Medicine and Science in Sports and Exercise最新文献

Purpose: A common side effect of cancer and anticancer treatment is cancer-associated cachexia (CAC), a multifactorial syndrome characterized by the loss of bodyweight, skeletal muscle, and adipose tissue. Recommended therapeutic options are multidimensional, including nutritional, pharmacological, and exercise interventions. A novel therapeutic approach is the use of low-load resistance training combined with blood flow restriction to the trained limbs (LL-BFR). It has been shown to induce adaptations in muscle mass and strength despite a low training load in various clinical populations and might be a suitable training modality for cancer patients suffering from CAC.

Methods: A 56-year-old female patient diagnosed with stage IV gallbladder cancer, suffering from CAC, performed LL-BFR training twice weekly for 12 wk and received a guideline-based nutritional intervention. All outcome measures (maximal strength (8RM), handgrip strength, body mass, lean body mass, body cell mass, quality of life (QoL), and symptom burden) were evaluated before and directly after the training period.

Results: Adherence was moderate (67% of all training sessions completed), and no adverse events were noted. All measures of physical capacity and body composition improved between 19% to 55% and 9% to 11%, respectively. QoL decreased in 5/6 subscales, while symptom burden increased in 2/4 subscales.

Conclusions: Treatment of CAC requires a multitargeted and interdisciplinary approach. This is the first case study using LL-BFR training in an oncological patient during active therapy. Our results show that LL-BFR was feasible and, despite no positive effect on QoL and symptom burden, could induce relevant changes of muscle strength and muscle mass in a relatively short training period. Further research is necessary to confirm the results of this case study in randomized controlled trials.

Purpose: Existing literature indicates that physical fitness affects endogenous pain modulation capacity, potentially impacting populations with impaired pain modulation ability. However, current evidence remains inconsistent, and there is a lack of studies employing objective measures to examine this relationship. The objective of this study was to assess whether individual physical performance levels can predict endogenous pain modulation variables in the electroencephalogram (EEG).

Methods: The EEG-based somatosensory response following noxious mechanical stimulation was recorded as pinprick-evoked potentials during conditioned pain modulation (CPM) in 32 healthy adults. To analyze physical fitness, cardiorespiratory fitness (CRF) was measured by using spiroergometric analysis, and strength was tested using isokinetic strength testing. Bivariate linear regressions were calculated to analyze a potential relationship between physical performance parameters and CPM variables.

Results: Subjects with higher CRF exhibited a greater decrease in the event-related spectral perturbations in the CPM paradigm in the EEG and a correspondingly lower activation during a conditioning stimulus. The CRF predicted 14.0% of the variance in the activation during the conditioning stimulus (large effect) and 10.2% of the decrease in the event-related spectral perturbations in the CPM paradigm (moderate effect). No such relationship was observed between strength and EEG-based variables. When the groups were separated according to their physical fitness levels, no differences were observed between the groups during isolated mechanical stimulation.

Conclusions: The results indicate that CRF is associated with altered somatosensory responses during the CPM paradigm in our EEG-based pattern. Higher CRF appears to facilitate pain modulation processes without affecting central sensitivity to noxious mechanical stimulation, highlighting the potential benefits of higher levels of endurance exercise, but not strength levels.

Introduction/purpose: This study investigated the effect of breast size on running economy, breast displacement, total body center of mass excursion, trunk angular velocity, and exercise-induced breast pain at different running velocities.

Methods: Fifteen female recreational runners with a small breast size (volume range: 90-338 mL per breast) and 15 female recreational runners with a medium-large breast size (volume range: 351-1029 mL per breast) were matched for age and body mass index. Kinematic and oxygen consumption (V̇O 2 ) data were collected while participants completed an 8-min treadmill protocol at two incremental velocities (8 and 10 km·h -1 ).

Results: Running economy was not affected by breast volume. Multiplanar breast displacement was significantly greater for larger breast volumes, despite participants wearing a high-support sports bra. A higher breast volume was also associated with less vertical center of mass excursion at velocity of 10 km·h -1 and higher trunk lateral flexion angular velocity at foot flat.

Conclusions: Women with large breast volumes experience significantly more breast motion compared with their smaller breasted counterparts during running, despite the presence of a high-support sports bra. Although increased breast motion as a result of breast size did not translate to differences in running economy, it did alter upper body biomechanical factors known to influence running economy-total body center of mass vertical excursion and peak angular velocity of the trunk in the frontal plane. Future research should explore what effect excessive trunk motion has on the mechanics of the lower limb during running among women across the breast size spectrum, as well as how this may influence neuromuscular control and coordination between the upper and the lower limb during running.

Purpose: This study aimed to determine the relationship between changes in daily physical activity (PA) and knee health 18 months after anterior cruciate ligament reconstruction (ACLR). Knee health was defined using structural (quantitative magnetic resonance imaging) and functional (patient-reported and objectively measured knee function) constructs.

Methods: Eighteen individuals (83.3% female, 19.7 ± 5.6 yr old, BMI 23.9 ± 3.7 kg·m -2 ) completed testing. Daily steps over 1 wk and structural cartilage health, measured using a waist-worn accelerometer (Actigraph wGT3X-BT; ActiGraph Corp., Pensacola, FL) and T2 relaxation time on magnetic resonance imaging, respectively, were collected 6 and 18 months after ACLR. Eighteen months after ACLR, patient-reported and objectively measured knee health was assessed using the International Knee Documentation Committee Subjective Knee Form (IKDC) and isometric quadriceps strength, respectively. A linear regression model was used to test the relationship between the change in PA from 6 to 18 months after ACLR and the percentage change in T2 relaxation time of four cartilage regions (lateral and medial femoral and tibial cartilage) from 6 to 18 months after ACLR. A Fisher's exact test was used to assess the relationship between change in PA (increase/decrease) between 6 and 18 months after ACLR and adequate/inadequate knee function using patient-reported (IKDC) and objectively measured (quadriceps strength) knee function 18 months after ACLR.

