Methods and protocols for incremental exercise testing in tetraplegia,using arm-crank ergometry assisted by Functional Electrical Stimulation

Cervical spinal cord injury (SCI) leads to tetraplegia, with paralysis and loss of sensation in the upper and lower limbs. The associated sedentary lifestyle results in an increased risk of cardiovascular disease. To address this, we require the design of exercise modalities aimed specifically at tetraplegia and methods to assess their efficacy.This paper describes methods for arm-crank ergometry (ACE) assisted by Functional Electrical Stimulation (FES) applied to the biceps and triceps. The instrumented ergometer enables work-rate control during exercise, implemented here for incremental exercise testing during FES-ACE. Detailed protocols for the tests are given.Experimental data collected during exercise tests with tetraplegic volunteers are provided to illustrate the feasibility of the proposed approach to testing and data analysis. Incremental tests enabled calculation of peak power output and peak oxygen uptake.We propose that the high-precision exercise testing protocols described here are appropriate to assess the efficacy of the novel exercise modality, FES-ACE, in tetraplegia.     

运动康复锻炼对冠心病经皮冠状动脉介入术后患者心肺功能及生活质量的影响

目的:探讨运动康复锻炼对冠心病经皮冠状动脉介入术(PCI)后患者心肺功能及生活质量的影响。方法:选取2016年10月-2018年4月期间我院收治的冠心病稳定性心绞痛患者80例,根据随机数字表法将患者分为对照组(n=40)和运动康复组(n=40),其中对照组给予常规康复运动,运动康复组在此基础上联合运动康复训练。比较两组患者术后12周的心肺功能指标,比较两组患者术前、术后2周、术后12周的6 min步行距离,比较两组患者术前、术后12周生活质量评分。结果:运动康复组患者术后12周峰值摄氧量、峰值通气量、峰值功率、每搏输出量、代谢当量以及摄氧效率斜率均高于对照组患者(P0.05)。两组患者术后2周、术后12周6 min步行距离均较术前增加,且运动康复组高于对照组(P0.05)。两组患者术后12周生理机能、生理职能、躯体疼痛、精神健康评分均较术前升高,且运动康复组高于对照组(P0.05);而两组患者术后12周社会功能、总体健康、精力、情感职能评分比较差异无统计学意义(P0.05)。结论:PCI术后患者给予运动康复锻炼,可显著提升患者生活质量,对患者心肺功能恢复具有较好的促进作用。     

Ⅱ期心脏康复方案对心脏瓣膜置换术患者心肺功能、运动耐力及生活质量的影响

摘要 目的：观察Ⅱ期心脏康复方案对心脏瓣膜置换术患者心肺功能、运动耐力及生活质量的影响。方法：选择自2018年3月到2021年3月期间我院接收的120例心脏瓣膜置换术患者,根据随机数字表法将患者分为对照组（60例,围术期常规康复干预）和观察组（60例,在对照组基础上给予Ⅱ期心脏康复方案）。观察两组运动耐力、心肺功能及生活质量,记录两组随访期间心血管不良事件发生率。结果：干预2个月后,两组峰值摄氧量（VO₂peak）、无氧阈时摄氧量（VO₂at）、无氧阈时代谢当量（METat）、氧脉搏（O₂pulse）均升高,且观察组高于对照组（P<0.05）。干预2个月后,两组Fugl-Meyer运动量表（FMA）评分升高、6 min步行试验距离（6MWT）增加,且观察组高于对照组（P<0.05）。干预2个月后,两组总体健康（GH）、生命活力（VT）、躯体疼痛（BP）、社会功能（SF）、心理健康（MH）、生理职能（RP）、生理功能（PF）、情感职能（RE）评分均升高,且观察组较对照组高（P<0.05）。与对照组比较,观察组心血管不良事件发生率降低（P<0.05）。结论：Ⅱ期心脏康复方案应用于心脏瓣膜置换术患者,可改善心肺功能,提高运动耐力及生活质量,降低心血管不良事件发生率。     

Comparison of Peak Cardiopulmonary Performance Parameters on a Robotics-Assisted Tilt Table,a Cycle and a Treadmill

