Pitching shoulder passive flexibility: torque-angle analysis for external rotation and internal rotation.

In this study, a custom device was developed to analyse the pitching shoulder's external rotation (ER) and internal rotation (IR) passive flexibility. We analysed three novel measures: the resistance onset angle (ROA = angle where the shoulder begins stretching), rotational stiffness, and torque at the end range of motion (ROM). The purpose was to conduct a bilateral analysis to determine if there are significant differences between the throwing and non-throwing shoulder. Participants were 30 upper level pitchers (13 division I, 17 minor league). During testing, pitchers laid supine on a treatment table and the arm was secured to a rotational wheel with the shoulder abducted 90° and elbow flexed 90°. Dependent t-tests revealed significant (p < 0.01) and relatively extreme bilateral differences for all three variables. The throwing shoulder had: increased ER ROA (9°), decreased IR ROA (5.3°), increased ER stiffness (17%), increased IR stiffness (34%), increased ER torque (21%), and increased IR torque (30%). Secondary correlation analysis was completed to determine if the torque-angle variables were good predictors of the end ROM. Stiffness correlations were weak for ER (r = 0.35, p = 0.048) and IR (r = 0.42, p = 0.017) but ROA correlations were strong for ER (r = 0.85, p < 0.001) and IR (r = 0.86, p < 0.001).

Carrying Asymmetric Loads While Walking on a Treadmill Interferes with Lower Limb Coordination.

The purpose of this study was to investigate the effect of different load carriage modes on coordinative patterns in the lower extremities during walking. Twenty-five university students walked on a treadmill at their preferred pace under three different load conditions: symmetric load (5% of body mass in messenger bags on each shoulder hanging vertically and against the hips), asymmetric load 1 (10% of body mass in a messenger bag on one shoulder hanging vertically against the ipsilateral hip), and asymmetric load 2 (10% of body mass in a messenger bag on one shoulder with the bag draped across the trunk to the contralateral hip). Altered thigh-shank and shank-foot couplings were found for the loaded side during the stance of gait when comparing the asymmetric 1 and 2 to the symmetric load. In addition, thigh-thigh coupling was changed during gait when comparing the asymmetric load 2 and symmetric load. However, we did not find any significant differences in intralimb and interlimb couplings between the two different asymmetric load conditions. The results suggest potential benefits when carrying symmetrical loads in order to decrease abnormal limb coordination in daily activities. Thus, it may be advisable to distribute load more symmetrically to avoid abnormal gait.

An examination of single day vs. multi-day heart rate variability and its relationship to heart rate recovery following maximal aerobic exercise in females.

The purpose of this study was to examine the relationship of a single day measure of heart rate variability (HRV), and the averaged baseline measures of HRV to heart rate recovery (HRR) following maximal exercise. Thirty females (22.9 ± 3.2 years, 64.8 ± 8.4 kg) completed four visits (V1-V4), where a 10-min HRV was recorded. Upon completing the V4 recording, a treadmill graded exercise test (GXT) was performed, followed by a 5-min active cool down. HRV was assessed through time domain measures [natural log of root mean square of successive R-R differences (lnRMSSD) and standard deviation of normal to normal intervals (lnSDNN)] and natural log frequency domain measures [low frequency (lnLF) and high frequency (lnHF)]. Variables collected over V1-V4 were measured as; day of (DO) GXT, 3 day (AV3), and 4 day average (AV4). HRR was calculated as the maximal HR achieved minus the HR at: 30-s (HRR30), 1-min (HRR1), 2-min (HRR2), 3-min (HRR3), 4-min (HRR4) or 5-min (HRR5) of recovery. Pearson's Product correlations revealed significant correlations (P = < 0.05) between all HRVDO measures to each HRR measure and are presented in ranges: lnSDNN (r = 0.442-0.522), lnRMSSD (r = 0.458-0.514), lnLF (r = 0.368-0.469), lnHF (r = 0.422-0.493). For HRVAV3, lnRMSSDAV3 and HRR1 were positively correlated (r = 0.390, P = 0.033). Last, HRVAV4 showed positive relationships (P = < 0.05) between lnRMSSDAV4 and HRR30 (r = 0.365, P = 0.048); and for HRR1 and lnSDNNAV4 (r = 0.400, P = 0.029), lnRMSSDAV4 (r = 0.442, P = 0.014), and lnHFAV4 (r = 0.368, P = 0.045); and lnRMSSDAV4 and HRR3 (r = 0.381, P = 0.038). Within the current study HRVDO displayed the strongest correlations to HRR therefore, averaged resting HRV measures do not strengthen the prediction of cardiovascular recovery following a GXT in this population.

