bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Organizing Role of Nonmuscular Forces During Performance of a Giant Circle in Gymnastics
Authors: Sevrez Violaine , Rao Guillaume , Berton Eric , Bootsma Reinoud J.
Published: August 2016

Five elite gymnasts performed giant circles on the high bar under different conditions of loading (without and with 6-kg loads attached to the shoulders, waist or ankles). Comparing the gymnasts’ kinematic pattern of movement with that of a triple-pendulum moving under the sole influence of nonmuscular forces revealed qualitative similarities, including the adoption of an arched position during the downswing and a piked position during the upswing. The structuring role of nonmuscular forces in the organization of movement was further reinforced by the results of an inverse dynamics analysis, assessing the contributions of gravitational, inertial and muscular components to the net joint torques. Adding loads at the level of the shoulders, waist or ankles systematically influenced movement kinematics and net joint torques. However, with the loads attached at the level of the shoulders or waist, the load-induced changes in gravitational and inertial torques provided the required increase in net joint torque, thereby allowing the muscular torques to remain unchanged. With the loads attached at the level of the ankles, this was no longer the case and the gymnasts increased the muscular torques at the shoulder and hip joints. Together, these results demonstrate that expert gymnasts skillfully exploit the operative nonmuscular forces, employing muscle force only in the capacity of complementary forces needed to perform the task.
Trunk Acceleration for Neuroprosthetic Control of Standing: A Pilot Study
Authors: Nataraj Raviraj , Audu Musa L. , Kirsch Robert F. , Triolo Ronald J.
Published: August 2016

This pilot study investigated the potential of using trunk acceleration feedback control of center of pressure (COP) against postural disturbances with a standing neuroprosthesis following paralysis. Artificial neural networks (ANNs) were trained to use three-dimensional trunk acceleration as input to predict changes in COP for able-bodied subjects undergoing perturbations during bipedal stance. Correlation coefficients between ANN predictions and actual COP ranged from 0.67 to 0.77. An ANN trained across all subject-normalized data was used to drive feedback control of ankle muscle excitation levels for a computer model representing a standing neuroprosthesis user. Feedback control reduced average upper-body loading during perturbation onset and recovery by 42% and peak loading fby 29% compared with optimal, constant excitation.
Limited Forearm Motion Compensated by Thoracohumeral Kinematics When Performing Tasks Requiring Pronation and Supination
Authors: Pereira Barry P. , Thambyah Ashvin , Lee Taeyong
Published: August 2016

This study investigates the altered thoracohumeral kinematics when forearm rotation is restricted while performing five activities requiring pronation and supination. Two splints simulated both a fixed-supinated or fixed-neutral forearm in six healthy subjects; the three-dimensional coupled relationship among motion about the forearm, elbow, and shoulder were analyzed. In using a screwdriver, the normal range of forearm rotation of 77.6° (SD = 30.8°) was reduced in the fixed-supinated to 11.3° (SD = 2.9°) and fixed-neutral to 18.2° (SD = 6.2°). This restriction from the fixed-supinated and fixed-neutral forearms was compensated at the shoulder by a significant increase in the total range of (1) ad/abduction by 57.3° and 62.8° respectively (p < .001), (2) forward-reverse flexion (24.3° and 18.2° respectively; p < .05) and (3) internal-external rotation (37.1° and 44.2° respectively; p < .001). A similar result was demonstrated for the doorknob activity. The elbow did not significantly contribute to forearm rotation (p = .14), and is believed to be due to the elbow axis being orthogonal and oblique to the forearm axis. For open kinetic-chain activities, with a fixed-supinated forearm performing there was a significant coupled increase in ad/abduction (p < .05) and int/external rotation (p < .05) for the phone and feeding tasks, with the phone task also having a significantly increased forward shoulder flexion (p < .05). For the fixed-neutral forearm, significant compensatory movement was only seen in the feeding task with increased ad/abduction and internal-external shoulder rotation (p < .05) and the card inserting task with increased ad/abduction and forward-reverse shoulder flexion. Limited forearm function requires compensatory motion from adjacent joints to perform activities that require pronation and supination. This study quantifies the compensatory mechanism about the shoulder in a forearm limited in prosupination.
Knee Kinematic Coupling in Males and Females: Open and Closed-Chain Tasks
Authors: Zifchock Rebecca Avrin , Pratt Kristamarie , Brown Allison , Hillstrom Howard
Published: August 2016

The purpose of this study was to compare the magnitude of knee kinematic coupling between genders and among open- and closed-chain tasks. A secondary purpose was to compare the consistency of knee kinematic coupling between genders and among open- and closed-chain tasks. Vector-coding methods were used to quantify coupling in the sagittal and transverse planes of the knee between full extension and 20 degrees of flexion as 10 males and 10 females walked, ascended and descended stairs, and performed a passive pendulum leg drop. An ANOVA showed no main effect of gender. There was a main effect of task, where coupling during the stance phase of walking was significantly greater than each of the other tasks. Intraclass correlation values suggested that males were slightly more consistent than females. A general lack of divergence between genders may be related to the tasks analyzed in this study. It is possible that more strenuous tasks may elicit larger differences.
A Single Video Camera Postural Assessment System to Measure Rotation of the Shoulder During Computer Use
Authors: Bruno Jennifer L. , Li Zhizhong , Trudeau Matthieu , Raina Sachin M. , Dennerlein Jack T.
Published: August 2016

