Exercise Difficulty Research Articles

Ability to Predict Impending Volitional Exhaustion Based on Aerobic Capacity

Maximal relative oxygen consumption (VO2max), assessed via a treadmill test to volitional exhaustion, is the foremost measure of aerobic capacity in healthy, recreationally active young adults. Habitual exercise may improve the ability to perceive exercise difficulty and predict impending exhaustion. PURPOSE: The primary aim of this investigation was to determine if a correlation existed between VO2max and time to test termination after participants indicated they were 30 s from volitional exhaustion. A secondary aim was to ascertain if participants more accurately predicted impending exhaustion during a repeated trial. METHODS: Participants completed a familiarization trial to minimize learning effects and determine treadmill speed for maximal testing. During the familiarization trial, participants self-selected a zero-grade jogging speed associated with a value of 12-13 on Borg’s 6-20 RPE scale when steady-stated. This speed was used during two maximal tests separated by 36-72 h. During maximal testing, grade was increased 2% every two minutes until volitional exhaustion. VO2max was measured as a 15-breath moving average via a metabolic cart. Participants were instructed before and during testing to tap on the treadmill when they perceived themselves to be 30 s from volitional exhaustion. RESULTS: Thirteen (Females: 8, Males: 5) recreationally active individuals (20.7 ± 1.4 yrs., 72.4 ± 12.3 kg) completed the protocol. Mean VO2max during session 1 (10.00 ± 2.46 min) was 47.0 ± 7.4 ml⋅kg-1⋅min-1, and time to test termination after the tap was 36.2 ± 7.4 s. Mean VO2max during session 2 (10.08 ± 2.38 min) was 47.5 ± 7.7 ml⋅kg-1⋅min-1, and time to test termination after the tap was 40.0 ± 18.5 s. No significant correlation was detected between VO2max and time to test termination after the tap in session 1 (r = -.032, p = .917) or session 2 (r = .315, p = .295). A dependent t-test (t(12) = -.800, p = .439) did not reveal significant differences in time to test termination after the tap between session 1 and session 2. CONCLUSIONS: Aerobic capacity did not affect the ability of healthy, recreationally active young adults to predict impending volitional exhaustion during maximal treadmill running. Time to test termination after the tap did not significantly change during a repeated trial.

Exploring dynamic difficulty adjustment mechanism for rehabilitation tasks using physiological measures and subjective ratings

Task engagement is a key factor in sustaining patients’ participation in rehabilitation. Adaptive task difficulty level adjustment techniques are designed to determine the appropriate exercise difficulty level in where subjects are appropriately challenged and engaged without causing any distress. Such adaptive difficulty adjustment within rehabilitation tasks has the potential to individualise training. In this study, the authors have compared two dynamic difficulty level adjustment algorithms, partially ordered set master (POSM) and increment/decrement one level (IDOL), those change the difficulty levels for each individual adaptively based on his/her performance. These two algorithms are integrated into the robot-assisted rehabilitation system, RehabRoby, and their functionality is explored via a small user study with 20 healthy subjects. The subjects were asked to perform a computer-based fruit picker game using RehabRoby under these two algorithms. The impacts of the adaptation algorithms are evaluated in terms of engagement of the subjects by looking at their physiological signals, performance (score), and survey results. Experiments show that although POSM on the average suggests easier difficulty levels to the subjects than IDOL, the subjects experience a wider range of difficulty levels in POSM that may help them to become more engaged in the game, which can also be observed by lower skin temperatures of the subjects.

Can mat Pilates intervention increase lower limb rate of force development in overweight physically active older women?

This study investigated the effect of 12 weeks of mat Pilates intervention (60 min sessions, three times per week) on lower limb rate of force development (RFD) parameters (absolute and relative values and contractile impulse) in physically active and overweight elderly women. Fourteen elderly women (age 62 ± 3 years) participated in this study. Workouts were performed in three sets; repetitions increased every 4 weeks, and exercise difficulty increased from beginner to intermediate and advanced levels. Knee extensor and hip extensor–flexor RTD parameters were measured at different time intervals (0–30, 0–50, 0–100, 0–150, 0–200, and 0–250 ms) before (weeks − 4 and 0, control period) and after 6 and 12 weeks of mat Pilates intervention. No statistical difference (p > 0.05) was observed between weeks − 4 and 0 (control period). However, significant increments were observed after week 12 for most time intervals for absolute and relative knee extensor and hip extensor–flexor RFD, as well as for contractile impulse for the same muscle groups. We conclude that the mat Pilates causes significant increments in knee extensor and hip extensor–flexor RFD and contractile impulse using an incremental structure of training in physically active elderly women.

