Exercise Prescription for Postprandial Glycemic Management

The detrimental impacts of postprandial hyperglycemia on health are a critical concern, and exercise is recognized a pivotal tool in enhancing glycemic control after a meal. However, current exercise recommendations for managing postprandial glucose levels remain fairly broad and require deeper clarification. This review examines the existing literature aiming to offer a comprehensive guide for exercise prescription to optimize postprandial glycemic management. Specifically, it considers various exercise parameters (i.e., exercise timing, type, intensity, volume, pattern) for crafting exercise prescriptions. Findings predominantly indicate that moderate-intensity exercise initiated shortly after meals may substantially improve glucose response to a meal in healthy individuals and those with type 2 diabetes. Moreover, incorporating short activity breaks throughout the exercise session may provide additional benefits for reducing glucose response.

Sensorimotor integration is affected by acute whole-body vibration: a coherence study

Introduction: Several whole-body vibration (WBV) effects on performance have been related to potential changes in the neural drive, motor unit firing rate, and sensorimotor integration. In the present paper, motor unit coherence analysis was performed to detect the source of neural modulation based on the frequency domain. Methods: Thirteen men [25 ± 2.1 years; Body Mass Index (BMI) = 23.9 ± 1.3 kg m2; maximal voluntary force (MVF): 324.36 ± 41.26 N] performed sustained contractions of the Tibialis Anterior (TA) at 10%MVF before and after acute WBV. The vibrating stimulus was applied barefoot through a platform to target the TA. High-Density surface Electromyography (HDsEMG) was used to record the myoelectrical activity of TA to evaluate coherence from motor unit cumulative spike-trains (CSTs). Results: Mean coherence showed a significant decrease in the alpha and low-beta bandwidths (alpha: from 0.143 ± 0.129 to 0.132 ± 0.129, p = 0.035; low-beta: from 0.117 ± 0.039 to 0.086 ± 0.03, p = 0.0001), whereas no significant changes were found in the other ones (p > 0.05). The discharge rate (DR) and the Force Covariance (CovF%) were not significantly affected by acute WBV exposure (p > 0.05). Discussion: According to the significant effects found in alpha and low-beta bandwidths, which reflect sensorimotor integration parameters, accompanied by no differences in the DR and CovF%, the present results underlined that possible neural mechanisms at the base of the previously reported performance enhancements following acute WBV are likely based on sensorimotor integration rather than direct neural drive modulation.

Muscular Adaptations to Concurrent Resistance Training and High-Intensity Interval Training in Adults with Type 2 Diabetes: A Pilot Study

This pilot study aimed to compare the effects of eight weeks of concurrent resistance training (RT) and high-intensity interval training (HIIT) vs. RT alone on muscle performance, mass and quality in adults with type 2 diabetes (T2DM). Twelve T2DM adults were randomly allocated to the RT + HIIT (n = 5) or RT (n = 7) group. Before and after training, maximal oxygen uptake (VO2max), muscle strength and power were evaluated by calorimetry, dynamometry and one-repetition maximum (1RM) test. Quadriceps muscle volume was determined by MRI, and muscle quality was estimated. After RT, VO2max (+12%), knee muscle power (+20%), quadriceps muscle volume (+5.9%) and quality (leg extension, +65.4%; leg step-up, +223%) and 1RM at leg extension (+66.4%), leg step-up (+267%), lat pulldown (+60.9%) and chest press (+61.2%) significantly increased. The RT + HIIT group improved on VO2max (+27%), muscle volume (+6%), muscle power (+9%) and 1RM at lat pulldown (+47%). No other differences were detected. Among groups, changes in muscle quality at leg step-up and leg extension and VO2max were significantly different. The combination of RT and HIIT effectively improves muscle function and size and increases cardiorespiratory fitness in adults with T2DM. However, HIIT combined with RT may interfere with the development of muscle quality.

Sustained increase in physical fitness independently predicts improvements in cardiometabolic risk profile in type 2 diabetes

AIMS

To investigate the relationship between changes in physical fitness and cardiovascular risk factors and scores in patients with type 2 diabetes receiving either a behavioural counselling intervention to increase moderate-to-vigorous-intensity physical activity (MVPA) and decrease sedentary-time (SED-time) or standard care.

MATERIALS AND METHODS

This is a pre-specified ancillary analysis of the Italian Diabetes and Exercise Study_2, a 3-year randomized clinical trial in which 300 physically inactive and sedentary patients were randomized 1:1 to receive either a one-month theoretical and practical counselling each year or standard care. Mean changes from baseline throughout the 3-year period in MVPA, SED-time, cardiorespiratory fitness (VO2max ), muscle strength, flexibility, cardiovascular risk factors and scores were calculated for study completers (n = 267) and considered irrespective of study arm.