Friberg Equation to Predict Pediatric Distal Forearm Fracture Remodeling.

BACKGROUND: This study is the first to test Friberg's equation's (Vt=V0[e]) accuracy in predicting the residual angular deformity in pediatric distal forearm fractures. METHODS: Angular deformities from distal forearm fractures in 50 children (mean age, 9 y) were retrospectively measured on follow-up radiographs once healed and compared to extrapolated angles at respective follow-up intervals from 2013 to 2015. RESULTS: The predicted and actual angulations from 120 radiographs (mean follow-up, 3mo) showed that the mean predicted angle was similar to the measured angle in the radioulnar plane and only 2 degrees greater than the measured angle in the dorsovolar plane. A strong correlation was observed between predicted and measured angles in both planes. CONCLUSIONS: Friberg's equation is a valid tool for predicting remodeling potential in pediatric distal 25% forearm fractures. LEVEL OF EVIDENCE: Prognostic Study-Level II.

Motoneuron Function Does not Change Following Whole-Body Vibration in Individuals With Chronic Ankle Instability.

CONTEXT: Following a lateral ankle sprain, ∼40% of individuals develop chronic ankle instability (CAI), characterized by recurrent injury and sensations of giving way. Deafferentation due to mechanoreceptor damage postinjury is suggested to contribute to arthrogenic muscle inhibition (AMI). Whole-body vibration (WBV) has the potential to address the neurophysiologic deficits accompanied by CAI and, therefore, possibly prevent reinjury. OBJECTIVE: To determine if an acute bout of WBV can improve AMI and proprioception in individuals with CAI. DESIGN AND PARTICIPANTS: The authors examined if an acute bout of WBV can improve AMI and proprioception in individuals with CAI with a repeated-measures design. A total of 10 young adults with CAI and 10 age-matched healthy controls underwent a control, sham, and WBV condition in randomized order. SETTING: Biomechanics laboratory. INTERVENTION: WBV. MAIN OUTCOME MEASURES: Motoneuron pool recruitment was assessed via Hoffmann reflex (H-reflex) in the soleus. Proprioception was evaluated using ankle joint position sense at 15° and 20° of inversion. Both were assessed prior to, immediately following, and 30 minutes after the intervention (pretest, posttest, and 30mPost, respectively). RESULTS: Soleus maximum H-reflex:M-response (H:M) ratios were 25% lower in the CAI group compared with the control group (P = .03). Joint position sense mean constant error did not differ between groups (P = .45). Error at 15° in the CAI (pretest 0.8 [1.6], posttest 2.0 [2.8], 30mPost 2.0 [1.9]) and control group (pretest 0.8 [2.0], posttest 0.6 [2.9], 30mPost 0.5 [2.1]) did not improve post-WBV. Error at 20° did not change post-WBV in the CAI (pretest 1.3 [1.7], posttest 1.0 [2.4], 30mPost 1.5 [2.2]) or control group (pretest -0.3 [3.0], posttest 0.8 [2.1], 30mPost 0.6 [1.8]). CONCLUSION: AMI is present in the involved limb of individuals with CAI. The acute response following a single bout of WBV did not ameliorate the presence of AMI nor improve proprioception in those with CAI.

Developing reliable measures of the passive torque-angle relationship for shoulder internal and external rotation: Implications for overhead athletics.