Robotics-assisted tilt table (RATT) technology provides body support, cyclical stepping movement and physiological loading. This technology can potentially be used to facilitate the estimation of peak cardiopulmonary performance parameters in patients who have neurological or other problems that may preclude testing on a treadmill or cycle ergometer. The aim of the study was to compare the magnitude of peak cardiopulmonary performance parameters including peak oxygen uptake (VO_2peak) and peak heart rate (HR_peak) obtained from a robotics-assisted tilt table (RATT), a cycle ergometer and a treadmill. The strength of correlations between the three devices, test-retest reliability and repeatability were also assessed. Eighteen healthy subjects performed six maximal exercise tests, with two tests on each of the three exercise modalities. Data from the second tests were used for the comparative and correlation analyses. For nine subjects, test-retest reliability and repeatability of VO_2peak and HR_peak were assessed. Absolute VO_2peak from the RATT, the cycle ergometer and the treadmill was (mean (SD)) 2.2 (0.56), 2.8 (0.80) and 3.2 (0.87) L/min, respectively (p < 0.001). HR_peak from the RATT, the cycle ergometer and the treadmill was 168 (9.5), 179 (7.9) and 184 (6.9) beats/min, respectively (p < 0.001). VO_2peak and HR_peak from the RATT vs the cycle ergometer and the RATT vs the treadmill showed strong correlations. Test-retest reliability and repeatability were high for VO_2peak and HR_peak for all devices. The results demonstrate that the RATT is a valid and reliable device for exercise testing. There is potential for the RATT to be used in severely impaired subjects who cannot use the standard modalities.     

个体化心脏运动康复训练联合简式太极训练对稳定性慢性心力衰竭患者心肺功能、心理状态和生活质量的影响

摘要 目的：观察稳定性慢性心力衰竭（CHF）患者经简式太极训练联合个体化心脏运动康复训练后,患者心理状态、心肺功能和生活质量的变化情况。方法：选取2019年7月~2021年4月在我院接受治疗的102例稳定性CHF患者。根据随机数字表法分为对照组（常规治疗的基础上开展个体化心脏运动康复训练）和观察组（对照组的基础上增加简式太极训练）,各为51例。对比干预前后两组心肺功能、生活质量和心理状态。结果：干预后,两组峰值摄氧量(VO₂peak)、峰值心率升高,二氧化碳通气当量斜率(VE/VCO₂slope)下降（P<0.05）;观察组干预后VE/VCO₂slope低于对照组,峰值心率、VO₂peak高于对照组（P<0.05）。干预后,两组焦虑自评量表（SAS）、抑郁自评量表（SDS）评分下降（P<0.05）;观察组干预后SAS、SDS评分低于对照组（P<0.05）。干预后,两组症状、心理情绪、体力受限、社会受限评分及总分下降（P<0.05）;干预后观察组体力受限、心理情绪、社会受限、症状评分及总分较对照组低（P<0.05）。结论：个体化心脏运动康复训练联合简式太极训练可促进稳定性CHF患者心肺功能和心理状态改善,进而提高患者生活质量。     

缩唇腹式呼吸训练联合弹力带抗阻运动对慢性心力衰竭患者运动耐力、心肺功能及生活质量的影响

摘要 目的：观察缩唇腹式呼吸训练对联合弹力带抗阻运动对慢性心力衰竭（CHF）患者运动耐力、心肺功能及生活质量的影响。方法：选取2020年4月~2021年7月期间我院收治的CHF患者83例。按照双色球法将患者分为对照组（n=41）和观察组（n=42）,对照组接受弹力带抗阻运动,观察组接受缩唇腹式呼吸训练联合弹力带抗阻运动。观察两组运动耐力、心肺功能、生活质量及1年内再住院率和1年内死亡率情况。结果：两组干预4周后躯体领域评分、情绪领域评分、其他领域评分和总分均下降,且观察组低于对照组（P<0.05）。两组干预4周后用力肺活量（FVC）、第1秒用力呼气容积（FEV₁）、最大自主分钟通气量（MVV）、左室射血分数（LVEF）升高,且观察组高于对照组（P<0.05）,而左室舒张末期内径（LVEDD）、左室收缩末期内径（LVESD）下降,且观察组低于对照组（P<0.05）。两组干预4周后6 min步行距离试验（6MWT）、峰值摄氧量（VO_2peak ）及无氧阈值（AT）升高,且观察组高于对照组（P<0.05）。观察组的1年内再住院率、1年内死亡率均低于对照组（P<0.05）。结论：弹力带抗阻运动联合缩唇腹式呼吸训练可促进CHF患者心肺功能改善,提高运动耐力,促进生活质量提升,同时还可降低1年内再住院率、1年内死亡率,疗效较好。     