INDIVIDUAL APPARATUS RESULTS OF FEMALE ALL AROUND OLYMPIC CHAMPIONS

The changes of Code of Points stimulate the rise in exercise difficulty and a drive towards increased specialization of gymnasts. We inspected the performance of all-around medalists at individual apparatus finals to analyze the trends in their efficiency to reach the podium. Data from Olympic games 1952-2016 was included in this retrospective study. In the period form 1952-1984 there were 5 occasions when all-round winners reached 75 to 100% efficiency in reaching the podium at all individual apparatus finals. However overall, there is a clear trend of diminished efficiency of all-around winners to reach the podium at individual finals in the observed period (1952-2016) from the average of 7.7 medals in the first three observed events to 4.3 medals at the last three observed events. Olympic all-around champion efficiency was calculated from sum of all medals won by all-around champions on apparatuses divided by 4. This efficiency has decreased from 91.7% in the first three events to 41.7% in the last three events. In recent events all-around champions still managed to win at least one medal on single apparatuses as there was only one exception to this rule at 2012. It is very much probable that in the future all-around champions will excel further at single apparatus finals; however a huge predominance of all-around champions at apparatus finals cannot be expected any more.

Design and research potential of interactive textbooks: the case of fractions

The transition from classical to electronic textbooks seems to be a logical step in the digitization advancing worldwide. However, developing an e-book ought to be more than digitizing text: key features of computer-based learning environments such as interactive exercises, adaptive demands, or automatic feedback should be integrated to take advantage of the digitization. The “ALICE:fractions” project aims at designing and evaluating an interactive mathematics textbook for introducing fractions in the classroom. It is based on research in mathematics education and includes the elements just mentioned. This paper describes the electronic textbook’s implementation and its theoretical background. Moreover, it introduces aspects that allow further information on learning processes to be gleaned. As an example, time on task is regarded in a study with 6th graders who used the electronic textbook in the classroom. Linear mixed models revealed a negative effect of time on task on task success. The effect was moderated by exercise difficulty and slightly by student competence: the effect was less pronounced in difficult exercises and for low-achieving students, whereas for high-achieving students or in easier exercises, the effect intensified.

Feasibility and Acceptability of Qigong Exercise in Community-Dwelling Older Adults in the United States.

Qigong exercise has been shown to improve physical and psychological well-being in adults with chronic conditions, but little is known about the feasibility and acceptability of engaging in a qigong exercise program in community-dwelling older adults in the United States. The purpose of this study was to explore the feasibility, acceptance, and adherence to an 8-week qigong exercise intervention in community-dwelling American older adults. An exploratory study design. Two senior centers in southern Connecticut. Forty-five community-dwelling older adults aged 65 to 85 years enrolled. A supervised 1-h health qigong exercise session twice weekly for 8 weeks. An investigator-designed questionnaire with seven items that were rated on a 1 to 6 scale, with higher scores indicating better results, and nine open-ended questions were used to obtain data on feasibility and acceptability. Adherence was calculated as the proportion of the 16 planned sessions attended. Of the 45 older adults enrolled, 6 never started and 6 withdrew, with 33 evaluable at the end of the intervention. The mean age of the sample was 74.8 years; the majority were female (84.4%) and white (91.1%). Mean scores on aspects of difficulty, acceptability, suitability, or effectiveness of qigong exercise were all ≥5. Participants identified benefits of qigong exercise, such as calming and relaxing feelings, inner peace, better balance, and flexibility. Attendance rate was 78.8%, with 94% performing qigong exercise at least once weekly outside the class. All participants indicated that they would recommend qigong exercise to others. No adverse events occurred. An 8-week qigong exercise program was feasible, acceptable, and safe for American older adults. Future robust randomized controlled trials are needed to confirm these findings.