OBJECTIVES: 1) Thoroughly assess shoulder flexibility by establishing the passive torque-angle relationship for internal and external rotation with the arm in an overhead athletics position (abducted 90°) and 2) test the reliability of four passive torque-angle measures. DESIGN: Reliability study. SETTING: Data were collected in a university biomechanics laboratory. PARTICIPANTS: Bilateral shoulder flexibility of 15 male college students (20.7 ±â€¯1.1 y) was evaluated twice in two sessions over 7-10 days. MAIN OUTCOME MEASURES: For both ER and IR, reliability was assessed bilaterally (intra-session, inter-session, and inter-tester) for the traditional range of motion measure and three novel kinetic measures: torque at end ROM, resistance onset angle, rotational stiffness. This resulted in 48 total assessments. RESULTS: Thirty-four assessments had good to excellent reliability (ICC ≥ 0.8), 10 had fair reliability (0.7 ≤ ICC < 0.8), and 4 had poor reliability (ICC< 0.7). Three of the four flexibility measures had a good overall ICC score: ROM (0.83), torque at end ROM (0.84), and resistance onset angle (0.81). The fourth, stiffness, had a fair overall reliability score (0.74). CONCLUSIONS: The passive torque-angle measures should be assimilated into clinical and research settings to determine the relevance to injury, rehabilitation, and performance.

The effect of wheelchair propulsion style on changes in time spent in extreme wrist orientations after a bout of fatiguing propulsion.

This study compared how wheelchair propulsion styles affect changes in percentage of time spent in extreme wrist orientations, which have been associated with median nerve injury, after a fatiguing bout of propulsion. Twenty novice, non-disabled adult males learned arcing (ARC) and semicircular (SEMI) propulsion styles and utilised each to perform a wheelchair fatigue protocol. ARC and SEMI did not significantly differ in terms of changes after the fatigue protocol in percentage of time spent in extreme flexion/extension or radial/ulnar deviation at the push phase beginning or end. A pattern was observed, although not significant, of greater increases in percentage of time spent in extreme wrist extension and ulnar deviation during the push phase beginning and ulnar deviation during the push phase end while utilising SEMI relative to ARC. This study evinces that individual differences are greater than observed changes in extreme wrist orientations for both propulsion styles. Practitioner Summary: How wheelchair propulsion styles change with fatigue in terms of extreme wrist orientations was examined. This study evinces that individual differences are greater than observed changes in extreme wrist orientations for both propulsion styles and point towards the need for future research on individual differences utilising propulsion styles.

Split-Belt Treadmill Walking Alters Lower Extremity Frontal Plane Mechanics.

Interventions that manipulate gait speed may also affect the control of frontal plane mechanics. Expanding the current knowledge of frontal plane adaptations during split-belt treadmill walking could advance our understanding of the influence of asymmetries in gait speed on frontal plane mechanics and provide insight into the breadth of adaptations required by split-belt walking (SBW). Thirteen young, healthy participants, free from lower extremity injury walked on a split-belt treadmill with belts moving simultaneously at different speeds. We examined frontal plane mechanics of the ankle, knee, and hip joints during SBW, as well as medio-lateral ground reaction forces (ML-GRF). We did not observe alterations in the frontal mechanics produced during early or late adaptation of SBW when compared to conditions where the belts moved together. We did observe that ML-GRF and hip moment impulse of the fast limb increased over time with adaptation to SBW. These results suggest this modality may provide a unique therapy for individuals with gait pathologies, impairments, or compensation(s).

The Effect of Propulsion Style on Wrist Movement Variability During the Push Phase After a Bout of Fatiguing Propulsion.

BACKGROUND: Wheelchair propulsion has been linked to overuse injuries regardless of propulsion style. Many aspects of the arcing (ARC) and semicircular (SEMI) propulsion styles have been compared, but differences in intracycle movement variability, which have been linked to overuse injuries, have not been examined. OBJECTIVE: To explore how ARC and SEMI affect changes in intracycle wrist movement variability after a fatiguing bout of propulsion. DESIGN: Repeated measures crossover design. SETTING: Wheelchair rollers and wheelchair fatigue course in a research laboratory. PARTICIPANTS: Twenty healthy, nondisabled adult men without previous wheelchair experience. INTERVENTIONS: Participants learned ARC and SEMI and used each to perform a wheelchair fatigue protocol. MAIN OUTCOME MEASUREMENTS: Thirty seconds of propulsion on rollers were recorded by motion-capture cameras before and after a fatigue protocol for each propulsion style on 2 testing days. Angular wrist orientations (flexion/extension and radial/ulnar deviation) and linear wrist trajectories (mediolateral direction) were computed, and intracycle movement variability was calculated as standard deviations of the detrended and filtered values during the push phase beginning and end. Paired samples t tests were used to compare ARC and SEMI based on the percent changes from pre- to postfatigue protocol. RESULTS: Both propulsion styles resulted in increased intracycle wrist movement variability postfatigue, but observed increases did not significantly differ between ARC and SEMI. CONCLUSIONS: This study evinces that intersubject variability exceeded average changes in intracycle wrist movement variability for both propulsion styles. Neither propulsion style resulting in a greater change in intracycle movement variability may suggest that no single propulsion style is ideal for everyone. The large intersubject variability may indicate that the propulsion style resulting in the smallest increase in intracycle movement variability after a fatiguing bout of propulsion may differ for each person and may help explain why wheelchair users self-select to use different propulsion styles.