RESULTS

Haemoglobin (Hb) A1c and coronary heart disease (CHD) risk scores decreased with quartiles of VO2max and lower body muscle strength changes. Multivariable linear regression analysis showed that increases in VO2max independently predicted decreases in HbA1c , blood glucose, diastolic blood pressure (BP), CHD and total stroke 10-year risk and increases in HDL cholesterol, whereas increases in lower body muscle strength independently predicted decreases in body mass index (BMI), waist circumference, triglycerides, systolic BP, CHD and fatal stroke 10-year risk. These associations remained after including changes in BMI, waist circumference, fat mass and fat-free mass, or MVPA and SED-time as covariates.

CONCLUSIONS

Improvement in physical fitness predicts favourable changes in cardiometabolic risk profile, independent of changes not only in (central) adiposity or body composition but also in MVPA and SED-time.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT01600937; URL https://clinicaltrials.gov/ct2/show/NCT01600937.

Ventilation and perceived exertion are sensitive to changes in exercise tolerance: arm+leg cycling vs. leg cycling

Purpose: Growing evidence suggests that respiratory frequency (f R) is a marker of physical effort and a variable sensitive to changes in exercise tolerance. The comparison between arm+leg cycling (Arm+leg) and leg cycling (Leg) has the potential to further test this notion because a greater exercise tolerance is expected in the Arm+leg modality. We systematically compared Arm+leg vs. Leg using different performance tests. Methods: Twelve males underwent six performance tests in separate, randomized visits. Three tests were performed in each of the two exercise modalities, i.e. an incremental test and two time-to-exhaustion (TTE) tests performed at 90% or 75% of the peak power output reached in the Leg incremental test (PPOLeg). Exercise tolerance, perceived exertion, and cardiorespiratory variables were recorded during all the tests. Results: A greater exercise tolerance (p < 0.001) was found for Arm+leg in the incremental test (337 ± 32 W vs. 292 ± 28 W), in the TTE test at 90% of PPOLeg (638 ± 154 s vs. 307 ± 67 s), and in the TTE test at 75% of PPOLeg (1,675 ± 525 s vs. 880 ± 363 s). Unlike V ˙ O2 and heart rate, both f R and minute ventilation were lower (p < 0.003) at isotime in all the Arm+leg tests vs. Leg tests. Furthermore, a lower perceived exertion was observed in the Arm+leg tests, especially during the TTE tests (p < 0.001). Conclusion: Minute ventilation, f R and perceived exertion are sensitive to the improvements in exercise tolerance observed when comparing Arm+leg vs. Leg, unlike V ˙ O2 and heart rate.

Dropout and compliance to physical exercise in menopausal osteopenic women: the European "happy bones" project

Introduction

Decline in muscle mass and bone density seem to be two of the most disabling side effects of menopause that negatively affect women's quality of life. Promoting physical activity protocols in the workplace can represent a focal point in the prevention and management of several diseases. The study aims to evaluate the compliance and drop-out of menopausal osteopenic women engaged in combined training performed inside and outside the workplace. Strength and balance were analyzed to evaluate the effect of this protocol on osteoporosis prevention and the risk of falling.

Methods

73 menopausal women were enrolled in 5 European countries. They performed 72 lessons of a combined training proposed in the working place (IW) or sport center (SC).

Results

Out of the total 39 women enrolled in the IW, 12.8% had to leave the program, while out of the 34 women enrolled in SC, 41.2% did not complete the training. According to the compliance results, 47% of women that completed the trained IW and 85% in the SC recorded high compliance (p = 0.019). Moreover, the strength of the lower limbs (p < 0.001) and static balance (p = 0.001) significantly improved in the whole group.

Discussion

In conclusion, proposing well-structured training in the workplace for menopausal women seems to reduce drop-out. Strength and balance results suggest its positive impact on bone health and risk of falls, despite where it is performed.

Respiratory Rate Estimation during Walking and Running Using Breathing Sounds Recorded with a Microphone

Emerging evidence suggests that respiratory frequency (f_R) is a valid marker of physical effort. This has stimulated interest in developing devices that allow athletes and exercise practitioners to monitor this vital sign. The numerous technical challenges posed by breathing monitoring in sporting scenarios (e.g., motion artifacts) require careful consideration of the variety of sensors potentially suitable for this purpose. Despite being less prone to motion artifacts than other sensors (e.g., strain sensors), microphone sensors have received limited attention so far. This paper proposes the use of a microphone embedded in a facemask for estimating f_R from breath sounds during walking and running. f_R was estimated in the time domain as the time elapsed between consecutive exhalation events retrieved from breathing sounds every 30 s. Data were collected from ten healthy subjects (both males and females) at rest and during walking (at 3 km/h and 6 km/h) and running (at 9 km/h and 12 km/h) activities. The reference respiratory signal was recorded with an orifice flowmeter. The mean absolute error (MAE), the mean of differences (MOD), and the limits of agreements (LOAs) were computed separately for each condition. Relatively good agreement was found between the proposed system and the reference system, with MAE and MOD values increasing with the increase in exercise intensity and ambient noise up to a maximum of 3.8 bpm (breaths per minute) and -2.0 bpm, respectively, during running at 12 km/h. When considering all the conditions together, we found an MAE of 1.7 bpm and an MOD ± LOAs of -0.24 ± 5.07 bpm. These findings suggest that microphone sensors can be considered among the suitable options for estimating f_R during exercise.