Watching easy sports makes me eat more

Does simply watching sports influence food consumption? Findings on the influence of exercise cues on food consumption are mixed: while some research suggests exposure to exercise cues increases food consumption, other suggests the opposite. We add to this literature by investigating the effect of advertisements portraying various levels of exercise difficulty on subsequent food consumption, providing an explanation for contradictions in prior work. Through two experiments we show that the effect of exercise cues on snack consumption varies according to perceived exercise difficulty. We demonstrate that viewing an advertisement portraying easy to perform, compared to harder to perform, sports leads to increased chocolate consumption for females. While it may seem intuitive to promote physical activity and healthy eating simultaneously, we show that the ease of the exercise portrayed may increase food consumption — ultimately backfiring efforts set in place to combat obesity.

Associations between walking parameters and subsequent sleep difficulty in older adults: A 2-year follow-up study

PurposeThis 2-year follow-up study aimed to examine the associations between total volume, frequency, duration, and speed of walking with subsequent sleep difficulty in older adults. MethodsA total of 800 older adults aged 65 years and over participated in the first survey in 2012 and 511 of them were followed 2 years later. The 5-item Athens Insomnia Scale (AIS-5) was used to measure sleep difficulty. Frequency, duration, and speed of outdoor walking were self-reported. Walking speed was assigned a metabolic equivalent value (MET) from 2.5 to 4.5. Total walking volume in MET-h/week was calculated as frequency × duration × speed. Negative binomial regressions were performed to examine the associations between volume and components of walking with subsequent sleep difficulty with covariates of age, sex, education, marital status, living arrangement, smoking, alcohol consumption, mental health, Charlson Index, exercise (excluding walking), and sleep difficulty at baseline. ResultsParticipants with low walking volume had a higher level of sleep difficulty 2 years later compared with those with high walking volume (incident rate ratios = 1.61, p = 0.004). When speed, frequency, and duration of walking were simultaneously entered into 1 model, only walking speed was significantly associated with subsequent sleep difficulty (after the model was adjusted for covariates and baseline sleep difficulty). Sensitivity analyses showed that walking duration emerged as a significant predictor among 3 walking parameters, with 2-year changes of sleep scores as dependent variable. ConclusionTotal amount of walking (especially faster walking and lasting for more than 20 min) is associated with less subsequent sleep difficulty after 2 years among older adults.

Automatic estimation of exercises' difficulty levels in a tutoring system for teaching the conversion of natural language into first‐order logic

AbstractThe estimation of the difficulty level of exercises is a fundamental aspect of intelligent tutoring systems, and it is necessary in order to achieve better adaptation to the students' needs and maximize learning efficiency. In this article, we present an approach to automatically estimates the difficulty level of exercises in natural language (NL) to first‐order of logic (FOL). The estimation of an exercise's difficulty level is based on the complexity of the corresponding answer, that is the FOL formula, as well as the structure and the semantics of the exercise, that is a natural language sentence and it is carried out in two main steps. Initially, a preliminary estimation is performed based on the complexity of the FOL formula. The system takes as input parameters the number, the type and the order of quantifiers, the number of implications, and the number of different connectives. Afterwards, the final estimation is made based on both semantic aspects of the NL sentence and the structure of the FOL formula. An evaluation study was conducted to assess the system's performance, and the results are very encouraging.

