Comparative analysis of speed's impact on muscle demands during partial body weight support motor-assisted elliptical training

Energy expenditure, oxygen consumption, and heart rate while exercising on seven different indoor cardio machines at maximum and self-selected submaximal intensity

Objective

One of the main objectives of practicing indoor cardiovascular exercise is to maximize caloric expenditure. This study aimed to compare energy expenditure (EE), oxygen consumption (VO2), and heart rate (HR) recorded in middle-aged adults while exercising on seven different indoor cardiovascular machines at self-selected maximal and submaximal intensity.

Method

Thirty recreational-active adult males (Age: 41.69 ± 4.64) performed 12-min bouts at RPE (Rate of perceived exertion) 17 and maximum intensity (MAX INT) on the following indoor cardio machines: Recumbent bike (r_BIKE), upright bike (u-BIKE), spin bike (s-BIKE), rowing machine (ROW), elliptical trainer (ELLIP), stair climber (STAIR), and treadmill (TMILL). Heart rate (HR) and oxygen consumption (VO2) were measured during exercise, whereas EE (energy expenditure) was calculated indirectly.

Results

Overall, TMILL induced the highest levels of EE, VO2, and HR, followed by STAIR, ELLIP, s_BIKE, u_BIKE, ROW, and r_BIKE. RPE was reliable across exercise modalities (r_BIKE, u-BIKE, s-BIKE, ROW, ELLIP, STAIR, and TMILL) and intensities (RPE 17 and MAX INT) for EE, HR, and VO2 measurements.

Conclusion

To maximize EE while performing indoor cardiovascular exercise for recreational active middle-aged male participants, the TMILL is the best option, followed by the STAIR and the ELLIP. The least recommended options are, respectively, s_BIKE, u_BIKE, ROW, and r_BIKE. Beyond caloric expenditure considerations, promoting exercises that participants genuinely enjoy can enhance adherence, fostering sustained health benefits. Furthermore, RPE is a reliable tool for assessing EE, VO2, and HR across different exercise modalities and intensities.

Effect of gap-filling technique and gap location on linear and nonlinear calculations of motion during locomotor activities

BACKGROUND

Marker occlusion during camera-based movement analysis is common. Different interpolation techniques are available for estimating location of missing marker trajectories.

RESEARCH QUESTION

What is the effect of gap location and interpolation technique on linear and nonlinear measures for a given kinematic time series?

METHODS

Kinematic data were recorded during motor-assisted elliptical training and treadmill walking. Gap-filling techniques (i.e., Cubic, Makima, Autoregressive, Nearest Neighbor, and No Interpolation) and gap locations experimentally applied to each cycle across initially complete time series (Gap 1: local minimum and maximum peaks; Gap 2: maximum peaks; Gap 3: maximum peaks at negative slope; Gap 4: random locations) were examined during linear (Maxima and Minima joint angles) and nonlinear [maximum Lyapunov exponent (LyE)] measures.

RESULTS

Gap-filling technique and gap location influenced values calculated for linear and nonlinear measures of joint motions. When referenced to the gold standard (original data series without gaps), across all joints studied the average % error of Maxima and Minima joint angles and LyE % error were lower when applying Cubic, Makima, Autoregressive, and Nearest Neighbor techniques compared to No Interpolation (p < 0.0001). The % error of Maxima joint angles was lower for Gaps 1, 3, and 4 compared to Gap 2 (p = 0.0003), while % error of Minima joint angles was lower for Gaps 2 and 3, compared to Gaps 1 and 4 (p < 0.0001). An interaction between gap-filling technique and gap location was identified for LyE % error, in which Gap 4 % error was significantly greater during No Interpolation compared to other gap-filling techniques (p < 0.0001).

SIGNIFICANCE

Findings can guide selection of appropriate techniques to manage missing kinematic data points in camera-based motion analysis time series. Gap-filling techniques significantly reduced error in calculating select linear and nonlinear measures of variability, with Cubic most consistently resulting in the greatest reduction in error.

Feasibility of motor-assisted elliptical to improve walking, fitness and balance following pediatric acquired brain injury: A case series

PURPOSE

Walking, fitness, and balance deficits are common following acquired brain injury (ABI). This study assessed feasibility, acceptability, and usefulness of a modified motor-assisted elliptical (ICARE) in addressing walking, fitness, and balance deficits in children with chronic ABIs.