The goal of this study was to evaluate the performance of a single video camera system for measuring shoulder rotation during computer work, and to quantify the work and postural space within which the system performs optimally. Shoulder rotation angles calculated using the video system were compared with angles calculated using an active infrared LED three-dimensional motion analysis system while 10 adult volunteers simulated postures for two different trials: typical of normal computer work (freestyle) and with forced shoulder abduction (constrained). Average and absolute errors were calculated to determine the accuracy and precision of the system, respectively, for each trial, for each position, and for both the right and left hands. For the right hand, mean values for the average and absolute errors were –1 and 0 degrees, respectively. Only the absolute error increased significantly to 12 degrees for the constrained posture compared with freestyle. During normal computer work, the video system provided shoulder rotation angle values similar to those of a three-dimensional system, thus making it a viable and simple instrument to use in field studies.
The Effects of Railroad Ballast Surface and Slope on Rearfoot Motion in Walking
Authors: Kwon Young-Hoo , Hutcheson Lonn , Casebolt Jeffrey B. , Ryu Joong-Hyun , Singhal Kunal
Published: August 2016

The purpose of this study was to investigate the effects of transversely sloped ballasted walking surface on gait and rearfoot motion (RFM) parameters. Motion analysis was performed with 20 healthy participants (15 male and 5 female) walking in six surface-slope conditions: two surfaces (solid and ballasted) by three slopes (0, 5, and 10 degrees). The gait parameters (walking velocity, step length, step rate, step width, stance time, and toe-out angle) showed significant surface effect (p= .004) and surface-slope interaction (p= .017). The RFM motion parameters (peak everted/inverted position, eversion/inversion velocity, and acceleration) revealed significant surface (p= .004) and slope (p= .024) effects. The ballasted conditions showed more cautious gait patterns with lower walk velocity, step length, and step rate and longer stance time. In the RFM parameters, the slope effect was more notable in the solid conditions due to the gait adaptations in the ballasted conditions. Ballast conditions showed reduced inversion and increased eversion and RFM range. The RFM data were comparable to other typical walking conditions but smaller than those from running.
Are Joint Torque Models Limited by an Assumption of Monoarticularity?
Authors: Lewis Martin G.C. , King Mark A. , Yeadon Maurice R. , Conceição Filipe
Published: August 2016

This study determines whether maximal voluntary ankle plantar flexor torque could be more accurately represented using a torque generator that is a function of both knee and ankle kinematics. Isovelocity and isometric ankle plantar flexor torques were measured on a single participant for knee joint angles of 111° to 169° (approximately full extension) using a Contrex MJ dynamometer. Maximal voluntary torque was represented by a 19-parameter two-joint function of ankle and knee joint angles and angular velocities with the parameters determined by minimizing a weighted root mean square difference between measured torques and the two-joint function. The weighted root mean square difference between the two-joint function and the measured torques was 10 N-m or 3% of maximum torque. The two-joint function was a more accurate representation of maximal voluntary ankle plantar flexor torques than an existing single-joint function where differences of 19% of maximum torque were found. It is concluded that when the knee is flexed by more than 40°, a two-joint representation is necessary.
Evaluation of Two Methods of the Jump Float Serve in Volleyball
Authors: MacKenzie Sasho , Kortegaard Kyle , LeVangie Marc , Barro Brett
Published: August 2016

A novel jump-focused (JF) technique of the jump float serve was compared with the conventionally used contact-focused (CF) method. Seven elite male (height: 195 ± 6 cm) and two elite female (height: 181 and 182 cm) volleyball players were videoed at 60 Hz performing both techniques. Horizontal and vertical ball contact coordinates, pre- and postcontact ball velocities, and initial projection angles were determined. The JF technique resulted in a significantly higher mean contact height, t(8) = 4.12, p = .006, d = 0.72, initial serve speed, t(8) = 4.71, p = .006, d = 2.03, and significantly flatter initial projection angle, t(8) = 2.53, p = .036, d = 0.63, relative to the CF technique. The precontact vertical ball velocity was also significantly higher, t(8) = 8.04, p = .004, d = 2.86. The higher precontact vertical ball velocity suggests it is more difficult to make accurate contact with the ball during the JF technique. However, this method promotes a more favorable ball trajectory and a greater initial serve speed. When combining the random lateral movement patterns inherent in any float serve, with the reduced flight time associated with the JF technique, a more challenging passing scenario can be presented to the defensive team in comparison with the current CF technique.
The Effects of Postseason Break on Knee Biomechanics and Lower Extremity EMG in a Stop-Jump Task: Implications for ACL Injury
Authors: Dai Boyi , Sorensen Christopher J. , Derrick Timothy R. , Gillette Jason C.
Published: August 2016