Design and Testing of a Smart Facemask for Respiratory Monitoring during Cycling Exercise

Given the importance of respiratory frequency (f_R) as a valid marker of physical effort, there is a growing interest in developing wearable devices measuring f_R in applied exercise settings. Biosensors measuring chest wall movements are attracting attention as they can be integrated into textiles, but their susceptibility to motion artefacts may limit their use in some sporting activities. Hence, there is a need to exploit sensors with signals minimally affected by motion artefacts. We present the design and testing of a smart facemask embedding a temperature biosensor for f_R monitoring during cycling exercise. After laboratory bench tests, the proposed solution was tested on cyclists during a ramp incremental frequency test (RIFT) and high-intensity interval training (HIIT), both indoors and outdoors. A reference flowmeter was used to validate the f_R extracted from the temperature respiratory signal. The smart facemask showed good performance, both at a breath-by-breath level (MAPE = 2.56% and 1.64% during RIFT and HIIT, respectively) and on 30 s average f_R values (MAPE = 0.37% and 0.23% during RIFT and HIIT, respectively). Both accuracy and precision (MOD ± LOAs) were generally superior to those of other devices validated during exercise. These findings have important implications for exercise testing and management in different populations.

Differential control of respiratory frequency and tidal volume during exercise

The lack of a testable model explaining how ventilation is regulated in different exercise conditions has been repeatedly acknowledged in the field of exercise physiology. Yet, this issue contrasts with the abundance of insightful findings produced over the last century and calls for the adoption of new integrative perspectives. In this review, we provide a methodological approach supporting the importance of producing a set of evidence by evaluating different studies together-especially those conducted in 'real' exercise conditions-instead of single studies separately. We show how the collective assessment of findings from three domains and three levels of observation support the development of a simple model of ventilatory control which proves to be effective in different exercise protocols, populations and experimental interventions. The main feature of the model is the differential control of respiratory frequency (f_R) and tidal volume (V_T); f_R is primarily modulated by central command (especially during high-intensity exercise) and muscle afferent feedback (especially during moderate exercise) whereas V_T by metabolic inputs. Furthermore, V_T appears to be fine-tuned based on f_R levels to match alveolar ventilation with metabolic requirements in different intensity domains, and even at a breath-by-breath level. This model reconciles the classical neuro-humoral theory with apparently contrasting findings by leveraging on the emerging control properties of the behavioural (i.e. f_R) and metabolic (i.e. V_T) components of minute ventilation. The integrative approach presented is expected to help in the design and interpretation of future studies on the control of f_R and V_T during exercise.

The acute effects of whole-body vibration on motor unit recruitment and discharge properties

Introduction: several studies have reported improved neuromuscular parameters in response to whole-body vibration (WBV). This is likely achieved by modulation of the central nervous system (CNS). Reduced recruitment threshold (RT), which is the % of Maximal Voluntary Force (%MVF) at which a given Motor Unit (MU) is recruited, may be responsible for the force/power improvements observed in several studies. Methods: 14 men (25 ± 2.3 years; BMI = 23.3 ± 1.5 kg m² MVF: 319.82 ± 45.74 N) performed trapezoidal isometric contractions of the tibialis anterior (TA) at 35-50-70 %MVF before and after three conditions: WBV, STAND (standing posture), and CNT (no intervention). The vibration was applied through a platform for targeting the TA. High-density surface electromyography (HDsEMG) recordings and analysis were used to detect changes in the RT and Discharge Rate (DR) of the MUs. Results: Mean motor unit recruitment threshold (MURT) reached 32.04 ± 3.28 %MVF before and 31.2 ± 3.72 %MVF after WBV, with no significant differences between conditions (p > 0.05). Additionally, no significant changes were found in the mean motor unit discharge rate (before WBV: 21.11 ± 2.94 pps; after WBV: 21.19 ± 2.17 pps). Discussion: The present study showed no significant changes in motor unit properties at the base of neuromuscular changes documented in previous studies. Further investigations are needed to understand motor unit responses to different vibration protocols and the chronic effect of vibration exposure on motor control strategies.

Walking Attenuates Postprandial Glycemic Response: What Else Can We Do without Leaving Home or the Office?