Peak power and pulmonary oxygen uptake during knee extension exercise – comparisons among different incremental protocols

Four incremental protocols of knee extension exercise of different stage durations were compared to study the effect of the protocol upon power output at the last stage (P _peak). Previous studies of knee extension have found very different power outputs with similar ergometers and these large differences have been interpreted as being the result of the fatigue due to the durations of the protocols. The knee extension device used in previous studies was modified to avoid the action of the knee and hip flexors: the subjects pushing on a lever instead of pulling a rod. In the present study five subjects performed four incremental knee extension exercises which differed with regard to stage duration (60, 90, 180 or 360 s) on this ergometer. The P _peak, peak oxygen uptake (V˙O_2peak) and peak heart rate (HR_peak) were measured at the end of each of these four incremental protocols. In eight subjects, the reliability of the protocols with the two shortest increments (60 and 90-s stages) was verified by measuring P _peak at 60 s and 90 s (P _peak60, P _peak90) twice. The knee ergometer proposed in the present paper was easy to use without any special training and should improve the measurement of P _peak. The P _peak60 [49.4 (SD 5.6) W] was higher than at 180 s [P _peak180, 43.6 (SD 5.8) W, P < 0.05] and at 360 s [P _peak360, 43.4 (SD 5.3) W, P < 0.05]. All the other differences in P _peak, V˙O_{2 peak} and HR_peak were not significant. All correlations between P _peak60, P _peak90, P _peak180 and P _peak360 were significant, except those between P _peak360 and P _peak90 or P _peak180. The effect of the stage duration on power output and oxygen uptake at the end of the knee extension exercises was not great. Consequently, the large differences in power output and oxygen uptake observed in previous studies cannot be explained by the protocol only. The significant difference between P _{peak 60} and P _peak90 was of the order of 10% in agreement with findings in the literature using cycle ergometry. The reliability of P _peak60 and P _peak90 was high and the use of these protocols can be recommended if further studies show that the measurement of P _peak, is useful in the evaluation of local endurance. Accepted: 2 April 1998     

Cardiopulmonary baroreflex is reset during dynamic exercise.

The purpose of this study was to examine the hypothesis that the operating point of the cardiopulmonary baroreflex resets to the higher cardiac filling pressure of exercise associated with the increased cardiac filling volumes. Eight men (age 26 +/- 1 yr; height 180 +/- 3 cm; weight 86 +/- 6 kg; means +/- SE) participated in the present study. Lower body negative pressure (LBNP) was applied at 8 and 16 Torr to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak oxygen uptake (104 +/- 20 W). Subsequently, two discrete infusions of 25% human serum albumin solution were administered until CVP was increased by 1.8 +/- 0.6 and 2.4 +/- 0.4 mmHg at rest and 2.9 +/- 0.9 and 4.6 +/- 0.9 mmHg during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, forearm blood flow and cardiac output were measured. During exercise, forearm vascular conductance increased from 7.5 +/- 0.5 to 8.7 +/- 0.6 U (P = 0.024) and total systemic vascular conductance from 7.2 +/- 0.2 to 13.5 +/- 0.9 l.min(-1).mmHg(-1) (P < 0.001). However, there was no significant difference in the responses of both forearm vascular conductance and total systemic vascular conductance to LBNP and the infusion of albumin between rest and exercise. These data indicate that the cardiopulmonary baroreflex had been reset during exercise to the new operating point associated with the exercise-induced change in cardiac filling volume.     