METHODS

Three children (> 5 years post-ABI) completed 24 ICARE exercise sessions (exercise time, speed, and time overriding motor-assistance gradually increased) to promote mass repetition of gait-like movements and challenge cardiorespiratory fitness. Parents' and children's perceptions of ICARE's safety, comfort, workout, and usability were assessed. Cardiovascular response, gait and balance outcomes were assessed.

RESULTS

No adverse events occurred. Parent's Visual Analogue Scale (VAS) scores of perceived device safety (range 80-99), workout (range 99-100), and usability (range 75-100) were high, while comfort were 76-80 given commercial harness fit and arm support. Children's VAS scores all exceeded 89. Comfortable walking velocity, 2-Minute Walk Test, fitness, and Pediatric Balance Scale scores improved post-training, with many outcomes surpassing established minimal clinically important differences.

CONCLUSION

Following engagement in moderate- to vigorous-intensity exercise promoting repetitive step-like movements on a specially adapted motor-assisted elliptical, three children with chronic ABI demonstrated improvements in walking, fitness and balance. Future research in community-based environments with a larger cohort of children with ABI is needed.

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.

Effect of motor-assisted elliptical training speed and body weight support on center of pressure movement variability

BACKGROUND

A motor-assisted elliptical trainer is being used clinically to help individuals with physical disabilities regain and/or retain walking ability and cardiorespiratory fitness. Unknown is how the device's training parameters can be used to optimize movement variability and regularity. This study examined the effect of motor-assisted elliptical training speed as well as body weight support (BWS) on center of pressure (CoP) movement variability and regularity during training.

METHODS

CoP was recorded using in-shoe pressure insoles as participants motor-assisted elliptical trained at three speeds (20, 40 and 60 cycles per minute) each performed at four BWS levels (0 %, 20 %, 40 %, and 60 %). Separate two-way repeated measures ANOVAs (3 × 4) evaluated impact of training speed and BWS on linear variability (standard deviation) and non-linear regularity (sample entropy) of CoP excursion (anterior-posterior, medial-lateral) for 10 dominant limb strides.

FINDINGS

Training speed and BWS did not significantly affect the linear variability of CoP in the anterior-posterior or medial-lateral directions. However, sample entropy in both directions revealed the main effect of training speed (p < 0.0001), and a main effect of BWS was observed in the medial-lateral direction (p = 0.004). Faster training speeds and greater levels of BWS resulted in more irregular CoP patterns.

INTERPRETATION

The finding that speed and BWS can be used to manipulate CoP movement variability when using a motor-assisted elliptical has significant clinical implications for promoting/restoring walking capacity. Further research is required to determine the impact of motor-assisted elliptical speed and BWS manipulations on functional recovery of walking in individuals who have experienced a neurologic injury or illness.

Comparison of knee biomechanical characteristics during exercise between pinnacle and step trainers

BACKGROUND

A novel stair-climber called a pinnacle trainer (PT) provides both sagittal and frontal plane exercise, making it different from a step trainer (ST), which provides only sagittal plane exercise. Exercise with different trajectories may produce different biomechanical responses. There are currently no guidelines for choosing between a PT and a ST for different training or rehabilitation purposes.

RESEARCH QUESTIONS

Are there differences in the electromyographic patterns of lower extremity musculature and biomechanical responses of the knee joint during exercise between using a PT and a ST?

METHODS

This study utilizes a prospective observational study design. Eighteen healthy males participated in the study. A six-axis force and torque transducer embedded in the machine pedal synchronized with a three-dimensional motion capture system were utilized to measure kinematic and kinetic data of the right knee during the stepping movement. The activities of six lower extremity muscles of the same limb were captured with surface electromyography during exercise on the two trainer types.

RESULTS

The co-activation index of the vastus lateralis (VL) and the biceps femoris (BF) recorded during ST exercise was significantly greater than that for the PT exercise. Moreover, exercise using the ST produced a significantly greater knee downward force compared to that for the PT. Exercise with the PT produced a significantly greater internal knee varus moment compared to that for the ST.

SIGNIFICANCE

The ST provided greater co-activation of the BF and VL and a greater knee joint downward force, which may decrease the antero-posterior displacement of the tibia relative to the femur. Exercise with the PT produced a significant internal knee varus moment and a more balanced muscular activation on the vastus medialis and VL compared to that for the ST, which may decrease the maltracking of the patella.

