In-office Maximal Voluntary Ventilation Testing Demonstrates Pulmonary Improvement Following Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

OBJECTIVE: Pulmonary function can be impaired in patients with adolescent idiopathic scoliosis (AIS). Maximal voluntary ventilation (MVV) has been shown to be more strongly correlated with major coronal curve, and a more easily obtained measurement of pulmonary function, than forced vital capacity (FVC). We evaluated changes in pulmonary function using these 2 measures in patients with AIS in relation to changes in major coronal curves over time. METHODS: Forty-seven patients with AIS with thoracic curves ≥10 degrees performed pulmonary function tests using the Carefusion MicroLoop Spirometer at enrollment and 1 year later. Major coronal curve worsening >5 degrees was considered curve progression. RESULTS: At enrollment, 47 patients had a mean major coronal curve of 38 degrees (range: 10 to 76 degrees). One year later, 17 patients had undergone posterior spinal fusion, 9 had curve progression >5 degrees, and 21 had no progression. MVV and major coronal curve were negatively correlated (r = -0.36, P = 0.01) at enrollment. After fusion, the major coronal curve improved by a mean of 41 degrees, and MVV improved by 23% (P < 0.01), but FVC did not improve significantly (6%, P = 0.29). In stable curves, MVV improved 12% (P = 0.01) and FVC improved 9% (P = 0.007). In patients without surgery whose curves progressed an average of 11 degrees, there was no significant change in MVV or FVC (P > 0.44). CONCLUSION: This is the first study using office-based spirometry in an orthopaedic clinic showing improved pulmonary function with posterior spinal fusion and growth in patients with AIS. It is notable that MVV improved after spinal fusion, but FVC did not, as MVV appears to be a more sensitive measurement for the assessment of pulmonary function in these patients. LEVEL OF EVIDENCE: Level II.

Abnormal Pulmonary Function in Early Parkinson's Disease: A Preliminary Prospective Observational Study.

Early Parkinson's disease (PD) may cause respiratory dysfunction; however the findings vary among studies. The aim of the preliminary prospective observational study was to explore the deterioration of pulmonary function at various stages in patients with early PD. A total of 237 patients with PD were screened. Fifty-six patients were included (modified Hoehn and Yahr stage ≤ 2.5). In addition, 56 age-matched healthy controls were also included in the study. Significant differences between the PD and control groups were found in all the investigated lung-function parameters. The maximal voluntary ventilation (MVV) percent predicted was the only parameter that distinguished PD stages (101.1 ± 14.9% vs. 82.8 ± 19.2% vs. 71.4 ± 12.9%, Hoehn and Yahr stages 1.5 vs. 2 vs. 2.5, respectively; p < 0.005). MVV could be the most sensitive parameter for distinguishing the severity of early-stage PD.

Evaluation of the ventilatory effects on human subjects in prolonged hip-flexed/head-down restraint position.

BACKGROUND: The restraint chair is a tool used by law enforcement and correction personnel to control aggressive, agitated individuals. When initiating its use, subjects are often placed in a hip-flexed/head-down (HFHD) position to remove handcuffs. Usually, this period of time is less than two minutes but can become more prolonged in particularly agitated patients. Some have proposed this positioning limits ventilation and can result in asphyxia. The aim of this study is to evaluate if a prolonged HFHD restraint position causes significant ventilatory compromise. METHODS: Subjects exercised on a stationary bicycle until they reached 85% of their predicted maximal heart rate. They were then handcuffed with their hands behind their back and placed into a HFHD seated position for five minutes. The primary outcome measurement was maximal voluntary ventilation (MVV). This was measured at baseline, after initial placement into the HFHD position, and after five minutes of being in the position while still maintaining the HFHD position. Baseline measurements were compared with final measurements for statistically significant differences. RESULTS: We analyzed data for 15 subjects. Subjects had a mean MVV of 165.3 L/min at baseline, 157.8 L/min after initially being placed into the HFHD position, and a mean of 138.7 L/min after 5 min in the position. The mean baseline % predicted MVV was 115%; after 5 min in the HFHD position the mean was 96%. This 19% absolute difference was statistically significant (p = 0.001). CONCLUSIONS: In healthy seated male subjects with recent exertion, up to five minutes in a HFHD position results in a small decrease in MVV compared with baseline MVV levels. Even with this decrease, mean MVV levels were still 96% of predicted after five minutes. Though a measurable decrease was found, there was no clinically significant change that would support that this positioning would lead to asphyxia over a five-minute time period.

