle and lowest gluteus muscle activation (P < .05). Findings from this study indicate that standard elliptical exercise with wide step may place the knee joint in a desirable frontal plane angular position to reduce medial knee loads, and that lateral elliptical exercise could help improve quadriceps strength but could also lead to larger knee contact forces.

Real-time tracking of knee adduction moment in patients with knee osteoarthritis

BACKGROUND

The external knee adduction moment (EKAM) is closely associated with the presence, progression, and severity of knee osteoarthritis (OA). However, there is a lack of convenient and practical method to estimate and track in real-time the EKAM of patients with knee OA for clinical evaluation and gait training, especially outside of gait laboratories.

NEW METHOD

A real-time EKAM estimation method was developed and applied to track and investigate the EKAM and other knee moments during stepping on an elliptical trainer in both healthy subjects and a patient with knee OA.

RESULTS

Substantial changes were observed in the EKAM and other knee moments during stepping in the patient with knee OA.

COMPARISON WITH EXISTING METHOD(S)

This is the first study to develop and test feasibility of real-time tracking method of the EKAM on patients with knee OA using 3-D inverse dynamics.

CONCLUSIONS

The study provides us an accurate and practical method to evaluate in real-time the critical EKAM associated with knee OA, which is expected to help us to diagnose and evaluate patients with knee OA and provide the patients with real-time EKAM feedback rehabilitation training.

Clinical Implications of Changing Parameters on an Elliptical Trainer

BACKGROUND

Specific weightbearing instructions continue to be a part of routine orthopaedic clinical practice on an injured or postoperative extremity. Researchers and clinicians have struggled to define the best weightbearing strategies to maximize clinical outcomes.

PURPOSE

To investigate the average percentage body weight (APBW) values, weightbearing distribution percentages (WBDP), and cadence values on the entire foot, hindfoot, and forefoot during changing resistance and incline on an elliptical trainer, as well as to suggest clinical implications.

STUDY DESIGN

Descriptive laboratory study.

METHODS

An original research study was performed consisting of 30 asymptomatic subjects (mean age, 29.54 ± 12.64 years; range, 21-69 years). The protocol included 3 consecutive tests of changing resistance and incline within a speed range of 70 to 95 steps/min. The SmartStep weightbearing gait analysis system was utilized to measure the values.

RESULTS

The APBW values for the entire foot ranged between 70% and 81%, the hindfoot values were between 27% and 57%, and the forefoot values between 42% and 70%. With regard to WBDP, the forefoot remained planted on the pedal (stance phase) 2 to 3 times more as compared with the hindfoot raise in the swing phase.

CONCLUSION

The study findings highlight the fact that elliptical training significantly reduces weightbearing in the hindfoot, forefoot, and entire foot even at higher levels of resistance and incline.

CLINICAL RELEVANCE

Weightbearing on the hindfoot consistently displayed the lowest weightbearing values. Orthopaedic surgeons, now equipped with accurate weightbearing data, may recommend using the elliptical trainer as a weightbearing exercise early on following certain bony or soft tissue pathologies and lower limb surgical procedures.

Real-time knee adduction moment feedback training using an elliptical trainer

The external knee adduction moment (EKAM) is associated with knee osteoarthritis (OA) in many aspects including presence, progression, and severity of knee OA. Despite of its importance, there is a lack of EKAM estimation methods that can provide patients with knee OA real-time EKAM biofeedback for training and clinical evaluations without using a motion analysis laboratory. A practical real-time EKAM estimation method, which utilizes kinematics measured by a simple six degree-of-freedom goniometer and kinetics measured by a multi-axis force sensor underneath the foot, was developed to provide real-time feedback of the EKAM to the patients during stepping on an elliptical trainer, which can potentially be used to control and alter the EKAM. High reliability (ICC(2,1): 0.9580) of the real-time EKAM estimation method was verified through stepping trials of seven subjects without musculoskeletal disorders. Combined with advantages of elliptical trainers including functional weight-bearing stepping and mitigation of impulsive forces, the real-time EKAM estimation method is expected to help patients with knee OA better control frontal plane knee loading and reduce knee OA development and progression.

Changes in the Preferred Transition Speed With Added Mass to the Foot

This study was conducted to investigate whether adding mass to subjects’ feet affects the preferred transition speed (PTS), and to ascertain whether selected swing phase variables (maximum ankle dorsiflexion angular velocity, angular acceleration, joint moment, and joint power) are determinants of the PTS, based upon four previously established criteria. After the PTS of 24 healthy active male subjects was found, using an incremental protocol in loaded (2 kg mass added to each shoe) and unloaded (shoes only) conditions, subjects walked at three speeds (60%, 80%, and 100% of PTS) and ran at one speed (100% of PTS) on a motor-driven treadmill while relevant data were collected. The PTS of the unloaded condition (2.03 ± 0.12 m/s) was significantly greater (P< .05) than the PTS of the loaded condition (1.94 ± 0.13 m/s). Within both load conditions, all dependent variables increased significantly with walking speed, decreased significantly when gait changed to a run, and were assumed to provide the necessary input to signal a gait transition, fulfilling the requirements of the first three criteria, but only ankle angular velocity reached a critical level before the transition, satisfying all four criteria to be considered a determinant of the PTS.

Development of an elliptical trainer with real-time knee adduction moment feedback

The external knee adduction moment (EKAM) is associated with knee osteoarthritis (OA) in many aspects including its presence, progression, and severity. Despite of its importance, there is a lack of EKAM estimation methods that can provide patients with knee OA a real-time EKAM biofeedback during training and be used for routine clinical evaluations outside motion analysis laboratories. Thus, a practical real-time EKAM estimation method, which utilizes kinematic variables from a simple 6-DOF goniometer, was developed to provide patients with knee OA a real-time feedback of their EKAM during stepping on elliptical trainers (ETs) to reduce the damaging EKAM. Feasibility of the proposed method was verified on seven healthy subjects. Combined with advantages of ETs (e.g., functional weight-bearing stepping, mitigation of delivery of impulsive forces), the real-time EKAM estimation method is expected to benefit patients with knee OA.