Individual Differences in Post-exercise Ad Libitum Energy Intake in Children

Previous studies have shown individual differences in the energy intake (EI) response to exercise, but homeostatic or cognitive mechanisms underlying these differences are unclear, particularly in youth. Fat-free mass is a known predictor of daily EI in adolescents and adults, predominantly through its effects on resting metabolic rate and total energy expenditure. In addition, studies in adults have shown that increased perceived difficulty of exercise is associated with caloric over-compensation through greater EI. However, the influence of these biological and psychological factors in children is unknown. PURPOSE: To examine the predictors of post-exercise EI in children. METHODS: Healthy-weight children ages 9–12 years (n = 18) reported to the laboratory for 1 baseline and 2 experimental visits (EX = exercise, SED = sedentary) each separated by 1 week in a randomized crossover design. Percent body fat (bioelectrical impedance analysis), weight (kg), and height (m) were used to calculate fat-mass index (FMI) and fat-free mass index (FFMI; kg/m2). On the EX day, children exercised at 70% estimated VO2peak for 30 minutes on a cycle ergometer and gave ratings of perceived exertion (RPE). Objective EI (kcal) was measured at identical meals on the EX and SED days: standard breakfast and ad libitum lunch, snack, and dinner. Paired t-tests, Pearson’s correlations, and multiple linear regressions were performed using SPSS. RESULTS: Total EI was not statistically different between the EX and SED days (t = 0.47, p = 0.64). However, FFMI was positively associated with EI on the EX day (r = 0.50, p < 0.05), but not the SED day (p = 0.25). RPE was also positively associated with EI on the EX day (r = 0.78, p < 0.01). Together, FFMI and RPE explained 71% of the variability in EI on the EX day (F(2,15) = 17.14, p < 0.01). CONCLUSIONS: Fat-free mass was associated with EI on the EX day but not the SED day, suggesting better homeostatic regulation of EI with imposed exercise. Despite experiencing the same 70% relative exercise intensity, children varied in their perceived difficulty of the exercise. Increased perceived difficulty predicted greater EI on the EX day. These findings demonstrate a role for both homeostatic and cognitive factors in post-exercise EI regulation in children. Supported by USDA/NIFA Grant #2011-67001-30117 Program A2121.

Novel Use of a Smartphone to Measure Standing Balance.

BackgroundBalance assessment and training is utilized by clinicians and their patients to measure and improve balance. There is, however, little consistency in terms of how clinicians, researchers, and patients measure standing balance. Utilizing the inherent sensors in every smartphone, a mobile application was developed to provide a method of objectively measuring standing balance.ObjectiveWe aimed to determine if a mobile phone application, which utilizes the phone’s accelerometer, can quantify standing balance.MethodsThree smartphones were positioned simultaneously above the participants’ malleolus and patella and at the level of the umbilicus. Once secured, the myAnkle application was initiated to measure acceleration. Forty-eight participants completed 8 different balance exercises separately for the right and left legs. Accelerometer readings were obtained from each mobile phone and mean acceleration was calculated for each exercise at each ankle and knee and the torso.ResultsMean acceleration vector magnitude was reciprocally transformed to address skewness in the data distribution. Repeated measures ANOVAs were completed using the transformed data. A significant 2-way interaction was revealed between exercise condition and the body position of the phone (P<.001). Post-hoc tests indicated higher acceleration vector magnitude for exercises of greater difficulty. ANOVAs at each body position were conducted to examine the effect of exercise. The results revealed the knee as the location most sensitive for the detection of differences in acceleration between exercises. The accelerometer ranking of exercise difficulty showed high agreement with expert clinical rater rankings (kappa statistic>0.9).ConclusionsThe myAnkle application revealed significantly greater acceleration magnitude for exercises of greater difficulty. Positioning of the mobile phone at the knee proved to be the most sensitive to changes in accelerometer values due to exercise difficulty. Application validity was shown through comparison with clinical raters. As such, the myAnkle app has utility as a measurement tool for standing balance.

Deep abdominal muscle thickness measured under sitting conditions during different stability tasks.

[Purpose] This study was conducted to investigate ultrasonically determined changes in the thickness of the transversus abdominis and internal oblique muscles during different sitting conditions. [Subjects and Methods] Twenty healthy men volunteered to participate in this study. Four different sitting conditions including (A) sitting, (B) sitting with left hip flexion, (C) sitting with an abdominal hollowing maneuver (AHM), and (D) sitting with an AHM and left hip flexion, were used. Subjective exercise difficulty was evaluated. [Results] Transversus abdominis and internal oblique muscle thicknesses significantly differed between conditions, with significantly greater thickness between positions from (A) to (D). Stability of the surface when sitting had no effect on the muscle thickness of the transversus abdominis. By contrast, sitting on an unstable surface caused an increase in muscle thickness of the internal oblique in each condition. The subjects reported progressively increasing difficulty in performing each exercise in a stable position from (A) to (D), while the difficulty in an unstable position was significantly different between (A) and (B), and between (C) and (D). [Conclusion] Our findings suggest that task (B) on a stable surface should be chosen for maximal activation of transversus abdominis without inducing overactivation of the internal oblique muscle.