Effects of a Progressive Stabilization Exercise Program Using Respiratory Resistance for Patients with Lumbar Instability: A Randomized Controlled Trial.

BACKGROUND This study investigated the effects of progressive stabilization exercise program carried out with respiratory resistance in patients with lumbar instability. MATERIAL AND METHODS Forty-three patients with lumbar instability were randomly assigned to experimental (n=20) and control groups (n=23). The experimental group performed progressive lumbar stabilization exercises along with respiratory resistance, and the control group only performed progressive lumbar stabilization exercises, for 40 min per session, 3 sessions a week, for 4 weeks. Numeric rating scale (NRS), Korean-Oswestry disability index (K-ODI), static balance ability, Fear-Avoidance Beliefs Questionnaire (FABQ), and pulmonary function test (PFT) were performed before and after the intervention program for comparison. RESULTS The 2 groups showed significant differences in NRS, K-ODI, balance ability, and FABQ after the interventions (p<0.05), but greater improvements were shown by the experimental group in balance ability and FABQ values. PFT results in the experimental group showed a significant increase (p<0.05) in forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and maximum voluntary ventilation (MVV). The experimental group showed a greater improvement (p<0.05) in FVC and MVV compared to the control group. CONCLUSIONS Progressive stabilization exercise program with respiratory resistance is an effective method with clinical significance in pain reduction, psychosocial stability, and enhancement of motor and respiratory functions.

Static and Dynamic Lung Volumes in Swimmers and Their Ventilatory Response to Maximal Exercise.

PURPOSE: While the static and dynamic lung volumes of active swimmers is often greater than the predicted volume of similarly active non-swimmers, little is known if their ventilatory response to exercise is also different. METHODS: Three groups of anthropometrically matched male adults were recruited, daily active swimmers (n = 15), daily active in fields sport (Rugby and Football) (n = 15), and recreationally active (n = 15). Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximal voluntary ventilation (MVV) was measured before and after exercise to volitional exhaustion. RESULTS: Swimmers had significantly larger FVC (6.2 ± 0.6 l, 109 ± 9% pred) than the other groups (5.6 ± 0.5 l, 106 ± 13% pred, 5.5 ± 0.8, 99% pred, the sportsmen and recreational groups, respectively). FEV1 and MVV were not different. While at peak exercise, all groups reached their ventilatory reserve (around 20%), the swimmers had a greater minute ventilation rate than the recreational group (146 ± 19 vs 120 ± 87 l/min), delivering this volume by breathing deeper and slower. CONCLUSIONS: The swimmers utilised their larger static volumes (FVC) differently during exercise by meeting their ventilation volume through long and deep breaths.

Reliability and Validity of a Pool-Based Maximal Oxygen Uptake Test to Examine High-Intensity Short-Duration Freestyle Swimming Performance.

Nagle, EF, Nagai, T, Beethe, AZ, Lovalekar, MT, Zera, JN, Connaboy, C, Abt, JP, Beals, K, Nindl, BC, Robertson, RJ, and Lephart, SM. Reliability and validity of a pool-based maximal oxygen uptake test to examine high-intensity short-duration freestyle swimming performance. J Strength Cond Res 33(5): 1208-1215, 2019-A modality-specific swimming protocol to assess maximal oxygen uptake (V[Combining Dot Above]O2maxsw) is essential to accurately prescribe and monitor swimming conditioning programs. Consequently, there is a need for a reliable and valid graded intensity swimming pool test to accurately assess V[Combining Dot Above]O2maxsw using indirect calorimetry. The purpose of this study was to assess (a) reliability of an intensity self-regulated swimming pool test of V[Combining Dot Above]O2maxsw and (b) validity of a V[Combining Dot Above]O2maxsw test using performance swim (PS) time as the criterion. Twenty-nine men (n = 15) and women (n = 14) (age, 23 ± 6.4 years; body mass index, 23.5 ± 3.0 kg·m) performed 2 swimming pool V[Combining Dot Above]O2maxsw trials (V[Combining Dot Above]O2maxsw A and V[Combining Dot Above]O2maxsw B), and 2 PS tests (45.7 m [31.20 ± 4.5 seconds] and 182 m [159.2 ± 25.5 seconds]). For test-retest reliability (trials A vs. B), strong correlations (p < 0.05) were found for V[Combining Dot Above]O2maxsw (ml·kg·min) (r = 0.899), O2 pulse (ml O2·beat) (r = 0.833), and maximum expired ventilatory volume (L·min) (r = 0.785). For performance validity, moderately strong correlations (p < 0.05) were found between V[Combining Dot Above]O2maxsw A and 45.7-m (r = -0.543) and 182-m (r = -0.486) swim times. The self-regulated graded intensity swimming pool protocol examined presently is a reliable and valid test of V[Combining Dot Above]O2maxsw. Studies should consider the suitability of a V[Combining Dot Above]O2maxsw test for military personnel, clinical populations, and injured athletes.