Cardiac output during exercise by the open circuit acetylene washin method: comparison with direct Fick.

An open-circuit (OpCirc) acetylene uptake cardiac output (QT) method was modified for use during exercise. Two computational techniques were used. OpCirc1 was based on the integrated uptake vs. end-tidal change in acetylene, and OpCirc2 was based on an iterative finite difference modeling method. Six subjects [28-44 yr, peak oxygen consumption (VO(2)) = 120% predicted] performed cycle ergometry exercise to compare QT using OpCirc and direct Fick methods. An incremental protocol was repeated twice, separated by a 10-min rest, and subsequently subjects exercised at 85-90% of their peak work rate. Coefficient of variation of the OpCirc methods and Fick were highest at rest (OpCirc1, 7%, OpCirc2, 12%, Fick, 10%) but were lower at moderate to high exercise intensities (OpCirc1, 3%, OpCirc2, 3%, Fick, 5%). OpCirc1 and OpCirc2 QT correlated highly with Fick QT (R(2) = 0.90 and 0.89, respectively). There were minimal differences between OpCirc1 and OpCirc2 compared with Fick up to moderate-intensity exercise (<70% peak VO(2)); however, both techniques tended to underestimate Fick at >70% peak VO(2). These differences became significant for OpCirc1 only. Part of the differences between Fick and OpCirc methods at the higher exercise intensities are likely related to inhomogeneities in ventilation and perfusion matching (R(2) = 0.36 for Fick - OpCirc1 vs. alveolar-to-arterial oxygen tension difference). In conclusion, both OpCirc methods provided reproducible, reliable measurements of QT during mild to moderate exercise. However, only OpCirc2 appeared to approximate Fick QT at the higher work intensities.     

功率自行车下肢亚极量运动对慢性阻塞性肺疾病康复影响的临床报告*

目的: 研究慢性阻塞性肺疾病（COPD）患者功率自行车下肢亚极量运动的康复治疗效果。方法: 30例门诊COPD患者随机分为康复组和对照组,每组15例,康复前后均完成常规肺功能（PFT）、心肺运动试验（CPET）、血气分析（ABG）、呼吸困难Borg评分和COPD患者自我评估测试问卷（CAT评分）,并比较前后变化。康复组采用功率自行车锻炼,以CPET80%峰值功率强度,每次运动30 min,每周3次,完成12周。结果: 康复组在康复后IC显著提高(P<0.01),peakW和peakVO₂也显著提高(P<0.01);Borg评分和CAT评分显著降低 (P<0.01)。末次运动持续时间较首次明显延长(P<0.01)。而对照组的这些指标均无显著改变(P>0.05)。两组在康复前后的PFT指标和血气分析等参数无明显变化。结论: COPD患者可以安全有效地进行运动康复治疗。功率自行车下肢亚极量运动康复能使COPD患者整体功能改善、运动时间延长、生活质量提高、患者获益。     

Effects of depletion exercise and light training on muscle glycogen supercompensation in men

Supercompensated muscle glycogen can be achieved by using several carbohydrate (CHO)-loading protocols. This study compared the effectiveness of two "modified" CHO-loading protocols. Additionally, we determined the effect of light cycle training on muscle glycogen. Subjects completed a depletion (D, n = 15) or nondepletion (ND, n = 10) CHO-loading protocol. After a 2-day adaptation period in a metabolic ward, the D group performed a 120-min cycle exercise at 65% peak oxygen uptake (VO2 peak) followed by 1-min sprints at 120% VO2 peak to exhaustion. The ND group performed only 20-min cycle exercise at 65% VO2 peak. For the next 6 days, both groups ate the same high-CHO diets and performed 20-min daily cycle exercise at 65% VO2 peak followed by a CHO beverage (105 g of CHO). Muscle glycogen concentrations of the vastus lateralis were measured daily with 13C magnetic resonance spectroscopy. On the morning of day 5, muscle glycogen concentrations had increased 1.45 (D) and 1.24 (ND) times baseline (P < 0.001) but did not differ significantly between groups. However, on day 7, muscle glycogen of the D group was significantly greater (p < 0.01) than that of the ND group (130 +/- 7 vs. 104 +/- 5 mmol/l). Daily cycle exercise decreased muscle glycogen by 10 +/- 2 (D) and 14 +/- 5 mmol/l (ND), but muscle glycogen was equal to or greater than preexercise values 24 h later. In conclusion, a CHO-loading protocol that begins with a glycogen-depleting exercise results in significantly greater muscle glycogen that persists longer than a CHO-loading protocol using only an exercise taper. Daily exercise at 65% VO2 peak for 20 min can be performed throughout the CHO-loading protocol without negatively affecting muscle glycogen supercompensation.     