Treinamento neuromotor no padrão de marcha e na mobilidade de tornozelos em idosos

Objective: To analyze the effect of neuromotor training on gait pattern and mobility of ankles in older people. Methods: A cross-sectional non-randomized controlled study conducted in Rio Negrinho, Santa Catarina, from May to September 2015 with a sample of 26 older women divided into control group (CG=15) and neuromotor training group (NETG=11). The gait pattern was assessed through the Cerny Protocol and the mobility of ankles through goniometry. The CG performed regular physical activity including warm-up, stretching and strengthening of major muscle groups and cool-down. The NETG performed a neuromotor training as a 10-station circuit including warm-up, neuromotor training, cool-down and repetition of the circuit three times, remaining one minute at each station and keeping a 30-second interval between the stations. The exercise difficulty level increased after the sixth week. Both groups performed the activity for 12 weeks (twice a week for 45 minutes). The analysis was performed using the t-test with a significance level of p<0.05. Results: A significant improvement was observed in dorsiflexion of both ankles (right ankle p=0.00 and left ankle=0.02) and in both groups; however, the gait pattern did not present a significant improvement after the neuromotor exercise training (speed p=0.55; time to ambulation p=0.6). Conclusion: The neuromotor training maintained the gait pattern (speed and time to ambulation) and the mobility of ankles of the older women assessed.

Cognitive remediation for older community-dwelling individuals with schizophrenia: a pilot and feasibility study.

Cognitive deficits are among the strongest predictors of function in individuals with schizophrenia. This relationship continues to be strong as these individuals grow older into their eight decade. Cognitive remediation (CR) improves cognition in individuals with schizophrenia. This study aims at assessing the feasibility and potential effect of CR in patients with schizophrenia 60 years of age or older. We adapted a CR protocol involving restorative and strategy-based methods over four cohorts of older outpatients with schizophrenia to target cognitive deficits associated with aging and schizophrenia. CR was provided in eight, 2-h weekly didactic sessions and online at-home exercises. Computerized drill and practice exercises were used with bridging to activities of daily life. Computer exercise selection and difficulty level parameters optimized adherence. Progression individually determined difficulty levels. We modified computer laboratory ergonomics to accommodate mobility needs. Participants were assessed at baseline and end-of-study using clinical and cognitive assessments. Twenty-two participants enrolled: 18 (mean [SD] age: 69.8 [5.3]) completed CR. Mean (SD) global cognition T score from the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery was 27.7 (10) at baseline and 28.8 (9.7) at the completion of the study. These means are over 2 SD below the norms. The change in global cognition was not statistically significant (paired t(17) = -1.18, p = 0.25). Our pilot study suggests that CR is well tolerated by most older outpatients with schizophrenia. Future studies need to assess whether increasing the frequency or the number of CR sessions leads to significant improvement in cognition.

Prediction of performance reduction in self-paced exercise as modulated by the rating of perceived exertion.

Rating of perceived exertion (RPE) is a scale of exercise difficulty and has been hypothesized to be a regulator of work rate during self-pacing. The goal of this work was to develop a dynamic prediction of RPE and to characterize the control strategy employed to reduce work rate during self-paced exercise using RPE as feedback. Training and test data were acquired from the literature to develop a linear regression of RPE as a function of four physiological variables: core temperature, mean-weighted skin temperature, metabolic rate, and integral of relative oxygen consumption (R (2) = 0.85). A thermoregulatory model was used to predict core and mean-weighted skin temperature. Utilizing self-paced cycling and running data from the literature, we characterized reductions in work rate with a proportional-derivative control algorithm with RPE as feedback. Bland-Altman analysis revealed the necessity to parameterize RPE equations for untrained and endurance-trained individuals. Afterwards, dynamic predictions of RPE were accurate for a wide range of activity levels and air temperatures for walking, running, and cycling (LoA and bias of 2.3 and -0.03, respectively). For self-paced exercise, the control algorithm characterized the trend and magnitude of work rate reductions for cycling and running, and showed regulated RPE to be less conservative for shorter vs. longer duration exercise. A novel methodology to characterize self-paced work intensity, based upon dynamic physiologic response, is provided. The complete model is a useful tool that estimates performance decrements during self-paced exercise and predicts tolerance time for exhaustive fixed-rate exercise.