Improvements of Shooting Performance in Adolescent Air Rifle Athletes After 6-Week Balance and Respiration Training Programs.

CONTEXT: Several factors, such as balance and respiration training programs, have been identified as contributing to a shooting performance. However, little is known about the benefits of these programs on the shooting records of adolescent air rifle athletes. OBJECTIVE: The purpose of this study was to investigate whether balance and respiration training can contribute to the shooting performance required for adolescent air rifle shooting athletes. DESIGN: Case-control study. SETTING: Shooting range. PARTICIPANTS: A total of 21 adolescent air rifle athletes were recruited from the local school community and assigned to an experimental (n = 11; EG) or control (n = 10; CG) group. INTERVENTION: The EG performed respiration and balance training for 30 minutes 3 times a week for 6 weeks, and the CG performed balance training only. MAIN OUTCOME MEASURES: Data were collected on the respiratory function, muscle activity, and shooting record before and after the 6-week intervention. RESULTS: The forced vital capacity (FVC), forced expired volume in 1 second (FEV1), FEV1 as a percentage of FVC, peak expiratory flow, and maximum voluntary ventilation were significantly increased in the EG, and FEV1 as a percentage of FVC was significantly increased in the CG (P < .05). The FVC and peak expiratory flow postintervention were significantly different between the groups (P < .05). The activity of the right internal oblique (IO) and left IO muscles of the FVC were significantly different in the EG (P < .05). Within-group changes in right external oblique, right IO, and left IO of the maximum voluntary ventilation were significantly increased in the EG (P < .05). The right IO and left IO activity improved more significantly in the EG than CG (P < .05). There was no difference between the groups with respect to the shooting records. CONCLUSIONS: The clinical significance of this study is the balance and respiration training affected the respiration function capacity and muscle activity, but did not affect the shooting record. Nevertheless, these training are a potential approach method to improve athletes' shooting record.

Effect of a Respiratory Training Program Using Wind Instruments on Cardiopulmonary Function, Endurance, and Quality of Life of Elderly Women.

BACKGROUND Physical changes due to aging lead to weakening of respiratory muscles and decreased lung functions that result in increasing risk of chronic respiratory disease. A complex respiratory rehabilitation program is needed to prevent respiratory diseases and improve lung functions and quality of life. The purpose of the present study was to examine the effects of respiratory training programs on pulmonary functions, cardiovascular endurance, and quality of life in elderly women. MATERIAL AND METHODS The program was structured with respiration exercise and playing wind musical instruments for 10 weeks (n=13) and 5 weeks (n=16), respectively, for elderly women in 2 different community welfare centers. The program consisted of breathing exercises twice a week, 20 min per session, and 40 min of wind instrumentation. Effects were assessed using forced vital capacity (FVC), forced expiratory volume-one second (FEV1), FEV1/FVC ratio (FEV1%), maximum voluntary ventilation (MVV), 6-minute walk test (6MWT), modified Borg scale (MBS), and life satisfaction scale (LSS). RESULTS The 10-week program group (10WPG) showed significant differences in FVC, MVV, 6MWT, MBS, and LSS before and after interventions (p<.05), and the 5-week program group (5WPG) showed significant differences in FVC and 6MWT. MVV, MBS, and LSS were not significantly different between the 2 groups (p<.05). CONCLUSIONS This study confirms that the long-term respiration training program has positive effects on pulmonary functions, cardiopulmonary endurance, and quality of life. Various respiratory training programs and long-term implementations are needed to prevent respiratory illness and to improve lung functions and quality of life of respiratory patients.