经皮冠状动脉腔内血管成形术改变稳定性冠心病患者整体功能的临床研究*

目的: 应用症状限制极限负荷心肺运动试验（CPET）评估稳定性冠心病患者经皮冠状动脉腔内血管成形术（PCI）治疗前后的整体心肺功能变化。方法: 入选2014年8月至12月在本院经冠脉造影和心脏超声等检查诊断为稳定性冠心病患者59例,择期行PCI治疗31例（PCI组）,另单纯药物保守治疗28例为对照组。患者治疗前、后均进行CPET。结果: 所有患者均安全完成CPET,无任何并发症。药物对照组治疗前后所有功能指标均无明显变化（P>0.05）。PCI组治疗后仅无氧阈、峰值摄氧量和峰值氧脉搏比治疗前明显提高（P<0.05）,其他指标变化不显著（P>0.05）。CPET评估个体化分析发现PCI组治疗后升高（≥10%）峰值摄氧量和峰值氧脉搏比例明显高于对照组（P<0.05）。结论: PCI通过冠状动脉血运重建可明显改善患者心肺功能,提高运动能力。CPET是客观定量评估冠心病治疗效果的一种客观、定量、安全、有效方法。     

Fatty acid kinetics and carbohydrate metabolism during electrical exercise in spinal cord-injured humans

Motor center activity and reflexes from contracting muscle have been shown to be important for mobilization of free fatty acids (FFA) during exercise. We studied FFA metabolism in the absence of these mechanisms: during involuntary, electrically induced leg cycling in individuals with complete spinal cord injury (SCI). Healthy subjects performing voluntary cycling served as controls (C). Ten SCI (level of injury: C5-T7) and six C exercised for 30 min at comparable oxygen uptake rates (approximately 1 l/min), and [1-14C]palmitate was infused continuously to estimate FFA turnover. From femoral arteriovenous differences, blood flow, muscle biopsies, and indirect calorimetry, leg substrate balances as well as concentrations of intramuscular substrates were determined. Leg oxygen uptake was similar in the two groups during exercise. In SCI, but not in C, plasma FFA and FFA appearance rate fell during exercise, and plasma glycerol increased less than in C (P < 0.05). Fractional uptake of FFA across the working legs decreased from rest to exercise in all individuals (P < 0.05) but was always lower in SCI than in C (P < 0.05). From rest to exercise, leg FFA uptake increased less in SCI than in C subjects (14 +/- 3 to 57 +/- 20 vs. 41 +/- 13 to 170 +/- 57 micromol x min(-1) x leg(-1); P < 0.05). Muscle glycogen breakdown, leg glucose uptake, carbohydrate oxidation, and lactate release were higher (P < 0.05) in SCI than in C during exercise. Counterregulatory hormonal changes were more pronounced in SCI vs. C, whereas insulin decreased only in C. In conclusion, FFA mobilization, delivery, and fractional uptake are lower and muscle glycogen breakdown and glucose uptake are higher in SCI patients during electrically induced leg exercise compared with healthy subjects performing voluntary exercise. Apparently, blood-borne mechanisms are not sufficient to elicit a normal increase in fatty acid mobilization during exercise. Furthermore, in exercising muscle, FFA delivery enhances FFA uptake and inhibits carbohydrate metabolism, while carbohydrate metabolism inhibits FFA uptake.     