We evaluated the effects of different exercise types suitable for a home/work setting on the postprandial glucose response. Twenty-three healthy, active, young individuals performed one of two studies (12 in Study 1 and 11 in Study 2), with four randomized protocols each. After a meal high in carbohydrate content (1 g of carbohydrate per kg of body weight), in Study 1, participants performed 30 min of either walking (WALK), bench stepping exercise (STEP) or isometric wall squat (SQUAT); in Study 2, participants performed 30 min of either walking (WALK), neuromuscular electrical stimulation alone (P_NMES) or superimposed on voluntary muscle contraction (VC_NMES). In both studies, participants performed a prolonged sitting condition (CON) that was compared to the exercise sessions. In Study 1, WALK and STEP significantly reduced the glucose peak compared to CON (p < 0.011). In Study 2, the peak was significantly reduced in WALK compared to CON, P_NMES and VC_NMES (p < 0.011) and in VC_NMES compared to CON and P_NMES (p < 0.011). A significant reduction of 3 h glucose iAUC was found for WALK and VC_NMES compared to CON and P_NMES (p < 0.033). In conclusion, WALK is the most effective strategy for improving the postprandial glycemic response. However, STEP and VC_NMES can also be used for reducing postprandial glycemia.

Sustained decreases in sedentary time and increases in physical activity are associated with preservation of estimated β-cell function in individuals with type 2 diabetes

AIMS

In the Italian Diabetes and Exercise Study_2, a counselling intervention produced modest but sustained increments in moderate-to vigorous-intensity physical activity (MVPA), with reallocation of sedentary-time (SED-time) to light-intensity physical activity (LPA). This post hoc analysis evaluated the impact of intervention on estimated β-cell function and insulin sensitivity.

METHODS

Patients with type 2 diabetes were randomized to one-month counselling once-a-year or standard care for 3 years. The HOmeostatic Model Assessment-2 (HOMA-2) method was used for estimating indices of β-cell function (HOMA-B%), insulin sensitivity (HOMA-S%), and insulin resistance (HOMA-IR); the disposition index (DI) was estimated as HOMA-β%/HOMA-IR; MVPA, LPA, and SED-time were objectively measured by accelerometer.

RESULTS

HOMA-B% and DI decreased in control group, whereas HOMA-B% remained stable and DI increased in intervention group. Between-group differences were significant for almost all insulin secretion and sensitivity indices. Changes in HOMA-B% and DI correlated with SED-time, MVPA and LPA. Changes in HOMA-B%, DI, and all indices were independently predicted by changes in SED-time (or LPA), MVPA, and BMI (or waist circumference), respectively.

CONCLUSIONS

In individuals with type 2 diabetes, increasing MVPA, even without achieving the recommended target, is effective in maintaining estimated β-cell function if sufficient amounts of SED-time are reallocated to LPA.

Extreme duration exercise affects old and younger men differently

Aim & Methods

Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days.

Results

Over the 15‐day exercise intervention, participants lost 2–3 kg fat mass with no significant change in body weight. V̇O₂max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both groups, and plasma glucose increased in the younger group. In the older cohort, plasma LDL‐cholesterol and plasma triglyceride decreased. In skeletal muscle, fat transporters CD36 and FABPm remained unchanged. The glucose handling proteins GLUT4 and SNAP23 increased in both groups. Mitochondrial ROS production decreased in both groups, and ADP sensitivity increased in skeletal muscle in the older but not in the younger cohort.

Conclusion

In summary, these data suggest that older but not younger individuals experience a negative adaptive response affecting cardiovascular function in response to extreme endurance exercise, while a positive response to the same exercise intervention is observed in peripheral tissues in younger and older men. The results also suggest that the adaptive thresholds differ in younger and old men, and this difference primarily affects central cardiovascular functions in older men after extreme endurance exercise.

The Effects of Postprandial Walking on the Glucose Response after Meals with Different Characteristics

We evaluated the effect of postprandial walking on the post-meal glycemic response after meals with different characteristics. Twenty-one healthy young volunteers participated in one of two randomized repeated measures studies. Study 1 (10 participants) assessed the effects of 30 min of brisk walking after meals with different carbohydrate (CHO) content (0.75 or 1.5 g of CHO per kg/body weight). Study 2 (11 participants) evaluated the effects of 30 min of brisk walking after consuming a mixed meal or a CHO drink matched for absolute CHO content (75 g). Postprandial brisk walking substantially reduced (p < 0.009) the glucose peak in both studies, with no significant differences across conditions. When evaluating the glycemic response throughout the two hours post-meal, postprandial walking was more effective after consuming a lower CHO content (Study 1), and similarly effective after a mixed meal or a CHO drink (Study 2), although higher glucose values were observed when consuming the CHO drink. Our findings show that a 30 min postprandial brisk walking session improves the glycemic response after meals with different CHO content and macronutrient composition, with implications for postprandial exercise prescription in daily life scenarios.