Effect of altering breathing frequency on maximum voluntary ventilation in healthy adults.

BACKGROUND: Compared to other pulmonary function tests, there is a lack of standardization regarding how a maximum voluntary ventilation (MVV) maneuver is performed. Specifically, little is known about the variation in breathing frequency (fR) and its potential impact on the accuracy of test results. This study examines the effect of several preselected values for fR and one self-selected fR (fRself) on MVV. METHODS: Ten participants performed MVV maneuvers at various fR values, ranging from 50 to 130 breaths·min- 1 in 10 breaths·min- 1 intervals and at one fRself. Three identical trials with 2-min rest periods were conducted at each fR, and the sequence in which fR was tested was randomized. Ventilation and related parameters were measured directly by gas exchange analysis via a metabolic measurement system. RESULTS: A third-order polynomial regression analysis showed that MVV = - 0.0001(fR)3 + 0.0258(fR)2-1.38(fR) + 96.9 at preselected fR and increased up to approximately 100 breaths·min- 1 (r2 = 0.982, P < 0.001). Paired t-tests indicated that average MVV values obtained at all preselected fR values, but not fRself, were significantly lower than the average maximum value across all participants. A linear regression analysis revealed that tidal volume (VT) = - 2.63(MVV) + 300.4 at preselected fR (r2 = 0.846, P < 0.001); however, this inverse relationship between VT and MVV did not remain true for the self-selected fR. The VT obtained at this fR (90.9 ± 19.1% of maximum) was significantly greater than the VT associated with the most similar MVV value (at a preselected fR of 100 breaths·min- 1, 62.0 ± 10.4% of maximum; 95% confidence interval of difference: (17.5, 40.4%), P < 0.001). CONCLUSIONS: This study demonstrates the shortcomings of the current lack of standardization in MVV testing and establishes data-driven recommendations for optimal fR. The true MVV was obtained with a self-selected fR (mean ± SD: 69.9 ± 22.3 breaths·min- 1) or within a preselected fR range of 110-120 breaths·min- 1. Until a comprehensive reference equation is established, it is advised that MVV be measured directly using these guidelines. If an individual is unable to perform or performs the maneuver poorly at a self-selected fR, ventilating within a mandated fR range of 110-120 breaths·min- 1 may also be acceptable.

Influence of sex, menstrual cycle, and oral contraceptives on the cerebrovascular response to paced deep breathing.

PURPOSE: Deep breathing assesses autonomic function; however, many researchers/clinicians do not account for hyperventilation, brain blood flow or blood pressure. METHODS: Men and women (with/without oral contraceptives) participated. women participated during low and high hormone phases of the menstrual cycle. Blood pressure, end-tidal carbon dioxide, middle cerebral artery velocity and cerebrovascular resistance were assessed. RESULTS: Deep breathing decreased end-tidal carbon dioxide and middle cerebral artery velocity while increasing cerebrovascular resistance in all participants; blood pressure decreased in men. There were no influences of menstrual cycle or oral contraceptives. CONCLUSIONS: Men have different autonomic responses to deep breathing compared to women.

Longitudinal analysis of endurance and respiratory function from a natural history study of Morquio A syndrome.

OBJECTIVES: Baseline data from the Morquio A Clinical Assessment Program (MorCAP) revealed that individuals with Morquio A syndrome show substantial impairment in multiple domains including endurance and respiratory function (Harmatz et al., Mol Genet Metab, 2013). Here, 1- and 2-year longitudinal endurance and respiratory function data are presented. METHODS: Endurance was assessed using the 6-minute walk test (6MWT) and the 3-minute stair climb test (3MSCT). Respiratory function was evaluated by measuring forced vital capacity (FVC) and maximum voluntary ventilation (MVV). Data were analyzed using repeated measures ANCOVA models. Annualized estimates of change were determined using model estimates and interpolation. RESULTS: 353, 184, and 78 subjects were assessed at Year 0 (baseline), Year 1, and Year 2, respectively. The overall annualized estimate of change (SE) in 6MWT distance was -4.86±3.25m; a larger decline of -6.84±5.38m was observed in the subset of subjects meeting the inclusion/exclusion criteria of the Phase 3 clinical trial of elosulfase alfa (≥5years of age with baseline 6MWT distance ≥30 and ≤325m). In contrast, little change (-0.14±0.60stairs/min) was observed in 3MSCT. Annualized changes (SE) in FVC and MVV were 2.44±0.68% and 1.01±2.38%, respectively. FVC and MVV increased in patients aged ≤14years, but decreased in older patients. CONCLUSIONS: The natural history of Morquio A syndrome is characterized by progressive impairment of endurance as measured by the 6MWT. Longitudinal trends in FVC and MVV showing increase in younger patients, but decrease in older patients, are likely to be influenced by growth. Changes in 6MWT may represent a sensitive measure of disease progression in ambulatory Morquio A patients.