The effects of training on biomechanical risk factors for anterior cruciate ligament (ACL) injuries have been investigated, but the effects of detraining have received little attention. The purpose of this study was to evaluate the effects of a one-month postseason break on knee biomechanics and lower extremity electromyography (EMG) during a stop-jump task. A postseason break is the phase between two seasons when no regular training routines are performed. Twelve NCAA female volleyball players participated in two stop-jump tests before and after the postseason break. Knee kinematics, kinetics, quadriceps EMG, and hamstring EMG were assessed. After one month of postseason break, the players demonstrated significantly decreased jump height, decreased initial knee flexion angle, decreased knee flexion angle at peak anterior tibial resultant force, decreased prelanding vastus lateralis EMG, and decreased prelanding biceps femoris EMG as compared with prebreak. No significant differences were observed for frontal plane biomechanics and quadriceps and hamstring landing EMG between prebreak and postbreak. Although it is still unknown whether internal ACL loading changes after a postseason break, the more extended knee movement pattern may present an increased risk factor for ACL injuries.
Comparative Analysis of Active Drag Using the MAD System and an Assisted Towing Method in Front Crawl Swimming
Authors: Formosa Danielle P. , Toussaint Huub M. , Mason Bruce R. , Burkett Brendan
Published: August 2016

The measurement of active drag in swimming is a biomechanical challenge. This research compared two systems: (i) measuring active drag (MAD) and (ii) assisted towing method (ATM). Nine intermediate-level swimmers (19.7 ± 4.4 years) completed front crawl trials with both systems during one session. The mean (95% confidence interval) active drag for the two systems, at the same maximum speed of 1.68 m/s (1.40–1.87 m/s), was significantly different (p = .002) with a 55% variation in magnitude. The mean active drag was 82.3 N (74.0–90.6 N) for the MAD system and 148.3 N (127.5–169.1 N) for the ATM system. These differences were attributed to variations in swimming style within each measurement system. The inability to measure the early catch phase and kick, along with the fixed length and depth hand place requirement within the MAD system generated a different swimming technique, when compared with the more natural free swimming ATM protocol. A benefit of the MAD system was the measurement of active drag at various speeds. Conversely, the fixed towing speed of the ATM system allowed a natural self-selected arm stroke (plus kick) and the generation of an instantaneous force-time profile.
Joint Torques and Joint Reaction Forces During Squatting With a Forward or Backward Inclined Smith Machine
Authors: Biscarini Andrea , Botti Fabio M. , Pettorossi Vito E.
Published: August 2016

We developed a biomechanical model to determine the joint torques and loadings during squatting with a backward/forward-inclined Smith machine. The Smith squat allows a large variety of body positioning (trunk tilt, foot placement, combinations of joint angles) and easy control of weight distribution between forefoot and heel. These distinctive aspects of the exercise can be managed concurrently with the equipment inclination selected to unload specific joint structures while activating specific muscle groups. A backward (forward) equipment inclination decreases (increases) knee torque, and compressive tibiofemoral and patellofemoral forces, while enhances (depresses) hip and lumbosacral torques. For small knee flexion angles, the strain-force on the posterior cruciate ligament increases (decreases) with a backward (forward) equipment inclination, whereas for large knee flexion angles, this behavior is reversed. In the 0 to 60 degree range of knee flexion angles, loads on both cruciate ligaments may be simultaneously suppressed by a 30 degree backward equipment inclination and selecting, for each value of the knee angle, specific pairs of ankle and hip angles. The anterior cruciate ligament is safely maintained unloaded by squatting with backward equipment inclination and uniform/forward foot weight distribution. The conditions for the development of anterior cruciate ligament strain forces are clearly explained.
A Functional PCA Model for the Study of Time Series of Pressure Maps
Authors: Chicote Juan C. , Durá Juan V. , Belda Juan M. , Poveda Rakel
Published: August 2016

Principal component analysis and functional regression are combined in a model to analyze a time series of pressure maps. The model is tested measuring the pressures over a chair seat while a subject performs a combination of simple movements. A sampling rate of 3 Hz is adequate for applying the model in sitting postures. The model is able to detect patterns of movement over time, although more variables are necessary if the movements produce similar pressure distributions.
Lumbar Muscle Activity During Common Lifts: A Preliminary Study Using Magnetic Resonance Imaging
Authors: Mayer John M. , Graves James E. , Manini Todd M. , Nuzzo James L. , Ploutz-Snyder Lori L.
Published: August 2016

The purpose of this preliminary study was to assess lumbar multifidus, erector spinae, and quadratus lum-borum muscle activity during lifts as measured by changes in transverse relaxation time (T2) from magnetic resonance imaging (MRI). Thirteen healthy adults performed dynamic squat, stoop, and asymmetric stoop lifts at a standard load, with each lift followed by MRI. Increase in T2 for the multifidus and erector spinae was greater for the stoop than squat. No difference in T2 increase was noted between the multifidus and erector spinae for the squat or stoop. Increase in T2 for the contralateral multifidus was less for the asymmetric stoop than stoop. Future research using MRI and other biomechanical techniques is needed to fully characterize lumbar muscle activity during lifts for various populations, settings, postures, and loads.
Three-Dimensional Knee Kinematics by Conventional Gait Analysis for Eleven Motor Tasks of Daily Living: Typical Patterns and Repeatability
Authors: Scheys Lennart , Leardini Alberto , Wong Pius D. , Van Camp Laurent , Callewaert Barbara , Bellemans Johan , Desloovere Kaat
Published: August 2016