Exercise Limitation of Acetazolamide at Altitude (3459 m)

To assess the effect of acetazolamide (Az) on exercise performance during early acclimatization to altitude. Az (250 mg twice daily) or placebo was administered for 3 days in a double-blind, randomized manner followed by a rapid ascent to 3459 m in the Italian Alps. Twenty healthy adults (age range, 18-67 years) were tested at 60% of sea-level peak power output for 15 minutes on a bicycle ergometer after 16 to 27 hours of altitude exposure. Exercise performance was measured in relation to peripheral oxygen saturations measured from pulse oximetry (Spo2), Lake Louise acute mountain sickness (AMS) score, and perceived difficulty. At altitude, resting Spo2 was higher in the Az group compared with placebo (P < .001). The highest AMS scores were in 4 of the placebo individuals with the lowest resting Spo2 (P < .05). During the exercise test, Spo2 fell in all but 1 subject (P < .001) and was reduced more in the Az group (P < .01). Four Az and 1 placebo subject were unable to complete the exercise test; 4 of these 5 had the largest fall in Spo2. The perception of exercise difficulty was higher in the Az subjects compared with those taking the placebo (P < .01). There was an age relationship with exercise limitation; 4 of the 9 older than 50 years failed to complete the test whereas only 1 of 11 younger than 50 years failed, and there were no failures in the 6 younger than 30 years (P < .05). In this study group, and despite higher resting Spo2, Az may have compromised exercise at 3459 m altitude during early acclimatization, particularly in older subjects.

Development of a specific exercise programme for professional orchestral musicians

BackgroundMusculoskeletal problems are common in professional orchestral musicians, and little is known about effective prevention strategies. Exercise is suggested to help in reducing work-related upper limb disorders and accordingly a...

Validation of a mechanism to balance exercise difficulty in robot-assisted upper-extremity rehabilitation after stroke

BackgroundThe motivation of patients during robot-assisted rehabilitation after neurological disorders that lead to impairments of motor functions is of great importance. Due to the increasing number of patients, increasing medical costs and limited therapeutic resources, clinicians in the future may want patients to practice their movements at home or with reduced supervision during their stay in the clinic. Since people only engage in an activity and are motivated to practice if the outcome matches the effort at which they perform, an augmented feedback application for rehabilitation should take the cognitive and physical deficits of patients into account and incorporate a mechanism that is capable of balancing i.e. adjusting the difficulty of an exercise in an augmented feedback application to the patient's capabilities.MethodsWe propose a computational mechanism based on Fitts' Law that balances i.e. adjusts the difficulty of an exercise for upper-extremity rehabilitation. The proposed mechanism was implemented into an augmented feedback application consisting of three difficulty conditions (easy, balanced, hard). The task of the exercise was to reach random targets on the screen from a starting point within a specified time window. The available time was decreased with increasing condition difficulty. Ten subacute stroke patients were recruited to validate the mechanism through a study. Cognitive and motor functions of patients were assessed using the upper extremity section of the Fugl-Meyer Assessment, the modified Ashworth scale as well as the Addenbrookes cognitive examination-revised. Handedness of patients was obtained using the Edinburgh handedness inventory. Patients' performance during the execution of the exercises was measured twice, once for the paretic and once for the non-paretic arm. Results were compared using a two-way ANOVA. Post hoc analysis was performed using a Tukey HSD with a significance level of p < 0.05.ResultsResults show that the mechanism was capable of balancing the difficulty of an exercise to the capabilities of the patients. Medians for both arms show a gradual decrease and significant difference of the number of successful trials with increasing condition difficulty (F2;60 = 44.623; p < 0.01; η2 = 0.623) but no significant difference between paretic and non-paretic arm (F1;60 = 3.768; p = 0.057; η2 = 0.065). Post hoc analysis revealed that, for both arms, the hard condition significantly differed from the easy condition (p < 0.01). In the non-paretic arm there was an additional significant difference between the balanced and the hard condition (p < 0.01). Reducing the time to reach the target, i.e., increasing the difficulty level, additionally revealed significant differences between conditions for movement speeds (F2;59 = 6.013; p < 0.01; η2 = 0.185), without significant differences for hand-closing time (F2;59 = 2.620; p = 0.082; η2 = 0.09), reaction time (F2;59 = 0.978; p = 0.383; η2 = 0.036) and hand-path ratio (F2;59 = 0.054; p = 0.947; η2 = 0.002). The evaluation of a questionnaire further supported the assumption that perceived performance declined with increased effort and increased exercise difficulty leads to frustration.ConclusionsOur results support that Fitts' Law indeed constitutes a powerful mechanism for task difficulty adaptation and can be incorporated into exercises for upper-extremity rehabilitation.