Laterality of repetitive finger movement performance and clinical features of Parkinson's disease.

Impairments in acoustically cued repetitive finger movement often emerge at rates near to and above 2Hz in persons with Parkinson's Disease (PD) in which some patients move faster (hastening) and others move slower (bradykinetic). The clinical features impacting this differential performance of repetitive finger movement remain unknown. The purpose of this study was to compare repetitive finger movement performance between the more and less affected side, and the difference in clinical ratings among performance groups. Forty-one participants diagnosed with idiopathic PD completed an acoustically cued repetitive finger movement task while "on" medication. Eighteen participants moved faster, 10 moved slower, and 13 were able to maintain the appropriate rate at rates above 2Hz. Clinical measures of laterality, disease severity, and the UPDRS were obtained. There were no significant differences between the more and less affected sides regardless of performance group. Comparison of disease severity, tremor, and rigidity among performance groups revealed no significant differences. Comparison of posture and postural instability scores revealed that the participants that demonstrated hastening had worse posture and postural instability scores. Consideration of movement rate during the clinical evaluation of repetitive finger movement may provide additional insight into varying disease features in persons with PD.

Photobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner.

Photobiomodulation (PBM) therapy has been implicated as an effective ergogenic aid to delay the onset of muscle fatigue. The purpose of this study was to examine the dose-response ergogenic properties of PBM therapy and its ability to prolong time to task failure by enhancing muscle activity and delaying the onset of muscle fatigue using a static positioning task. Nine participants (24.3 ± 4.9 years) received three doses of near-infrared (NIR) light therapy randomly on three separate sessions (sham, 240, and 480 J). For the positioning task, participants held a 30 % one-repetition maximum (1-RM) load using the index finger until volitional fatigue. Surface electromyography (sEMG) of the first dorsal interosseous muscle was recorded for the length of the positioning task. Outcomes included time to task failure (TTF), muscle fatigue, movement accuracy, motor output variability, and muscle activity (sEMG). The 240-J dose significantly extended TTF by 26 % (p = 0.032) compared with the sham dose. TTF for the 240-J dose was strongly associated with a decrease in muscle fatigue (R (2) = 0.54, p = 0.024). Our findings show that a 240-J dose of NIR light therapy is efficacious in delaying the onset and extent of muscle fatigue during submaximal isometric positioning tasks. Our findings suggest that NIR light therapy may be used as an ergogenic aid during functional tasks or post-injury rehabilitation.

Adaptation Strategies of Individuals With Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Despite the strong implications for rehabilitation design, the capability of individuals with anterior cruciate ligament reconstruction (ACLR) to adapt and store novel gait patterns have not been well studied. PURPOSE: To investigate how reconstructive surgery may affect the ability to adapt and store novel gait patterns in persons with ACLR while walking on a split-belt treadmill. STUDY DESIGN: Controlled laboratory study. METHODS: Gait adaptation was compared between 20 participants with ACLR and 20 healthy controls during split-belt treadmill walking. Gait adaptation was assessed in slow- and fast-adapting parameters by (1) the magnitude of symmetry during late adaptation and (2) the amount of the asymmetry during de-adaptation. RESULTS: Healthy individuals adapted a new walking pattern and stored the new walking pattern equally in both the dominant and nondominant limbs. Conversely, individuals with ACLR displayed impairments in both slow-adapting and fast-adapting derived gait adaptation and significant differences in behavior between the reconstructed and uninjured limb. CONCLUSION: While surgical reconstruction and physical therapy are aimed at improving mechanical stability to the knee, the study data suggest that fundamental features of motor control remain altered. After ACLR, participants display an altered ability to learn and store functional gait patterns.