The availability of detailed knee kinematic data during various activities can facilitate clinical studies of this joint. To describe in detail normal knee joint rotations in all three anatomical planes, 25 healthy subjects (aged 22–49 years) performed eleven motor tasks, including walking, step ascent and descent, each with and without sidestep or crossover turns, chair rise, mild and deep squats, and forward lunge. Kinematic data were obtained with a conventional lower-body gait analysis protocol over three trials per task. To assess the repeatability with standard indices, a representative subset of 10 subjects underwent three repetitions of the entire motion capture session. Extracted parameters with good repeatability included maximum and minimum axial rotation during turning, local extremes of the flexion curves during gait tasks, and stride times. These specific repeatable parameters can be used for task selection or power analysis when planning future clinical studies.
Quantification of Tibiofemoral Shear and Compressive Loads Using an MRI-Based EMG-Driven Knee Model
Authors: Tsai Liang-Ching , Scher Irving S. , Powers Christopher M.
Published: August 2016

The purpose of this study is to describe an MRI-based EMG-driven knee model to quantify tibiofemoral compressive and shear forces. Twelve healthy females participated. Subjects underwent 2 phases of data collection: (1) MRI assessment of the lower extremity to quantify muscle volumes and patella tendon orientation and (2) biomechanical evaluation of a drop-jump task. A subject-specific EMG-driven knee model that incorporated lower extremity kinematics, EMG, and muscle volumes and patella tendon orientation estimated from MRI was developed to quantify tibiofemoral shear and compressive forces. A resultant anterior tibial shear force generated from the ground reaction force (GRF) and muscle forces was observed during the first 30% of the stance phase of the drop-jump task. All of the muscle forces and GRF resulted in tibiofemoral compression, with the quadriceps force being the primary contributor. Acquiring subject-specific muscle volumes and patella tendon orientation for use in an EMG-driven knee model may be useful to quantify tibiofemoral forces in persons with altered patella position or muscle atrophy following knee injury or pathology.
Effects of Prosthetic Mass Distribution on Metabolic Costs and Walking Symmetry
Authors: Smith Jeremy D. , Martin Philip E.
Published: August 2016

Unilateral, transtibial amputees exhibit walking asymmetries and higher metabolic costs of walking than nonamputees walking at similar speeds. Using lightweight prostheses has previously been suggested as a contributing factor to walking asymmetries. The purpose was to investigate the effects of prosthesis mass and mass distribution on metabolic costs and walking asymmetries among six unilateral, transtibial amputees. Kinematic and temporal symmetry did not improve when mass was added at different locations on the limb. Stance and swing time asymmetries increased by 3.4% and 7.2%, respectively, with loads positioned distally on the limb. Maximum knee angular velocity asymmetries increased by 6% with mass added to the thigh, whereas maximum thigh angular velocity asymmetries increased by approximately 10% with mass positioned near the prosthetic ankle. Adding 100% of the estimated mass difference between intact and prosthetic legs to the ankle of the prosthesis increased energy costs of walking by 12%; adding the same mass to the prosthesis center of mass or thigh center of mass increased metabolic cost by approximately 7% and 5%, respectively. Unless other benefits are gained by increasing prosthesis mass, this should not be considered as a possible alternative to current lightweight prosthesis designs currently being prescribed to unilateral amputees.
Comparison of Interfinger Connection Matrix Computation Techniques
Authors: Martin Joel R. , Terekhov Alexander V. , Latash Mark L. , Zatsiorsky Vladimir M.
Published: August 2016

A hypothesis was proposed that the central nervous system controls force production by the fingers through hypothetical neural commands. The neural commands are scaled between values of 0 to 1, indicating no intentional force production or maximal voluntary contraction (MVC) force production, respectively. A matrix of interfinger connections transforms neural commands into finger forces. Two methods have been proposed to compute the interfinger connection matrix. The first method uses only single finger MVC trials and multiplies the interfinger connection matrix by a gain factor. The second method uses a neural network model based on experimental data. The performance of the two methods was compared on the MVC data and on a data set of submaximal forces, collected over a range of total forces and moments of force. The methods were compared in terms of (1) ability to predict finger forces, (2) accuracy of neural command reconstruction, and (3) preserved planarity of force data for submaximal force production task. Both methods did a reasonable job of predicting the total force in multifinger MVC trials; however, the neural network model performed better in regards to all other criteria. Overall, the results indicate that for modeling multifinger interaction the neural network method is preferable.
Reliability of a Measure of Total Lumbar Spine Range of Motion in Individuals with Low Back Pain
Authors: Al Zoubi Fadi M. , Preuss Richard A.
Published: August 2016