Multi-domain impact of elosufase alfa in Morquio A syndrome in the pivotal phase III trial.

OBJECTIVE: To report and discuss the multi-domain impact of elosulfase alfa, with focus on tertiary and composite endpoints, in the 24-week, randomized, double-blind, placebo-controlled phase 3 trial in patients with Morquio A syndrome (mucopolysaccharidosis IVA). METHODS: Patients with Morquio A syndrome aged ≥5 years were randomized 1:1:1 to elosulfase alfa 2.0mg/kg/week (qw; N=58), elosulfase alfa 2.0mg/kg/every other week (qow; N=59), or placebo (N=59) for 24 weeks. Primary and secondary efficacy measures were 6-minute walk test (6MWT; primary), 3-minute stair climb test (3-MSCT) and urinary keratan sulfate (KS). Safety was also evaluated. Tertiary efficacy measures included respiratory function measures, activities of daily living (MPS Health Assessment Questionnaire [MPS-HAQ]), anthropometric, echocardiographic and radiographic measures, hearing and corneal clouding assessment. In order to fully characterize treatment impact in this heterogeneous disorder, the effect of elosulfase alfa on composite efficacy measures was evaluated as well. RESULTS: The study was not designed to have sufficient power for any of the tertiary outcomes. For most tertiary endpoints, subjects treated with the weekly dose of elosulfase alfa improved more than those receiving placebo. The largest treatment effects were seen in maximal voluntary ventilation (MVV), MPS-HAQ, height, and growth rate. The qow group appeared similar to placebo. The analysis of a pre-specified composite endpoint (combining changes from baseline in 6MWT, 3MSCT and MVV z-scores equally weighted) showed a modest positive impact of elosulfase alfa qw versus placebo group (P=0.053). As a pre-specified supportive analysis, the O'Brien Rank Sum composite endpoint (changes from baseline in 6MWT, 3MSC, and MVV), analysis also showed that the qw group performed better than the placebo group (P=0.011). In post-hoc analyses, combinations of other endpoints were also explored using the O'Brien Rank Sum test and showed statistically significant differences between elosulfase alfa qw and placebo favoring elosulfase alfa qw. Differences between elosulfase alfa qow and placebo were not statistically significant. Positive changes were observed in most tertiary variables, demonstrating the efficacy of weekly treatment with elosulfase alfa. CONCLUSIONS: Treatment with weekly elosulfase alfa led to improvements across most efficacy measures, resulting in clinically meaningful benefits in a heterogeneous study population.

The Effects of Game-Based Breathing Exercise on Pulmonary Function in Stroke Patients: A Preliminary Study.

BACKGROUND: Reduction of respiratory function along with hemiparesis leads to decreased endurance, dyspnea, and increased sedentary behavior, as well as to an increased risk of stroke. The main purpose of this study was to investigate the preliminary effects of game-based breathing exercise (GBE) on pulmonary function in stroke patients. MATERIAL AND METHODS: Thirty-eight in-patients with stroke (22 men, 16 women) were recruited for the study. Participants were randomly allocated into 2 groups: patients assigned to the GBE group (n=19), and the control group (n=19). The GBE group participated in a GBE program for 25 minutes a day, 3 days a week, during a 5 week period. For the same period, both groups participated in a conventional stroke rehabilitation program. Forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), FEV1/FVC, and maximum voluntary ventilation (MVV) were measured by a spirometer in pre- and post-testing. RESULTS: The GBE group had significantly improved FVC, FEV1, and MVV values compared with the control group (p<0.05), although there was no significant difference in FEV1/FVC value between groups. Significant short-term effects of the GBE program on pulmonary function in stroke patients were recorded in this study. CONCLUSIONS: These findings gave some indications that it may be feasible to include GBE in rehabilitation interventions with this population.