Effects of body weight support and pedal stance width on joint loading during pinnacle trainer exercise

BACKGROUND

A pinnacle trainer is a stair climber that has a biplane exercise trajectory and an adjustable pedal stance width (PSW). A pinnacle trainer integrated with a body weight support (BWS) system can help overweight individuals or individuals with poor balance exercise safely by reducing excessive or improper joint loads, preventing training-related injuries. However, few studies have investigated the biomechanical features of the lower extremities during pinnacle trainer exercise with and without partial BWS for various PSWs.

RESEARCH QUESTION

We aimed to investigate the effects of partial BWS and PSW on the joint loading of the lower extremities during stepping on a pinnacle trainer.

METHODS

Seventeen healthy adults exercised on the pinnacle trainer with or without BWS using various PSWs. The joint resultant forces and joint moments of the lower extremities were calculated according to the kinematic and kinetic data measured via a motion capture system and force transducers on the pedals, respectively.

RESULTS

The joint resultant forces and joint moments of the lower extremities significantly decreased with increasing percentage of BWS. The internal knee adduction moment and internal hip abduction moment significantly increased with increasing PSW. For every kilogram of BWS, the joint loading of the lower extremities decreased by approximately 1% of the joint resultant forces of body weight during exercise with the pinnacle trainer.

SIGNIFICANCE

Exercise on the pinnacle trainer with partial BWS significantly reduced joint loading. Exercise with a wider pedal stance may be helpful for knee osteoarthritis rehabilitation as it produces greater internal hip abduction and internal knee adduction moments.

Adapted Motor-Assisted Elliptical for Rehabilitation of Children With Physical Disabilities

Many children with physical disabilities experience difficulty using traditional exercise equipment for gait rehabilitation and fitness training, and the clinician resources required to deliver intensive overground or treadmill-based therapies are infrequently available in most clinics, hospitals, and school settings. This work describes design and testing of a comprehensive set of modifications that enabled children to use a commercially available robotic exercise device (i.e., Intelligently Controlled Assistive Rehabilitation Elliptical (ICARE)) initially developed to address walking and fitness goals of adults with physical disabilities and chronic conditions. Fifteen children (3–11 years old) concurrently enrolled in physical therapy due to varied neurologic conditions were recruited with their parent(s) to evaluate the safety, comfort, and usability of the adult ICARE and pediatric-modified ICARE. After children tried each device, feedback was recorded. To assess feasibility, each child then participated in up to ten sessions (two to five sessions per week; average session length: 38 min, range 21–66 min) using the pediatric-modified ICARE. Parents, on average, perceived that the pediatric-modified ICARE was significantly safer, more comfortable and usable than the adult ICARE. Children's perceptions of the pediatric-modified ICARE were similar, although not statistically significant. Children used the prototype device during 133 sessions for over 3800 min and more than 162,000 cycles. In conclusion, this study demonstrated the feasibility of using the pediatric-modified ICARE with children as young as 3 years old as an adjunct to ongoing therapy.

Walking and Fitness Improvements in a Child With Diplegic Cerebral Palsy Following Motor-Assisted Elliptical Intervention

PURPOSE

To quantify effects of motor-assisted elliptical (Intelligently Controlled Assistive Rehabilitation Elliptical [ICARE]) training on walking and fitness of a child with cerebral palsy (CP).

KEY POINTS

A 12-year-old boy with walking limitations due to spastic diplegic CP (Gross Motor Function Classification System II) participated in 24 sessions of primarily moderate- to vigorous-intensity ICARE exercise. Fitness improvements were evidenced clinically across sessions by the child's capacity to train for longer periods, at faster speeds, and while overriding motor's assistance. Postintervention, the child walked faster with greater stability and endurance and more rapidly completed the modified Time Up and Go test.

CONCLUSION

The child's fitness and gait improved following engagement in a moderate- to vigorous-intensity gait-like exercise intervention.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Integration of moderate- to vigorous-intensity motor-assisted elliptical training can promote simultaneous gains in fitness and function for children with CP.