Measuring lumbar spine range of motion (ROM) using multiple movements is impractical for clinical research, because finding statistically significant effects requires a large proportion of subjects to present with the same impairment. The purpose of this study was to develop a single measure representing the total available lumbar ROM. Twenty participants with low back pain performed three series of eight lumbar spine movements, in each of two sessions. For each series, an ellipse and a cubic spline were fit to the end-range positions, measured based on the position of the twelfth thoracic vertebra in the transverse plane of the sacrum. The area of each shape provides a measure of the total available ROM, whereas their center reflects the movements’ symmetry. Using generalizability theory, the index of dependability for the area and anterior-posterior center position was found to be 0.90, but was slightly lower for the mediolateral center position. Slightly better values were achieved using the spline-fitting approach. Further analysis also indicated that excellent reliability, and acceptable minimal detectable change values, would be achieved with a single testing session. These data indicate that the proposed measure provides a reliable and easily interpretable measure of total lumbar spine ROM.
The Influence of Body Mass Index and Gender on the Impact Attenuation Properties of Flooring Systems
Authors: Bhan Shivam , Levine Iris , Laing Andrew C.
Published: August 2016

The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.
Abstracts from StairMaster Conference on Aging and Physical Activity
Authors: Rikli Roberta
Published: August 2016

The following are abstracts of poster presentations accepted for the StairMaster Conference on Aging and Physical Activity, October 21–23, 1993, in Virginia Beach, Virginia. In planning the conference, the goal for both the invited presentations and poster sessions was to include a balance of scientific research, professional application, and program development information. The abstracts are organized alphabetically according to the last name of the first author. A special thank you goes to the Journal of Aging and Physical Activity reviewers who participated in the review process. Articles based on the invited conference presentations will appear in future issues of the Journal.
Age as a Poor Predictor of Blood-Lactate and Heart-Rate Responses during Club-Level Orienteering
Authors: Bird Steve R. , George Meirion , Theakston Simon , Smith Mark , Burrows Melonie , Balmer James , Davison R.C. Richard
Published: August 2016

This study investigated heart-rate (HR) and lactate responses of 31 club-level orienteers (age 23-68 years) during competitions in technically easy (TE) and technically difficult (TD) terrain. HR was monitored throughout the events, and capillary-blood samples for lactate analysis were taken at a midpoint and at the finish. HR and lactate responses were relatively consistent within and between events. Orienteering speed and mean lactate levels were lower in the more complex terrain (TE 5.6 vs. TD 4.1 mmol/L). Age was not a predictor of lactate values. The peak HR for both events was 175 ± 10 beats/min and decreased with age by 2–5 beats · min · decade−1. Mean HR was TE, 162 ± 11, and TD, 156 ± 14 beats/min, and did not decline with age. Participants older than 45 years frequently displayed peak and mean HR responses exceeding those predicted from commonly applied age-related algorithms.
Differences in Physical-Fitness Test Scores between Actively and Passively Recruited Older Adults: Consequences for Norm-Based Classification
Authors: van Heuvelen Marieke J.G. , Stevens Martin , Kempen Gertrudis I.J.M.
Published: August 2016

This study investigated differences in physical-fitness test scores between actively and passively recruited older adults and the consequences thereof for norm-based classification of individuals. Walking endurance, grip strength, hip flexibility, balance, manual dexterity, and reaction time were measured in participants age 57 years or older: 1 sample recruited through media announcements (passively recruited) and 1 sample recruited through personal contact (actively recruited). Classifications on a 5-point scale based on norms were cross-tabulated. Compared with the actively recruited sample, performance of the passively recruited sample was significantly better on all tests except, for women, hip flexibility and manual dexterity. Cross-tabulation of the 2 classifications showed that percentages of agreement varied from 27.4% to 87.4%. Cohen's Kappa varied from .11 to .84. Caution should be used when giving feedback on test performance and subsequently making physical activity recommendations if norms are based on the performance of passively recruited older adults.
Promoting Functional Independence among “At Risk” and Physically Frail Older Adults through Community-Based Fall-Risk-Reduction Programs
Authors: Rose Debra J.
Published: August 2016

In recent years, a number of research investigations have been conducted in an effort to determine whether declining balance and mobility among older adults can be reversed or at least slowed. Unfortunately, the results of a number of these studies have not yielded positive outcomes. Three reasons are forwarded to account for these unsuccessful outcomes: the lack of a contemporary theory-based approach to the problem, the failure to use multiple and diverse measures of balance and mobility, and the failure to design multidimensional interventions that target the actual source(s) of the balance or mobility-related impairments. A model fall-risk-reduction program designed to address each of the shortcomings associated with previous research findings is presented. The program is group based and suitable for implementation in community-based and residential care facilities.
Dissemination and Implementation of “Aging Well and Healthily”: A Health-Education and Exercise Program for Older Adults
Authors: Westhoff Marja H. , Hopman-Rock Marijke
Published: August 2016