Changes in lung function during an extreme mountain ultramarathon.

This study aimed to assess the effects of an extreme mountain ultramarathon (MUM, 330 km, 24,000 D+) on lung function. Twenty-nine experienced male ultramarathon runners performed longitudinally [before (pre), during (mid), and immediately after (post) a MUM] a battery of pulmonary function tests. The tests included measurements of forced vital capacity, forced expiratory volume in 1 s, peak flow, inspiratory capacity, and maximum voluntary ventilation in 12 s (MVV12). A significant reduction in the running speed was observed (-43.0% between pre-mid and mid-post; P < 0.001). Expiratory function declined significantly at mid (P < 0.05) and at post (P < 0.05). A similar trend was observed for inspiratory function (P < 0.05). MVV12 declined at mid (P < 0.05) and further decreased at post (P < 0.05). Furthermore, there are significant negative correlations between performance time and MVV12 pre-race (R = -0.54, P = 0.02) as well as changes in MVV12 between pre- and post-race (R = -0.53, P = 0.009). It is concluded that during an extreme MUM, a continuous decline in pulmonary function was observed, likely attributable to the high levels of ventilation required during this MUM in a harsh mountainous environment.

Respiratory muscle training on pulmonary and swallowing function in patients with Huntington's disease: a pilot randomised controlled trial.

OBJECTIVE: To examine the effects of 4-month of respiratory muscle training on pulmonary and swallowing function, exercise capacity and dyspnoea in manifest patients with Huntington's disease. DESIGN: A pilot randomised controlled trial. SETTING: Home based training program. PARTICIPANTS: Eighteen manifest Huntington's disease patients with a positive genetic test and clinically verified disease expression, were randomly assigned to control group (n=9) and training group (n=9). INTERVENTION: Both groups received home-based inspiratory (5 sets of 5 repetitions) and expiratory (5 sets of 5 repetitions) muscle training 6 times a week for 4 months. The control group used a fixed resistance of 9 centimeters of water, and the training group used a progressively increased resistance from 30% to 75% of each patient's maximum respiratory pressure. MAIN MEASURES: Spirometric indices, maximum inspiratory pressure, maximum expiratory pressure, six minutes walk test, dyspnoea, water-swallowing test and swallow quality of life questionnaire were assessed before, at 2 and 4 months after training. RESULTS: The magnitude of increases in maximum inspiratory (d=2.9) and expiratory pressures (d=1.5), forced vital capacity (d=0.8), forced expiratory volume in 1 second (d=0.9) and peak expiratory flow (d=0.8) was substantially greater for the training group in comparison to the control group. Changes in swallowing function, dyspnoea and exercise capacity were small (d ≤ 0.5) for both groups without substantial differences between groups. CONCLUSIONS: A home-based respiratory muscle training program appeared to be beneficial to improve pulmonary function in manifest Huntington's disease patients but provided small effects on swallowing function, dyspnoea and exercise capacity.

Effect of added mass on treadmill performance and pulmonary function.

Military personnel engage in strenuous physical activity and load carriage. This study evaluated the role of body mass and of added mass on aerobic performance (uphill treadmill exercise) and pulmonary function. Performance on a traditional unloaded run test (4.8 km) was compared with performance on loaded tasks. Subjects performed an outdoor 4.8-km run and 4 maximal treadmill tests wearing loads of 0, 10, 20, and 30 kg. Subjects' pulmonary function (forced expired volume in 1 second [FEV1], forced vital capacity [FVC], and maximal voluntary ventilation [MVV]) was tested with each load, and peak values of heart rate, oxygen consumption ((Equation is included in full-text article.)), ventilation (VE), and respiratory exchange ratio (RER) were measured during each treadmill test. Performance on the 4.8-km run was correlated with treadmill performance, measured as time to exhaustion (TTE), with the strength of the correlation decreasing with load (r = 0.87 for 0 kg to 0.76 for 30 kg). Body mass was not correlated with TTE, other than among men with the 30-kg load (r = 0.48). During treadmill exercise, all peak responses other than RER decreased with load. Pulmonary function measures (FEV1, FVC, and MVV) decreased with load. Body mass was poorly correlated with treadmill performance, but added mass decreased performance. The decreased performance may be in part because of decreased pulmonary function. Unloaded 4.8-km run performance was correlated to unloaded uphill treadmill performance, but less so as load increased. Therefore, traditional run tests may not be an effective means of evaluating aerobic performance for military field operations.