Reliability and Responsiveness of Cardiopulmonary Exercise Testing in Fatigued Persons with Multiple Sclerosis and Low to Mild Disability

Background

Peak oxygen uptake (VO₂peak) via cardiopulmonary exercise testing is considered the gold standard for testing aerobic capacity in healthy participants and people with various medical conditions. The reliability and responsiveness of cardiopulmonary exercise testing outcomes in persons with MS (PwMS) have not been extensively studied.

Objective

(1) to investigate the reliability of cardiopulmonary exercise parameters in PwMS; (2) to determine the responsiveness, in terms of the smallest detectable change (SDC), for each parameter.

Design

Two repeated measurements of cardiopulmonary exercise outcomes were obtained, with a median time interval of 16 days.

Methods

Thirty-two PwMS suffering from subjective fatigue performed cardiopulmonary exercise tests on a cycle ergometer, to voluntary exhaustion. We calculated the reliability, in terms of the intra-class correlation coefficient (ICC [2,k]; absolute agreement), and the measurement error, in terms of standard error of measurement (SEM) and SDC at individual (SDC_individual) and group level (SDC_group).

Results

The ICC for VO₂peak was 0.951, with an SEM of 0.131 L∙min⁻¹ and an SDC_individual of 0.364 L∙min⁻¹. When corrected for bodyweight, the ICC of VO₂peak was 0.933, with an SEM of 1.7 mL∙kg⁻¹∙min⁻¹ and in an SDC_individual of 4.6 mL∙kg⁻¹∙min⁻¹.

Limitations

Generalization of our study results is restricted to fatigued PwMS with a low to mild level of disability.

Conclusions

At individual level, cardiopulmonary exercise testing can be used reliably to assess physical fitness in terms of VO₂peak, but less so to determine significant changes. At group level, VO₂peak can be reliably used to determine physical fitness status and establish change over time.     

肺康复训练联合规律性有氧运动疗法对稳定期COPD患者心肺运动功能、生活质量和Th17/Treg细胞亚群失衡的影响

摘要 目的：观察肺康复训练联合规律性有氧运动疗法对稳定期慢性阻塞性肺疾病（COPD）患者心肺运动功能、生活质量和Th17/Treg细胞亚群失衡的影响。方法：选取2019年6月-2021年6月期间于我院接受治疗的80例稳定期COPD患者,根据随机数字表法分为观察组（40例,肺康复训练联合规律性有氧运动疗法）、对照组（40例,接受肺康复训练）,比较两组患者心肺运动功能、运动耐量、生活质量和Th17/Treg细胞亚群失衡相关指标。结果：两组干预3个月后最大分钟通气量（VEmax）、峰值摄氧量（PeakVO₂）升高,且观察组高于对照组（P<0.05）。两组干预3个月后无氧阈时二氧化碳通气当量（VE/CO₂ at AT）下降,且观察组低于对照组（P<0.05）。两组干预3个月后圣?乔治呼吸问卷（SGRQ）评分降低,且观察组低于对照组（P<0.05）。两组干预3个月后6 min步行试验（6MWT）距离、运动时间延长,且观察组长于对照组（P<0.05）。两组干预3个月后Treg含量升高,且观察组高于对照组（P<0.05）;两组干预3个月后Th17/Treg比值、Th17含量下降,且观察组低于对照组（P<0.05）。结论：肺康复训练联合规律性有氧运动疗法用于稳定期COPD患者,可改善其心肺运动功能,提高运动耐量,提高生活质量,同时还可调节Th17/Treg细胞亚群失衡。     

Catecholamine responses to high intensity cycle ergometer exercise: Body mass or body composition?