The article describes the dissemination and implementation of the Aging Well and Healthily (AWH) program in the Netherlands. In the period 1997–1999 this process was monitored by means of telephone interviews with 263 participants, 28 peer educators, and 13 organizers. The program participants were mainly physically active and relatively healthy people in their mid 70s. The peer educators were in their late 50s. The overall satisfaction with the content and delivery of the AWH program was good; 13% of the participants enrolled in related local sports activities. In total, the AWH program was run 57 times, which did not meet the target of 50 times a year. Different factors could have negatively influenced dissemination. In the first place, the organization of the program was perceived to be complex and not compatible with the values of the organizations that were to implement the program. Also, 3 national implementation partners had organizational problems of their own. The results were used to design a new social marketing strategy, which appears to be successful.
Influence of Age on Immune Changes in Runners after a Marathon
Authors: Pistilli Edward E. , Nieman David C. , Henson Dru A. , Kaminsky David E. , Utter Alan C. , Vinci Debra M. , Davis J. Mark , Fagoaga Omar R. , Nehlsen-Cannarella Sandra L.
Published: August 2016

Immune changes in 75 younger (age 37.4 ± 0.9 years) and 23 older (57.0 ± 1.4 years) runners were compared after a competitive marathon, with blood samples collected pre- and immediately and 1.5 hr postrace. Race times were slower for the older group (4.7 ± 0.2 vs. 4.3 ± 0.1 hr, p = .015), but both groups performed at similar intensity (83.4 ± 0.9 vs. 82.9 ± 0.5% HRmax). The pattern of change in plasma cortisol, epinephrine, growth hormone, and blood leukocyte subsets did not differ significantly between the groups postrace. Blood lymphocyte counts were 20–24% lower in the older runners at each time point because of reduced T-cell counts. Postrace, plasma levels of IL-1ra, -10, -6, and -8 rose strongly in all runners, and salivary IgA secretion rate decreased, but no group differences in the pattern of change were noted. In conclusion, younger and older runners experienced similar hormonal and immune changes after running a marathon.
Measuring Lower Extremity Strength in Older Adults: The Stability of Isokinetic versus 1RM Measures
Authors: Salem George J. , Wang Man-Ying , Sigward Susan
Published: August 2016

In order to obtain joint-specific baseline strength characteristics in older adults, clinicians and researchers must have knowledge regarding the relative stability of the various strength tests (the strength difference between repeated measures) and the number of prebaseline practice sessions required to obtain consistent data. To address these needs, the relative multiple-test stability and reliability associated with lower extremity isokinetic and 1-repetition-maximum (1RM) strength measures were assessed in a sample of older adults (N= 30, 65.2 ± 6.3 years), over 4 weeks (T1-T4). Isokinetic ankle plantar-flexion (30°/s) strength and 1RM ankle plantar-flexion, leg-press, and knee-flexion strength exhibited poor stability between Weeks T1 and T2 but stabilized between Weeks T2 and T3 and Weeks T3 and T4. The measures exhibited low incidence of injury and induced low levels of residual muscle soreness. Findings suggest that the 1RM measures require at least 1 prebaseline training session in order to establish consistent baseline performance and are more reliable than isokinetic ankle plantar-flexion tests.
Balance Self-Efficacy Predicts Risk Factors for Side Falls and Frequent Falls in Community-Dwelling Elderly
Authors: Gunter Katherine B. , De Costa Jennifer , White Karen N. , Hooker Karen , Hayes Wilson C. , Snow Christine M.
Published: August 2016

This study assessed changes in balance self-efficacy (BSE) over 1 year in community-dwelling elderly, compared changes in BSE between fallers and nonfallers, and assessed the relationship between specific balance and mobility risk factors for side falls and BSE scores. Elderly fallers (n = 67; 80.2 ± 5.9 years) and nonfallers (n = 75; 79.4 ± 4.9), categorized based on self-reported falls over 1 year, were tested at baseline on postural sway, hip-abduction strength, lateral-stepping velocity, tandem walk, and get-up-and-go and given a BSE questionnaire. Fallers had lower BSE scores than nonfallers did (141.6 ± 33.5 and 154.9 ± 25.4; p = .008). BSE did not change over 1 year. In stepwise regression, BSE scores were predictive of time on the get-up-and-go, mediolateral sway, and tandem walk independent of age, height, and strength (p < .001). The BSE scale might be useful for screening individuals at risk for injurious falls because it is inexpensive and noninvasive.
A Study of Perceived Constraints on a Community-Based Physical Activity Program for the Elderly in Greece
Authors: Alexandris Konstantinos , Barkoukis Vasilis , Tsorbatzoudis Haralambos , Grouios George
Published: August 2016

The purpose of the study was to examine whether older adults (>60 years old) who participated in physical activity programs provided by a senior center in Greece perceived certain constraints as limiting reasons for their participation and whether perceived constraints could predict individuals’ intentions to continue participation. The sample of the study consisted of 125 adults age 60 and older. The principal-component analysis of the leisure-constraint scale revealed 4 constraint dimensions: facilities/services, individual/psychological, lack of partners, and accessibility/financial. The results revealed significant differences in the perception of constraints between frequent and infrequent participants in the individual/psychological and accessibility/financial constraints. The constraint dimensions were also shown to predict a significant and fairly high (40%) proportion of the variance in older adults’ intention to continue participation. The individual/psychological and accessibility/financial constraint dimensions were shown to be the major predictors. The implications of these results for promoting physical activity programs among older adults are discussed.
Characteristics Associated with 10-km Running Performance among a Group of Highly Trained Male Endurance Runners Age 21–63 Years
Authors: Bird Stephen R. , Theakston Simon C. , Owen Andrew , Nevill Alan M.
Published: August 2016