Effects of Resistance Training and TaiJi Exercise on Symptoms and Physical Functions of Knee Osteoarthritis

Resistance training and TaiJi exercise have been shown to be effective in reducing symptoms of knee osteoarthritis (OA), however the actual effects are varied widely or mixed. No studies have compared the effects of resistance training and TaiJi exercise. PURPOSE: To compare the effectiveness of a 10-week Taiji intervention and a 10-week strength training intervention in senior citizens with knee OA. METHODS: Thirty one participants randomly assigned to one of the resistance training (RT, 69.5±6.7 years) and TaiJi (TJ, 68.1±5.3 years) participated in a 10-week training program along with a control group (CT, 70.5±5.0 years). OA symptoms were evaluated using the Western Ontario and MacMaster University Osteoarthritis Index (WOMAC) immediately before and after the training programs. In addition, the 6-minute walk test (6MW), the timed up-and-go test (TUG) and the timed stair climb and descent (SCD) were administered to evaluate performance of physical functions of the participants before and after the training programs. The baseline and post-training related data were compared using a 3 × 2 (group × time) mixed model ANOVA. A paired t-test was also used to detect the training effect. RESULTS: The ANOVA results showed a significant time main effect for the WOMAC total score (p = 0.018), stiffness (p = 0.012) and physical function (p = 0.038) sub-scales as well as near significant pain subscale (p = 0.052). The t-test results showed a significant improvement in the post-training score for the pain (p = 0.006, Effect Size (ES) = -0.86), stiffness (p = 0.001, ES = -1.16), physical function (p = 0.011, ES = -0.58) and total WOMAC (p = 0.004, ES = - 0.75) for the RT group. For the performance of physical functions, the ANOVA showed a significant reduction of TUG (p = 0.001) between the pre- and post-training. The t-test showed that both RT and TJ had significant improvement in this task. The time main effect for the SCD was almost significant (p = 0.072). No group differences were found. CONCLUSIONS: The results of this randomized clinical trial demonstrated that the resistance training was effective for improving mobility and improving the symptoms of knee OA. TaiJi was also effective for improving mobility, but did not improve the knee OA symptoms of the participants which may be partially due to difficulty of learning TaiJi exercise.

Perceived Barriers to Exercise in Overweight and Obese Adults on a University Campus

Obesity continues to plague our society as a health epidemic. The CDC estimates that two-third of adults are either overweight or obese. One of the contributing factors to this rise in obesity is the concurrent decrease in physical activity. PURPOSE: To define the perceived barriers to exercise in an overweight/obese adult population who are either full time students or employees. METHODS: The exercise benefits/barriers scale (EBBS) was administered using a convenient sample from our university. Subjects were identified through a campus- wide email that was sent out to all current faculty, students, and staff. Inclusion criteria for the study was BMI ≥ 25. Exclusion criteria included presence of any absolute contraindications to exercise (as defined by the ACSM) and/or advisement against exercise by a physician. One hundred subjects qualified for the study and 30 were randomly selected to participate. Subjects were asked to complete the barrier portion of the EBBS, a 14 item scale which ranks items which are barriers to exercise. The EBBS utilizes a 4 point Likert scale ranging from 1 (strongly agree) to 4 (strongly disagree). RESULTS: The ages of the participants ranged from 25- 62, and comprised of 6 males and 24 females. The BMI of the participants ranged from 26.4- 51.5 kg/m2. The items which were identified as barriers by the participants fell into 2 categories, time constraints and difficulty/discomfort associated with exercise. Specifically the participants rated the items "exercise is hard work for me" and "exercise takes too much of my time" as the 2 major barriers (rated 2.2 and 2.5 respectively). Interestingly, participants did not consider availability and cost of exercising to be barriers (rated 3.6 and 3.7 respectively). CONCLUSIONS: This is the first study to investigate perceived barriers to exercise in overweight and obese individuals who are working or are full time students. We believe we can use this data to devise strategies to increase time management skills which may improve physical activity levels. Additionally customized fitness routines which consider the subjects' baseline fitness ability and activity preferences may lessen the perception of exercise difficulty and discomfort in this demographic.