Repetitive finger movement performance differs among Parkinson's disease, Progressive Supranuclear Palsy, and spinocerebellar ataxia.

BACKGROUND: Differentiating movement disorders is critical for appropriate treatment, prognosis, and for clinical trials. In clinical trials this is especially important as effects can be diluted by inclusion of inappropriately diagnosed participants. In early disease duration phases, disorders often have overlapping clinical features, such as impairments in repetitive finger movement, making diagnosis challenging. The purpose of this pilot study was to examine and compare repetitive finger movement performance in participants diagnosed with idiopathic Parkinson's disease, Progressive Supranuclear Palsy, and spinocerebellar ataxias. METHODS: Participants completed an unconstrained index finger flexion/extension movement (i.e. finger tap) in time with an incremental acoustic tone. Measures of movement rate, movement amplitude, and coefficient of variation were compared among groups. RESULTS: Significant differences between groups were revealed for movement rate at faster tone rates. Participants with Parkinson's disease tended to tap faster than the tone rate while participants with Progressive Supranuclear Palsy and spinocerebellar ataxia tended to tap slower. No significant differences were revealed for movement amplitude, but participants with spinocerebellar ataxia demonstrated greater variance in amplitude than participants with Parkinson's disease. CONCLUSION: Quantitative analysis of repetitive finger movement performance at faster rates may be helpful to differentiate Parkinson's Disease, Progressive Supranuclear Palsy and spinocerebellar ataxia.

Low-frequency versus high-frequency subthalamic nucleus deep brain stimulation on postural control and gait in Parkinson's disease: a quantitative study.

BACKGROUND: High frequency stimulation (HFS) of the subthalamic nucleus (STN-DBS) has been shown to have little impact on postural control and gait improvements in Parkinson's disease (PD). There is a lack of consensus and quantitative evidence to suggest that stimulating STN at a lower frequency (LFS) as compared to HFS will be superior in improving symptoms. OBJECTIVE/HYPOTHESIS: To determine if postural control and gait characteristics of persons with PD improve at an LFS (60 Hz) compared to HFS (>100 Hz). We hypothesized that persons with PD would perform better on postural control and gait measures at LFS. METHODS: Nineteen participants with bilateral STN-DBS underwent UPDRS, static and dynamic postural control using gait initiation, and gait evaluations in three stimulation conditions (baseline voltage stable across conditions: OFF, LFS of 60 Hz, and HFS of >100 Hz). Additionally 10/19 participants were also stimulated at 30 Hz and 60 Hz and at higher voltages. A one-way ANOVA was performed to compare the conditions. RESULTS: Total UPDRS-III score, step length and velocity during gait initiation, and gait speed significantly improved during 60 Hz and >100 Hz conditions when compared to the OFF condition (P < 0.05). There were no significant differences between 60 Hz and >100 Hz conditions. Using LFS at higher voltage showed no improvement over >100 Hz condition. CONCLUSIONS: The positive effects of both LFS and HFS on postural control and gait were similar and clinical changes were relatively small. LFS may not help improve postural control, and gait particularly for persons with PD who do not develop gait-related disorders after HFS.

Near-infrared light therapy to attenuate strength loss after strenuous resistance exercise.