This study assessed physiological and cardiac factors associated with 10-km running performance in a group of highly trained endurance runners age 21–63 years. Participants (N = 37) underwent a resting echocardiograph and incremental treadmill running test. They also provided information on their recent 10-km races. Data were analyzed using “best subsets” multiple regression. Declines with age were found for 10-km running speed (0.26 m · s−1 · decade−1), maximum heart rate (4 beats/decade), VO2peak (6 ml · kg−1 · min−1 · decade−1), velocity at lactate threshold (1 m · s−1 · decade−1), and VO2 at lactate threshold (4 ml · kg−1 · min−1 · decade−1). The percentage of VO2peak at which lactate threshold occurred increased with age by 1.5% per decade. The rate of change of displacement of the atrioventricular plane at the left free wall and septum both declined by 1 cm · s−1 · decade−1. The best single predictor of 10-km running speed was velocity at lactate threshold.
From Supervised to Unsupervised Exercise: Factors Associated with Exercise Adherence
Authors: Morey Miriam C. , Dubbert Patricia M. , Doyle Martha E. , MacAller Helga , Crowley Gail M. , Kuchibhatla Maggie , Schenkman Margaret , Horner Ronnie D.
Published: August 2016

Getting older adults to initiate and maintain long-term exercise is an important public health mandate. This study is an analysis of a clinical trial of 112 sedentary adults, age 65–90 years, randomly assigned to 1 of 2 exercise interventions. We examined predictors and patterns of adherence of the 6-month home-based component of the trial. Telephone follow-up and diaries were used to assess adherence. Adherence to weekend exercise during the supervised phase of the program was the strongest predictor of subsequent home-based adherence. Adherence appeared stable throughout the intervention, indicating that adherence or nonadherence was established from the outset. The authors conclude that nonadherence can be identified early in the behavioral-change process. Future studies should focus on developing strategies for adults with chronic illnesses, depressive symptoms, and functional limitations who are nonadherent early on as they initiate and attempt to maintain exercise.
Aging, Physical Activity, and Hormones in Women—A Review
Authors: Copeland Jennifer L. , Chu Samuel Y. , Tremblay Mark S.
Published: August 2016

Women experience significant changes in endocrine function during aging. Decreasing levels of anabolic hormones may be associated with musculoskeletal atrophy and decrease in function that is observed in older women and, as a result, there has been an increase in the use of pharmacological hormone therapies. It is difficult to distinguish, however, between physiological changes that are truly age related and those that are associated with lifestyle factors such as physical activity participation. Some research has shown that circulating levels of anabolic hormones such as DHEA(S) and IGF-I in older women are related to physical activity, muscle function, and aerobic power. Exercise-intervention studies have generally shown that increasing age blunts the acute hormonal response to exercise, although this might be explained by a lower exercise intensity in older women. There have been relatively few studies that examine hormonal adaptations to exercise training. Physical activity might have an effect on hormone action as a result of changes in protein carriers and receptors, and future research needs to clarify the effect of age and exercise on these other components of the endocrine system. The value and safety of hormone supplements must be examined, especially when used in combination with an exercise program.
Bicycle Ergometry in Subacute-Stroke Survivors: Feasibility, Safety, and Exercise Performance
Authors: Yates Joni S. , Studenski Stephanie , Gollub Steven , Whitman Robert , Perera Subashan , Lai Sue Min , Duncan Pamela W.
Published: August 2016

This study evaluated the feasibility, safety, and findings from a protocol for exercise-bicycle ergometry in subacute-stroke survivors. Of 117 eligible candidates, 14 could not perform the test and 3 discontinued because of cardiac safety criteria. In the 100 completed tests, peak heart rate was 116 ± 19.1 beats/min; peak VO2was 11.4 ± 3.7 ml · kg · min−1, peak METs were 3.3 ± 0.91, exercise duration was 5.1 ± 2.84 min., and Borg score was 14 ± 2.6. Among 71 tests, anaerobic threshold was achieved in 3.0 ± 1.7 min with a VO2of 8.6 ± 1.7 ml · kg · min−1. After screening, this protocol is feasible and safe in subacute-stroke survivors with mild to moderate deficits. These stroke survivors have severely limited functional exercise capacity. Research and clinical practice in stroke rehabilitation should incorporate more comprehensive evaluation and treatment of endurance limitations.
Artificial Neural Networks and Center-of-Pressure Modeling: A Practical Method for Sensorimotor-Degradation Assessment
Authors: Shan Gongbing , Daniels Dayna , Gu Rongri
Published: August 2016