Relationships of Changes in Physical Activity and Sedentary Behavior With Changes in Physical Fitness and Cardiometabolic Risk Profile in Individuals With Type 2 Diabetes: The Italian Diabetes and Exercise Study 2 (IDES_2)

OBJECTIVE

In the Italian Diabetes and Exercise Study_2 (IDES_2), behavioral counseling promoted a sustained increase in physical activity (PA) volume (+3.3 MET h ⋅ week-1), moderate- to vigorous-intensity PA (MVPA) (+6.4 min ⋅ day-1), and light-intensity PA (LPA) (+0.8 h ⋅ day-1) and decrease in sedentary time (SED-time) (-0.8 h ⋅ day-1). Here, we investigated the relationships of changes in PA/SED-time with changes in physical fitness and cardiometabolic risk profile in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In this 3-year randomized clinical trial, 300 physically inactive and sedentary patients were randomized 1:1 to receive 1-month theoretical and practical counseling once a year or standard care. Changes in physical fitness and cardiovascular risk factors/scores according to quartiles of accelerometer-measured changes in PA/SED-time were assessed, together with univariate and multivariable associations between these parameters, in the whole cohort and by study arm.

RESULTS

Physical fitness increased and HbA1c and coronary heart disease 10-year risk scores decreased with quartiles of MVPA and SED-time change. In quartile IV of MVPA increase and SED-time decrease, cardiorespiratory fitness increased by 5.23 and 4.49 mL ⋅ min-1 ⋅ kg-1 and HbA1c decreased by 0.73 and 0.85%, respectively. Univariate correlations confirmed these relationships, and mean changes in both MPVA and SED-time predicted changes in physical fitness and cardiovascular risk factors/scores independently of one another and of other confounders. Similar findings were observed with LPA and PA volume and in each group separately.

CONCLUSIONS

Even modest increments in MVPA may have a clinically meaningful impact, and reallocating SED-time to LPA may also contribute to improved outcomes, possibly by increasing total energy expenditure.

Exercise as a drug for glucose management and prevention in type 2 diabetes mellitus

Physical inactivity and sedentary behavior are risk factors for type 2 diabetes mellitus (T2DM). Therefore, physical exercise (PE) together with medical treatment might be considered as a key strategy to counteract T2DM. Glycemic control is a central objective in the prevention and management of T2DM, and PE might be able to substantially affect the processes that determine it. Just like a drug, exercise can be dosed based on the characteristics of the individual to increase its benefits and reduce side effects. In this brief review, the mechanisms underlying the effects of PE on glucose metabolism in muscle are illustrated, and the effects of modulation of the parameters characterizing this atypical "drug" on glucose homeostasis are described.

Effects of exercise before and/or after a mixed lunch on postprandial metabolic responses in healthy male individuals

PURPOSE

Exercise plays an important role in preventing and treating postprandial dysmetabolism. We investigated the postprandial metabolic responses to a standard lunch when a session of aerobic exercise is performed in the early postprandial phase or divided between the pre- and postprandial period.

METHODS

Nine healthy volunteers consumed a standardised mixed lunch and rested for the following 3 h (Con) or performed 40 min of cycling at 65% V̇O₂max after lunch (CPPEx), or two 20-min sessions, one before (SplitEx1) and the other after lunch (SplitEx2), at the same intensity.

RESULTS

At 1-h post-lunch, a significant reduction (P < 0.001) in glycaemia was observed for CPPEx (- 25 ± 10%) and SplitEx (- 34 ± 7%) compared to Con. Yet, a post-exercise rebound lessened the exercise effect on the glycaemic area under the curve (AUC) at 2 and 3 h. At 1 h, a significant reduction (P < 0.009) in plasma insulin (SplitEx - 53 ± 31%; CCPEx - 48 ± 20%) and C-peptide (SplitEx - 57 ± 20%; CCPEx - 47 ± 24%) was observed compared to Con. Glucose-dependent insulinotropic polypeptide (GIP) increased after the meal, without differences between conditions. Compared with SplitEx1, cortisol response was attenuated during SplitEx2 and CPPEx. At 3 hours, triglyceride AUC was significantly higher (P = 0.039) in SplitEx compared to Con (+ 19 ± 8%).

CONCLUSION

Forty minutes of postprandial exercise or 20 min of pre- and postprandial exercise are both effective at attenuating the glycaemic and insulinaemic response to a mixed lunch, while a higher lipaemia was found in the pre- and postprandrial exercise condition.

Dancing With Health: Quality of Life and Physical Improvements From an EU Collaborative Dance Programme With Women Following Breast Cancer Treatment

Background: Women's health has received renewed attention in the last few years including health rehabilitation options for women affected by breast cancer. Dancing has often been regarded as one attractive option for supporting women's well-being and health, but research with women recovering from breast cancer is still in its infancy. Dancing with Health is multi-site pilot study that aimed to evaluate a dance programme for women in recovery from breast cancer across five European countries.