CONTEXT: Near-infrared (NIR) light therapy is purported to act as an ergogenic aid by enhancing the contractile function of skeletal muscle. Improving muscle function is a new avenue for research in the area of laser therapy; however, very few researchers have examined the ergogenic effects of NIR light therapy and the influence it may have on the recovery process during rehabilitation. OBJECTIVE: To evaluate the ergogenic effect of NIR light therapy on skeletal muscle function. DESIGN: Crossover study. SETTING: Controlled laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-nine healthy men (n = 21) and women (n = 18; age = 20.0 ± 0.2 years, height = 169 ± 2 cm, mass = 68.4 ± 1.8 kg, body mass index = 23.8 ± 0.4 kg/m(2)). INTERVENTION(S): Each participant received active and sham treatments on the biceps brachii muscle on 2 separate days. The order of treatment was randomized. A class 4 laser with a cumulative dose of 360 J was used for the active treatment. After receiving the treatment on each day, participants completed an elbow-flexion resistance-exercise protocol. MAIN OUTCOME MEASURE(S): The dependent variables were elbow range of motion, muscle point tenderness, and strength (peak torque). Analysis of variance with repeated measures was used to assess changes in these measures between treatments at baseline and at follow-up, 48 hours postexercise. Additionally, immediate strength loss postexercise was compared between treatments using a paired t test. RESULTS: Preexercise to postexercise strength loss for the active laser treatment, although small, was less than with the sham treatment (P = .05). CONCLUSIONS: Applied to skeletal muscle before resistance exercise, NIR light therapy effectively attenuated strength loss. Therefore, NIR light therapy may be a beneficial, noninvasive modality for improving muscle function during rehabilitation after musculoskeletal injury. However, future studies using higher treatment doses are warranted.

Long-term deficits in quadriceps strength and activation following anterior cruciate ligament reconstruction.

OBJECTIVE: Even some time after a ruptured ACL has been reconstructed thigh musculature atrophy, voluntary activation, and knee-extensor strength deficits may be encountered. The purpose of this study was to evaluate bilateral knee-extension strength, voluntary activation of the quadriceps, and thigh circumference in males and females with ACL reconstruction (ACLR). DESIGN AND PARTICIPANTS: Within-subject and between-subject designs were used to evaluate 24 unilateral ACLR individuals and 23 controls. MAIN OUTCOME MEASURES: Isokinetic knee-extension strength was assessed in ACLR participants while central activation ratio (CAR) and thigh circumference measures were obtained from both groups. RESULTS: Knee-extensor strength deficits (p < .039) and lower CAR of the quadriceps were found in the ACLR limb compared to the uninvolved limb (p = .047). Extensor strength was greater in males (p < .001), however, CAR was not different between sexes (p = .086). No difference in voluntary activation was revealed among the ACLR limb, uninvolved limb, and control limb when compared as independent groups (p = .460). The strength deficits found in the ACLR limb are partly attributable to lower voluntary activation compared to the uninvolved leg, given that no difference was found in thigh circumference between legs. CONCLUSION: Clinicians should consider the deficits in muscle function when returning patients to pre-injury activity levels.

Cellular phone texting impairs gait in able-bodied young adults.

Cellular phone texting has become increasingly popular, raising the risk of distraction-related injuries. The purpose of this study was to compare alterations in gait parameters during normal gait as opposed to walking while texting. Thirty able-bodied young adults (age = 20 ± 2 y, height = 171 ± 40 cm, mass = 61.7 ± 11.2 kg) who reported texting on a regular basis were tested using an 11-camera optical motion capture system as they walked across an 8 m, obstacle-free floor. A reduction in velocity (P < .05) was seen along with additional significant changes in spatial and temporal parameters. Specifically, step width and double stance time increased, while toe clearance, step length, and cadence decreased. Although many of the changes in spatial and temporal parameters generally accompany slowed gait, the complex distraction task used here may have amplified these potentially deleterious effects. The combination of the slower gait velocity and decrease in attention to the surrounding environment suggests that an individual who is texting while walking could be at a greater risk of injury. Tripping injuries while texting could be more likely due to the decreased toe clearance. In addition, increased step width may increase the likelihood of stepping on an unstable surface or colliding with obstacles in close proximity.

Validation of a cardiorespiratory fitness assessment for firefighters.