Results: Participants averaged 7547.3 ± 2439.7 daily steps 6 months after ACLR and 7504.9 ± 3736.3 daily steps 18 months after ACLR. There was no association between change in PA and structural knee health ( P = 0.069) or knee function ( P = 0.638).

Conclusions: Average daily steps did not change from 6 to 18 months after ACLR. PA from 6 to 18 months after ACLR was not associated with knee health outcomes at 18 months.

Introduction: The influence of reduced blood volume on prolonged submaximal exercise is unclear. Using a sham-controlled design, we investigated the effect of acute phlebotomy on physiological responses to 60 min of submaximal exercise and its subsequent impact on severe-intensity exercise performance.

Methods: After baseline testing and a control trial, 17 moderately trained participants (5 female) underwent phlebotomy (PHLE) to withdraw 7% of total blood volume or a sham procedure (SHAM). Cardiorespiratory, metabolic, perceptual, and neuromuscular responses were assessed before, during, and after 60 min of submaximal exercise in the heavy domain (midway between the respiratory compensation point and the gas exchange threshold; 71% [6%] of V̇O 2max ) and in response to a subsequent severe-intensity time-to-task failure (TTF) trial.

Results: Phlebotomy significantly affected ventilation (V̇ E ; +6% [7%] vs control trial), ventilatory equivalent (+8% [8%]), heart rate (HR; +5% [4%]), O 2 pulse (-6% [5%]), and blood lactate ([La]; +25% [32%]) during submaximal exercise ( P < 0.05). Submaximal V̇O 2 , respiratory exchange ratio, perceived effort, and maximal voluntary contraction were unaffected by phlebotomy ( P > 0.05). Phlebotomy reduced TTF by 24% [23%] ( P = 0.018) without significantly reducing V̇O 2peak (-5.6% [7.5%], P = 0.09). Changes in V̇ E ( P = 0.004), HR ( P = 0.003), O 2 pulse ( P = 0.009), and [La] ( P < 0.001) between the control and experimental submaximal trials were correlated with changes in TTF (0.40 < R2 < 0.68).

Conclusions: Circulating vascular volumes impact physiological responses to submaximal exercise and influence subsequent maximal exercise performance.

Background: Exogenous ketosis, induced via ketone monoester (KE) ingestion, can attenuate blood desaturation and muscle deoxygenation during hypoxic exercise. However, its effect(s) on exercise capacity and underlying integrated physiological responses to incremental exercise to exhaustion during early acclimatization at terrestrial high altitude remain unexplored.

Methods: Healthy active adults were randomized to an intermittent exogenous ketosis (IEK; n = 16) or placebo (PLA, n = 17) group, before performing two incremental cycling tests to volitional exhaustion. The first was conducted at sea level (295 m) without prior supplementation. The second was conducted at high altitude (3375 m) after ~69 h of acclimatization, during which participants intermittently ingested KE (IEK) or placebo (PLA). During exercise, gas exchange, cardiac output, and both blood and muscle oxygenation were recorded continuously using a metabolic cart, transthoracic impedance, earlobe oximetry and near-infrared spectroscopy, respectively.

Results: Preexercise blood ketone concentrations were higher in IEK than PLA (~2.1 mM vs ~0.3 mM, P < 0.001). However, both experimental groups exhibited comparable ( P = 0.525-0.644) high altitude-induced reductions in peak power output ( P < 0.001), as well as in blood ( P < 0.001) and muscle oxygenation ( P < 0.001) during maximal exercise and submaximal power levels. Furthermore, high altitude significantly increased resting and/or exercising ventilation ( P < 0.001) and cardiac output ( P < 0.001), yet irrespective of the KE versus placebo ingestion ( P = 0.529-0.828).

Conclusions: These findings indicate that intermittent exogenous ketosis during early acclimatization does not mitigate altitude- and exercise-induced reductions in blood and muscle oxygenation. Moreover, it does not importantly modulate ventilatory and cardiac output responses, and therefore does not seem to confer ergogenic advantage during subacute high altitude exposures.

Introduction: Chronic obstructive pulmonary disease is a leading cause of mortality worldwide and a debilitating condition that leads to years of poor quality of life. Physical exercise training is an evidence-based treatment well documented to improve these outcomes as well as morbidity, dyspnea, and functional capacity. Moreover, scientific evidence from pooled analyses currently provides equivocal evidence for oxygen supplementation to overcome ventilatory limitations during exercise training, with several studies reporting no additional benefits when compared with training in room air. However, when individually analyzing the underlying studies from an exercise physiology perspective, some critical aspects arise.

Purpose: This review aims to systematically investigate and highlight the impact of patients' characteristics, exercise-induced desaturation, oxygen delivery, influence of breathing conditions during exercise testing and prescription, outcome-training specificity, exercise intensity and modality, and progressive work rate adjustments over the course of the training intervention.

Methods: The research methodology is based on a literature search of the available evidence starting from the published systematic reviews and meta-analyses, and integrating available original articles from the respective reference lists.

Results: Although evidence is still limited, supplemental oxygen might be specifically useful for certain responding patients and in specific clinical conditions, when high-intensity training is performed, thereby increasing exercise tolerance in order to improve training adaptations and thus peak exercise capacity/endurance.

Conclusions: Future well-designed clinical trials may better implement these methodological training principles in their study design and investigate if advantages from normoxic and hyperoxic exercise training can be weighed, showing how, when, and in which patients supplemental oxygen could be best used in order to reach predefined training goals in pulmonary rehabilitation.