Methods: A standardized 32 h dance protocol introduced a range of Latin American dances presented within a sports and exercise framework with influences from dance movement therapy. Fifty-four women (M age 53.51; SD 7.99) participated in the study who had a breast cancer diagnosis <3 years, chemotherapy >6 weeks, no indication of metastasis, or scheduled surgery/chemotherapy/radiation treatment for the duration of the intervention. Primary outcome data was collected for anthropometric and fitness measures next to cancer-related quality of life. T-tests and Wilcoxon signed ranked tests were used to establish differences pre and post intervention. Cohen's d was also calculated to determine the effect size of the intervention.

Results: Statistically significant changes were found for: (i) weight, right and left forearm circumference and hip; (ii) 6 min walking, right and left handgrip, sit-to-stand and sit-and-reach; (iii) the EORTC-QLQ C30 summary score as well as the subscales of emotional and social functioning and symptoms. In all cases the direction of change was positive, while Cohen's d calculated showed that the effect of the intervention for these parameters ranged from intermediate to large.

Conclusion: Changes on the above anthropometric, fitness and quality of life measures suggest that the intervention was of value to the participating women recovering from breast cancer. Results also advocate collaborative efforts across countries to further research.

Quercetin Modulates IGF-I and IGF-II Levels After Eccentric Exercise-Induced Muscle-Damage: A Placebo-Controlled Study

BACKGROUND

Prolonged or unaccustomed eccentric exercise may cause muscle damage and depending from its extent, this event negatively affects physical performance.

OBJECTIVES

The aim of the present investigation was to evaluate, in humans, the effect of the flavonoid quercetin on circulating levels of the anabolic insulin-like growth factor 1 (IGF-I) and insulin-like growth factor 2 (IGF-II), produced during the recovery period after an eccentric-induced muscle damage (EIMD).

METHODS

A randomized, double-blind, crossover study has been performed; twelve young men ingested quercetin (1 g/day) or placebo for 14 days and then underwent an eccentric-induced muscle damaging protocol. Blood samples were collected, and cell damage markers [creatine kinase (CK), lactate dehydrogenase (LDH) and myoglobin (Mb)], the inflammatory responsive interleukin 6 (IL-6), IGF-I and IGF-II levels were evaluated before the exercise and at different recovery times from 24 hours to 7 days after EIMD.

RESULTS

We found that, in placebo treatment the increase in IGF-I (72 h) preceded IGF-II increase (7 d). After Q supplementation there was a more marked increase in IGF-I levels and notably, the IGF-II peak was found earlier, compared to placebo, at the same time of IGF-I (72 h). Quercetin significantly reduced plasma markers of cell damage [CK (p<0.005), LDH (p<0.001) and Mb (p<0.05)] and the interleukin 6 level [IL-6 (p<0.05)] during recovery period following EIMD compared to placebo.

CONCLUSIONS

Our data are encouraging about the use of quercetin as dietary supplementation strategy to adopt in order to mitigate and promote a faster recovery after eccentric exercise as suggested by the increase in plasma levels of the anabolic factors IGF-I and IGF-II.

The Importance of Respiratory Rate Monitoring: From Healthcare to Sport and Exercise

Respiratory rate is a fundamental vital sign that is sensitive to different pathological conditions (e.g., adverse cardiac events, pneumonia, and clinical deterioration) and stressors, including emotional stress, cognitive load, heat, cold, physical effort, and exercise-induced fatigue. The sensitivity of respiratory rate to these conditions is superior compared to that of most of the other vital signs, and the abundance of suitable technological solutions measuring respiratory rate has important implications for healthcare, occupational settings, and sport. However, respiratory rate is still too often not routinely monitored in these fields of use. This review presents a multidisciplinary approach to respiratory monitoring, with the aim to improve the development and efficacy of respiratory monitoring services. We have identified thirteen monitoring goals where the use of the respiratory rate is invaluable, and for each of them we have described suitable sensors and techniques to monitor respiratory rate in specific measurement scenarios. We have also provided a physiological rationale corroborating the importance of respiratory rate monitoring and an original multidisciplinary framework for the development of respiratory monitoring services. This review is expected to advance the field of respiratory monitoring and favor synergies between different disciplines to accomplish this goal.