The purpose of this study was to compare the sympathoadrenergic and metabolic responses following 30 s of maximal high intensity cycle ergometry exercise when cradle resistive forces were derived from total-body mass (TBM) or fat-free mass (FFM). Increases in peak power output (PPO) and pedal velocity were recorded when resistive forces reflected FFM (953 +/- 114 W vs 1020 +/- 134 W; 134 +/- 8 rpm vs 141 +/- 7 rpm ; P < 0.05). No differences were observed between mean power output (MPO), fatigue index (FI%), work done (WD) or heart rate (HR) when the TBM and FFM protocols were compared. There were no differences between the TBM and FFM protocols for adrenaline (A), noradrenaline (NA) or blood lactate concentrations ([La-]B) recorded at rest, immediately post or 24 h post exercise. However, increases in blood concentrations of A and NA (P < 0.05) were recorded for both the TBM and FFM protocol immediately post exercise. Significant correlations (P < 0.05) were recorded between PPOs, immediate post- exercise NA and [La-]B for both the TBM and FFM protocols. [La-]B levels were also significantly elevated (P < 0.01) immediately post exercise for both the TBM and FFM protocols. The results from this study suggest that greater peak power outputs are obtainable with no subsequent differences in neurophysiological or metabolic stress as determined by plasma A, NA and [La-]B concentrations when resistive forces reflect FFM and not TBM during loading procedures. The findings also indicate that immediate post exercise concentrations return to resting levels 24 h post exercise.     

Influence of training status on maximal accumulated oxygen deficit during all-out cycle exercise

The influence of training status on the maximal accumulated oxygen deficit (MAOD) was used to assess the validity of the MAOD method during supramaximal all-out cycle exercise. Sprint trained (ST; n = 6), endurance trained (ET; n = 8), and active untrained controls (UT; n = 8) completed a 90 s all-out variable resistance test on a modified Monark cycle ergometer. Pretests included the determination of peak oxygen uptake ( O_2peak) and a series (5–8) of 5-min discontinuous rides at submaximal exercise intensities. The regression of steady-state oxygen uptake on power output to establish individual efficiency relationships was extrapolated to determine the theoretical oxygen cost of the supramaximal power output achieved in the 90 s all-out test. Total work output in 90 s was significantly greater in the trained groups (P<0.05), although no differences existed between ET and ST. Anaerobic capacity, as assessed by MAOD, was larger in ST compared to ET and UT. While the relative contributions of the aerobic and anaerobic energy systems were not significantly different among the groups, ET were able to achieve significantly more aerobic work than the other two groups, while ST were able to achieve significantly more anaerobic work. Peak power and peak pedalling rate were significantly higher in ST. The results suggested that MAOD determined during all-out exercise was sensitive to training status and provided a useful assessment of anaerobic capacity. In our study sprint training, compared with endurance training, appeared to enhance significantly power output and high intensity performance over brief periods (up to 60 s), yet few overall differences in performance (i.e. total work) existed during 90 s of all-out exercise.     

Pulmonary Hypertension in Patients with Idiopathic Pulmonary Fibrosis – The Predictive Value of Exercise Capacity and Gas Exchange Efficiency

Exercise capacity and survival of patients with IPF is potentially impaired by pulmonary hypertension. This study aims to investigate diagnostic and prognostic properties of gas exchange during exercise and lung function in IPF patients with or without pulmonary hypertension.In a multicentre setting, patients with IPF underwent right heart catheterization, cardiopulmonary exercise and lung function testing during their initial evaluation. Mortality follow up was evaluated.Seventy-three of 135 patients [82 males; median age of 64 (56; 72 years)] with IPF had pulmonary hypertension as assessed by right heart catheterization [median mean pulmonary arterial pressure 34 (27; 43) mmHg]. The presence of pulmonary hypertension was best predicted by gas exchange efficiency for carbon dioxide (cut off ≥152% predicted; area under the curve 0.94) and peak oxygen uptake (≤56% predicted; 0.83), followed by diffusing capacity. Resting lung volumes did not predict pulmonary hypertension. Survival was best predicted by the presence of pulmonary hypertension, followed by peak oxygen uptake [HR 0.96 (0.93; 0.98)].Pulmonary hypertension in IPF patients is best predicted by gas exchange efficiency during exercise and peak oxygen uptake. In addition to invasively measured pulmonary arterial pressure, oxygen uptake at peak exercise predicts survival in this patient population.