Treadmill training with partial body-weight support after anterior cruciate ligament reconstruction: a randomized controlled trial

[Purpose] To compare the effects of treadmill training with partial body weight support (TTPBWS) and conventional physical therapy (PT) on subjects with anterior cruciate ligament reconstructions. [Subjects and Methods] A total of 40 subjects were randomly allocated to either a treatment group or a control group. Subjects received either treadmill training with partial body weight support (treatment group) or conventional physical therapy (control group). The circumferences of the lower extremities, Holden classifications, 10-meter walking times and the International Knee Documentation Committee (IKDC) scores were compared at 12 and 24 weeks post-operation. The knee joint stability was tested at 24 weeks post-operation using a KT-1000. [Results] Significant differences were found between the two groups at the 12 weeks post-operation. For most of the measures, there was no significant difference between the groups at 24 weeks post-operation. Interestingly, for most of the measures, there was no significant difference between their values in the treatment group at 12 weeks and their values in the control group at 24 weeks post-operation. [Conclusion] The function of a subject’s lower extremities can be improved and the improvement was clearly accelerated by the intervention of treadmill training with partial body weight support, without compromising the stability of the knee joints in a given follow-up period.

Kinematic and muscle demand similarities between motor-assisted elliptical training and walking: Implications for pediatric gait rehabilitation

Many children with physical disabilities and special health care needs experience barriers to accessing effective therapeutic technologies to improve walking and fitness in healthcare and community environments. The expense of many robotic and exoskeleton technologies hinders widespread use in most clinics, school settings, and fitness facilities. A motor-assisted elliptical trainer that is being used to address walking and fitness deficits in adults was modified to enable children as young as three years of age to access the technology (Pedi-ICARE). We compared children's kinematic and muscle activation patterns during walking and training on the Pedi-ICARE. Eighteen children walked (self-selected comfortable speed), Pedi-ICARE trained with motor-assistance at self-selected comfortable speed (AAC), and trained while over-riding motor-assistance (AAC+). Coefficient of multiple correlations (CMCs) compared lower extremity kinematic profiles during AAC and AAC+ to gait. Repeated measures ANOVAs identified muscle demand differences across conditions. CMCs revealed strong similarities at the hip and knee between each motor-assisted elliptical condition and gait. Ankle CMCs were only moderate. Muscle demands were generally lowest during AAC. Over-riding the motor increased hip and knee muscle demands. The similarity of motion patterns between Pedi-ICARE conditions and walking suggest the device could be used to promote task-specific training to improve walking. The capacity to manipulate muscle demands using different motor-assistance conditions highlights Pedi-ICARE's versatility in addressing a wide range of children's abilities.

Biomechanical effects of body weight support with a novel robotic walker for over-ground gait rehabilitation

Body weight support (BWS) promotes better functional outcomes for neurologically challenged patients. Despite the established effectiveness of BWS in gait rehabilitation, the findings on biomechanical effects of BWS training still remain contradictory. Therefore, the aim of this study is to comprehensively investigate the effects of BWS. Using a newly developed robotic walker which can facilitate pelvic motions with an active BWS unit, we compared gait parameters of ten healthy subjects during a 10-m walk with incremental levels of body weight unloading, ranging from 0 to 40 % at 10 % intervals. Significant changes in joint angles and gait temporospatial parameters were observed. In addition, the results of an EMG signal study showed that the intensity of muscle activation was significantly reduced with increasing BWS levels. The reduction was found at the ankle, knee, and hip joints in the sagittal plane as well as at the hip joint in the frontal plane. The results of this study provide an important indication of increased lateral body balance and greater stabilization in sagittal and frontal plane during gait. Our findings provide a better understanding of the biomechanical effects of BWS during gait, which will help guide the gait rehabilitation strategies.

Modification of the ICARE System for Pediatric Therapy

Effective gait therapy is critical to children who have difficulty walking due to developmental, neurologic, or orthopedic conditions. Current gait training technologies can be cost prohibitive and often do not address the needs of children of varying sizes. In addition, clinicians often need to provide significant physical assistance to children with profound weakness. Based on the success of an elliptical-based adult-sized intelligently controlled assistive rehabilitation elliptical (ICARE) system for gait training, a modified technology was proposed to address the needs of younger/smaller children. The new design relied on a screw-and-slider joint to adjust the effective length of the crank link in the elliptical mechanism, reducing the step length and stride height simultaneously. The new trajectories of the foot pedal were normalized against stride length and showed nearly identical trajectories between pediatric strides and adult strides. Simulation results and human usability studies verified that the design was feasible.