Quercetin Supplementation Improves Neuromuscular Function Recovery from Muscle Damage

This study was aimed at investigating whether quercetin (Q) may improve the recovery of neuromuscular function and biochemical parameters in the 7 days following an eccentric exercise-induced muscle damage (EEIMD). Sixteen men (25.9 ± 3.3 y) ingested Q (1000 mg/day) or placebo (PLA) for 14 days following a double-blind crossover study design. A neuromuscular (NM) test was performed pre–post, 24 h, 48 h, 72 h, 96 h and 7 days after an intense eccentric exercise. The force–velocity relationship of the elbow flexor muscles and their maximal voluntary isometric contraction (MVIC) were recorded simultaneously to the electromyographic signals (EMG). Pain, joint angle, arm circumference, plasma creatine kinase (CK) and lactate-dehydrogenase (LDH) were also assessed. The results showed that Q supplementation significantly attenuated the strength loss compared to PLA. During the recovery, force–velocity relationship and mean fibers conduction velocity (MFCV) persisted significantly less when participants consumed PLA rather than Q, especially at the highest angular velocities (p < 0.02). A greater increase in biomarkers of damage was also evident in PLA with respect to Q. Q supplementation for 14 days seems able to ameliorate the recovery of eccentric exercise-induced weakness, neuromuscular function impairment and biochemical parameters increase probably due to its strong anti-inflammatory and antioxidant action.

Ocular surface involvement in patients with neurofibromatosis type 1 syndrome

PURPOSE

The aim of this study is to evaluate ocular surface morphological and functional changes in patients with neurofibromatosis type 1 (NF1).

METHODS

Twenty-eight patients with NF1 and 14 healthy subjects were included in this study. All participants underwent a medical history collection, a complete ophthalmological examination including slit lamp exam and assessment of best-corrected visual acuity (BCVA), corneal sensitivity, and lacrimal function (Schirmer test and fluorescein tear break-up time test). Corneal nerves' morphology and endothelial cells density were evaluated by in vivo corneal confocal microscopy (IVCM). Tear and conjunctiva epithelium samples were collected to evaluate nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) tear levels and conjunctival expression of their receptors TrkA and p75NTR.

RESULTS

Patients with NF1 showed a significant decrease of FTBUT when compared with healthy subjects (p < 0.001). Corneal sensitivity was ≤ 50 mm in 46% of NF1 patients. IVCM showed a significant increase of corneal nerve branching and of corneal endothelial cells density. No significant difference was observed between the two groups on NGF and BDNF tear levels and conjunctival expression of their receptors.

CONCLUSION

This study demonstrated the presence of ocular surface changes in NF-1 patients including decrease of tear stability and of corneal sensitivity. Patients with NF1 also showed changes of corneal endothelial cells' density.

Muscle fatigability in patients with type 2 diabetes: relation with long-term complications

AIMS

It is unclear whether long-term complications play a role in muscle fatigue characteristic of patients with type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the association between muscle fatigability and microvascular and macrovascular complications in patients with T2DM.

METHODS

One-hundred forty-six patients with T2DM (80 males, 66 females, aged 66.9 ± 7.9 years) were recruited. Maximal voluntary contraction (MCV) and endurance time (ET, 50% of the MVC) were assessed at the knee extensor muscles with an isometric dynamometer. Univariate and multivariate correlations of ET values with diabetic complications, a wide range of surrogate measures of these sequelae, and cardiovascular risk factors were examined.

RESULTS

A higher muscle fatigability was detected in patients with diabetic peripheral neuropathy (DPN, ET: -32.4%), cardiovascular disease (CVD, ET: -32.1%), retinopathy (ET: -35.8%), and nephropathy (ET: -30.4%). At univariate analysis, muscle fatigability was associated with age, physical activity level, diabetes duration, HbA_1c , systolic blood pressure, albuminuria, eGFR, and several parameters of nervous and vascular function. Multivariate analysis showed that, after adjusting for covariates, ET was independently associated with sensory nerve conduction velocity, vibration perception threshold at malleolus, and ankle-brachial index. In addition, ET values were independently associated with the presence of DPN, CVD, and retinopathy.

CONCLUSIONS

In T2DM, muscle fatigability is associated with presence of DPN, CVD, and retinopathy. Such defect appears to be mediated predominantly by sensory nerve and peripheral vascular dysfunction.

Respiratory Frequency as a Marker of Physical Effort During High-Intensity Interval Training in Soccer Players

PURPOSE

Variables currently used in soccer training monitoring fail to represent the physiological demand of the player during movements like accelerations, decelerations, and directional changes performed at high intensity. We tested the hypothesis that respiratory frequency (fR) is a marker of physical effort during soccer-related high-intensity exercise.

METHODS

A total of 12 male soccer players performed a preliminary intermittent incremental test and 2 shuttle-run high-intensity interval training (HIIT) protocols, in separate visits. The 2 HIIT protocols consisted of 12 repetitions over 9 minutes and differed in the work-to-recovery ratio (15:30 vs 30:15 s). Work rate was self-paced by participants to achieve the longest possible total distance in each HIIT protocol.