Currently, a submaximal protocol is used to measure cardiorespiratory fitness in firefighters by estimating their true aerobic capacity (V[Combining Dot Above]O2max); however, this submaximal test has not been cross-validated among firefighters. Thirty firefighters (85% male, 15% female), completed the submaximal protocol and the maximal (Bruce) treadmill protocol on separate occasions. Pearson's correlation analyses between the submaximal and Bruce protocol revealed a significant moderate positive correlation (r = 0.635, p = 0.005). The range of mean V[Combining Dot Above]O2max values and SDs produced from the submaximal and maximal protocols varied greatly (35.4-50.9 vs. 28.6-58.4 ml·kg·min, and SD of 3.91 vs. 7.22, respectively). The submaximal V[Combining Dot Above]O2 test underestimated the true V[Combining Dot Above]O2max in the majority of firefighters (72.4%) and overestimated the true V[Combining Dot Above]O2max in the remainder of firefighters. Participants with a higher body fat percentage were more likely (p = 0.0157) to have an overestimated true V[Combining Dot Above]O2max than those with a lower-body fat percentage. Our results indicate the current submaximal V[Combining Dot Above]O2 test used to measure cardiorespiratory fitness in firefighters is an improvement over previous protocols. However, our findings also show that the accuracy of this submaximal test for predicting the true V[Combining Dot Above]O2max in firefighters is questionable, and may not identify firefighters who possess substandard cardiorespiratory fitness, particularly in those with a higher percentage of body fat. Thus, the results of this study indicate that improvements to the current Fire Service Joint Management, Wellness & Fitness Initiative (WFI) V[Combining Dot Above]O2 assessment is still needed to accurately reflect the true V[Combining Dot Above]O2max of individual firefighters.

Comparison of metabolic cost, performance, and efficiency of propulsion using an ergonomic hand drive mechanism and a conventional manual wheelchair.

OBJECTIVE: To compare the metabolic cost (oxygen uptake per unit time [V˙o2 consumption], heart rate, and number of pushes), performance (velocity and distance traveled), and efficiency (oxygen uptake per distance traveled [Vo2 efficiency]) of propulsion using a novel ergonomic hand drive mechanism (EHDM) and a conventional manual wheelchair (CMW). DESIGN: Repeated-measures crossover design. SETTING: Semicircular track. PARTICIPANTS: Adult full-time manual wheelchair users with spinal cord injuries (N=12; mean age ± SD, 38.8±12.4y; mean body mass ± SD, 73.7±13.3kg; mean height ± SD, 173.6±11.1cm) who were medically and functionally stable and at least 6 months postinjury. INTERVENTION: Participants propelled themselves for 3.5 minutes at a self-selected pace in a CMW and in the same chair fitted with the EHDM. MAIN OUTCOME MEASURES: Velocity, distance traveled, number of pushes, V˙o2 consumption, Vo2 efficiency, and heart rate were compared by wheelchair condition for the last 30 seconds of each trial using paired t tests (α=.01). RESULTS: The CMW condition resulted in more distance traveled (33.6±10.8m vs 22.4±7.8m; P=.001), greater velocity (1.12±0.4m/s vs .75±.30m/s; P=.001), and better Vo2 efficiency (.10±.03mL·kg(-1)·m(-1) vs .15±.03mL·kg(-1)·m(-1); P<.001) than the EHDM condition, respectively. No significant differences were found between the 2 conditions for number of pushes (27.5±5.7 vs 25.7±5.4; P=.366), V˙o2 consumption (6.43±1.9mL·kg(-1)·min(-1) vs 6.19±1.7mL·kg(-1)·min(-1); P=.573), or heart rate (100.5±14.5 beats per minute vs 97.4±20.2 beats per minute; P=.42). CONCLUSIONS: The results demonstrate that metabolic costs did not differ significantly; however, performance and efficiency were sacrificed with the EHDM. Modifications to the EHDM (eg, addition of gearing) could rectify the performance and efficiency decrements while maintaining similar metabolic costs. Although not an ideal technology, the EHDM can be considered as an alternative mode of mobility by wheelchair users and rehabilitation specialists.

Wheelchair ergonomic hand drive mechanism use improves wrist mechanics associated with carpal tunnel syndrome.

Among conventional manual wheelchair (CMW) users, 49% to 63% experience carpal tunnel syndrome (CTS) that is likely induced by large forces transmitted through the wrist and extreme wrist orientations. The ergonomic hand drive mechanism (EHDM) tested in this study has been shown to utilize a more neutral wrist orientation. This study evaluates the use of an EHDM in terms of wrist orientations that may predispose individuals to CTS. Eleven adult full-time CMW users with spinal cord injury participated. Motion data were captured as participants propelled across a flat surface, completing five trials in a CMW and five trials in the same CMW fitted with the EHDM. Average angular wrist orientations were compared between the two propulsion styles. Use of the EHDM resulted in reduced wrist extension and ulnar deviation. The shift to more neutral wrist orientations observed with EHDM use may reduce median nerve compression.