Numerous methods for studying the prevention of falls and age-related sensorimotor degradation have been proposed and tested. Some approaches are too impractical to use with seniors or too expensive for practitioners. Practitioners desire a simple, reliable technique. The goals of this research were to develop such an approach and to apply it in exploring the effect of Tai Chi on age-related sensorimotor degradation. The method employed artificial-neural-network (ANN) models trained by using individuals’ center-of-pressure (COP) measurements and age. Ninety-six White and Chinese adults without Tai Chi training were tested. In contrast, a third group, Chinese seniors with Tai Chi training, was tested to ascertain any influence from Tai Chi on sensorimotor aging. This study supported ANN technology with COP data as a feasible tool in the exploration of sensorimotor degradation and demonstrated that Tai Chi slowed down the effects of sensorimotor aging.
Relationship between Balance and Gait Stability in Healthy Older Adults
Authors: Cromwell Ronita L. , Newton Roberta A.
Published: August 2016

Age-related adaptations during walking create a more stable walking pattern, which is less effective for forward progression and might be related to balance deficiencies. This study determined the relationship between walking stability and measures of balance in older adults. Seventeen older and 20 young adults performed the Berg Balance Test (BBT) and walked 10 m. Walking velocity (WV) and cadence were measured, and a gait-stability ratio (GSR) was calculated. Higher GSR indicated that a greater portion of the gait cycle was spent in double-limb support. Age-group comparisons established declines in BBT scores and WV and increases in GSR with age. Significant relationships were identified for BBT Item 12 (alternate stepping on a stool) with WV (r = .58, r 2 = .34) and GSR (r = −.74, r2 = .54). The correlation of BBT Item 12 with GSR was stronger than with WV (p < .05). Results indicated a strong relationship between increased gait stability and decreased balance for a dynamic weight-shifting task. Therefore, GSR is a better indicator of balance deficits during walking than is WV alone.
Comparison of Heart-Rate and Blood-Pressure Increases during Isokinetic Eccentric versus Isometric Exercise in Older Adults
Authors: Huggett Deanna L. , Elliott Ian D. , Overend Tom J. , Vandervoort. Anthony A.
Published: August 2016

The authors compared heart-rate and blood-pressure responses to typical isometric (ISO) and isokinetic (90°/s) eccentric (ECC) resistance-training protocols in older adults. Twenty healthy older adults (74 ± 5 years old) performed randomly ordered ISO and isokinetic ECC exercise (3 sets of 10 repetitions) at a target intensity of 100% of their peak ISO torque value. Heart rate and systolic (SBP) and diastolic (DBP) blood pressures were recorded continuously, and mean arterial pressure (MAP) and rate-pressure product (RPP) were calculated. ECC peak torque (139 ± 33 N · m) was significantly greater than ISO peak torque (115 ± 26 N · m; p < .001). All variables increased significantly (p < .001) during both ISO and ECC exercise. Changes in SBP, DBP, MAP, and RPP were significantly greater during ISO exercise than during ECC exercise (p < .001). Clinically, an isokinetic ECC exercise program enables older adults to work at the same torque output with less cardiovascular stress than ISO exercise.
Physical-Performance Tests to Evaluate Mobility Disability in Community-Dwelling Elders
Authors: Wang Ching-Yi , Olson Sharon L. , Protas Elizabeth J.
Published: August 2016

The purposes of this study were to evaluate community-dwelling elderly adults with different levels of perceived mobility with 5 physical-performance tests, determine the cutoff values of the 5 tests, and identify the best tests for classifying mobility status. The community-mobility statuses of 203 community-dwelling elders were classified as able, decreased, or disabled based on their self-reported ability to walk several blocks and climb stairs. They also performed the functional reach, timed 50-ft walk, timed 5-step, timed floor transfer, and 5-min-walk endurance tests. We found in all tests that the “able” outperformed the “decreased” and that the “decreased” outperformed the “disabled,” except on the floor-transfer task. The optimum cutoff values of the 5 performance tests were also reported. The 5-min walk and timed 5-step test could best separate the “able” from the “decreased,” whereas the 50-ft-walk-test could best differentiate the “decreased” from the “disabled.” The results suggest that community-mobility function of older adults can be captured by performance tests and that the cutoff values of the 5-min-walk, 5-step, and 50-ft-walk tests can be used in guiding intervention or prevention programs.
The Association between Mood States and Physical Activity in Postmenopausal, Obese, Sedentary Women
Authors: Carels Robert A. , Berger Bonnie , Darby Lynn
Published: August 2016

Mood states influence evaluative judgments that can affect the decision to exercise or to continue to exercise. This study examined how mood associated with graded exercise testing (GXT) in sedentary, obese, postmenopausal women (N = 25) was associated with physical activity and predicted VO2max during and after a behavioral weight-loss program (BWLP). Measures of physical activity included planned exercise, calories from physical activity, leisure-time physical activity, and predicted VO2max. Mood before and after pre-BWLP GXT was assessed using the Profile of Mood States. Mood before and after the GXT was more strongly associated with planned exercise than other forms of physical activity, and this effect became stronger over time. Mood enhancement in response to exercise was not related to physical activity. Mood before and after exercise might yield important clinical information that can be used to promote physical activity in sedentary adults.