Motor function and respiratory capacity in patients with late-onset pompe disease.

INTRODUCTION: The relationship between skeletal muscle strength and respiratory dysfunction in Pompe disease has not been examined by quantitative methods. We investigated correlations among lower extremity proximal muscle strength, respiratory function, and motor performance. METHODS: Concentric strength of the knee extensor and flexor muscles was measured with a dynamometer, and pulmonary function was evaluated using spirometry in 7 adult patients. The 6-minute walk test and the 4-step stair-climb test were used for assessing aerobic endurance and anaerobic power, respectively. RESULTS: Anaerobic motor performance correlated with strength of both thigh muscles. Respiratory function did not correlate with either muscle strength or motor function performance. CONCLUSIONS: Respiratory and lower extremity proximal muscles could be affected differentially by the disease in individual patients. Motor performance is influenced by thigh muscle strength and is less dependent of respiratory capacity in our cohort of ambulatory patients.

Effect of eccentric versus concentric exercise training on mitochondrial function.

INTRODUCTION: The effect of eccentric (ECC) versus concentric (CON) training on metabolic properties in skeletal muscle is understood poorly. We determined the responses in oxidative capacity and mitochondrial H2 O2 production after eccentric (ECC) versus concentric (CON) training performed at similar mechanical power. METHODS: Forty-eight rats performed 5- or 20-day eccentric (ECC) or concentric (CON) training programs. Mitochondrial respiration, H2 O2 production, citrate synthase activity (CS), and skeletal muscle damage were assessed in gastrocnemius (GAS), soleus (SOL) and vastus intermedius (VI) muscles. RESULTS: Maximal mitochondrial respiration improved only after 20 days of concentric (CON) training in GAS and SOL. H2 O2 production increased specifically after 20 days of eccentric ECC training in VI. Skeletal muscle damage occurred transiently in VI after 5 days of ECC training. CONCLUSIONS: Twenty days of ECC versus CON training performed at similar mechanical power output do not increase skeletal muscle oxidative capacities, but it elevates mitochondrial H2 O2 production in VI, presumably linked to transient muscle damage.

Why exercise capacity does not improve after pulmonary valve replacement.

Optimal timing of pulmonary valve replacement (PVR) for pulmonary regurgitation is a debated topic. It is logical that maximal aerobic capacity (VO2peak) would decline when a PVR is needed, but a diminished VO2peak is not always present before PVR, and previous studies show no improvement in VO2peak after PVR. This study aimed to evaluate changes in resting spirometry from pre- to post-PVR sternotomy, to determine the limiting factors of VO2peak before and after PVR, and to determine whether changes in resting lung function after PVR may explain the lack of improvement in VO2peak after surgery. For 26 patients (age, 19.7 ± 7.8 years) with a history of right ventricular outflow tract revision, the study prospectively evaluated echocardiograms, resting spirometry, and maximal exercise tests before PVR and then an average of 15 months after PVR. Flow volume loops were reviewed by a pulmonologist and categorized as obstructive, restrictive, both obstructive and restrictive, or normal. Exercise tests were interpreted using Eschenbacher's algorithm to determine the primary factors limiting exercise. No change in VO2peak or spirometry after PVR was observed. Before PVR, many patients had abnormal resting lung functions (85 % abnormal), which was unchanged after PVR (86 5 % abnormal). The majority of the patients had a ventilatory limitation to VO2peak before PVR (66.7 %), whereas 28.5 % had a cardiovascular limitation, and 4.8 % had no clear limitation. After PVR, 65.2 % of the patients had a ventilatory limitation, whereas 30.4 % had a cardiovascular limitation, and 4.4 % had no clear limitation to VO2peak. Pulmonary function did not change up to 15 months after surgical PVR. The frequency of pulmonary limitation to VO2peak after PVR did not increase. The effect of pulmonary function on exercise-related symptoms must be considered in this patient population. Improved cardiac hemodynamics are unlikely to improve VO2peak in a primarily pulmonary-limited patient.