RESULTS

Work-phase average metabolic power was higher (P < .001) in the 15:30-second protocol (31.7 [3.0] W·kg-1) compared with the 30:15-second protocol (22.8 [2.0] W·kg-1). Unlike heart rate and oxygen uptake, fR showed a fast response to the work-recovery alternation during both HIIT protocols, resembling changes in metabolic power even at supramaximal intensities. Large correlations (P < .001) were observed between fR and rating of perceived exertion during both 15:30-second (r = .87) and 30:15-second protocols (r = .85).

CONCLUSIONS

Our findings suggest that fR is a good marker of physical effort during shuttle-run HIIT in soccer players. These findings have implications for monitoring training in soccer and other team sports.

Study to Weigh the Effect of Exercise Training on BONE quality and strength (SWEET BONE) in type 2 diabetes: study protocol for a randomised clinical trial

INTRODUCTION

Type 2 diabetes (T2D) is associated with an increased fracture risk despite normal-to-increased bone mineral density, suggesting reduced bone quality. Exercise may be effective in reducing fracture risk by ameliorating muscle dysfunction and reducing risk of fall, though it is unclear whether it can improve bone quality.

METHODS AND ANALYSIS

The 'Study to Weigh the Effect of Exercise Training on BONE quality and strength (SWEET BONE) in T2D' is an open-label, assessor-blinded, randomised clinical trial comparing an exercise training programme of 2-year duration, specifically designed for improving bone quality and strength, with standard care in T2D individuals. Two hundred T2D patients aged 65-75 years will be randomised 1:1 to supervised exercise training or standard care, stratified by gender, age ≤ or >70 years and non-insulin or insulin treatment. The intervention consists of two weekly supervised sessions, each starting with 5 min of warm-up, followed by 20 min of aerobic training, 30 min of resistance training and 20 min of core stability, balance and flexibility training. Participants will wear weighted vests during aerobic and resistance training. The primary endpoint is baseline to end-of-study change in trabecular bone score, a parameter of bone quality consistently shown to be reduced in T2D. Secondary endpoints include changes in other potential measures of bone quality, as assessed by quantitative ultrasound and peripheral quantitative CT; bone mass; markers of bone turnover; muscle strength, mass and power; balance and gait. Falls and asymptomatic and symptomatic fractures will be evaluated over 7 years, including a 5-year post-trial follow-up. The superiority of the intervention will be assessed by comparing between-groups baseline to end-of-study changes.

ETHICS AND DISSEMINATION

This study was approved by the institutional ethics committee. Written informed consent will be obtained from all participants. The study results will be submitted for peer-reviewed publication.

TRIAL REGISTRATION NUMBER

NCT02421393; Pre-results.

Effect of a Behavioral Intervention Strategy on Sustained Change in Physical Activity and Sedentary Behavior in Patients With Type 2 Diabetes: The IDES_2 Randomized Clinical Trial

IMPORTANCE

There is no definitive evidence that changes in physical activity/sedentary behavior can be maintained long term in individuals with type 2 diabetes.

OBJECTIVE

To investigate whether a behavioral intervention strategy can produce a sustained increase in physical activity and reduction in sedentary time among individuals with type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

The Italian Diabetes and Exercise Study 2 was an open-label, assessor-blinded, randomized clinical superiority trial, with recruitment from October 2012 to February 2014 and follow-up until February 2017. In 3 outpatient diabetes clinics in Rome, 300 physically inactive and sedentary patients with type 2 diabetes were randomized 1:1 (stratified by center, age, and diabetes treatment) to receive a behavioral intervention or standard care for 3 years.

INTERVENTIONS

All participants received usual care targeted to meet American Diabetes Association guideline recommendations. Participants in the behavioral intervention group (n = 150) received 1 individual theoretical counseling session and 8 individual biweekly theoretical and practical counseling sessions each year. Participants in the standard care group (n = 150) received only general physician recommendations.

MAIN OUTCOMES AND MEASURES

Co-primary end points were sustained change in physical activity volume, time spent in light-intensity and moderate- to vigorous-intensity physical activity, and sedentary time, measured by an accelerometer.

RESULTS

Of the 300 randomized participants (mean [SD] age, 61.6 [8.5] years; 116 women [38.7%]), 267 completed the study (133 in the behavioral intervention group and 134 in the standard care group). Median follow-up was 3.0 years. Participants in the behavioral intervention and standard care groups accumulated, respectively, 13.8 vs 10.5 metabolic equivalent-h/wk of physical activity volume (difference, 3.3 [95% CI, 2.2-4.4]; P < .001), 18.9 vs 12.5 min/dof moderate- to vigorous-intensity physical activity (difference, 6.4 [95% CI, 5.0-7.8]; P < .001), 4.6 vs 3.8 h/d of light-intensity physical activity (difference, 0.8 [95% CI, 0.5-1.1]; P < .001), and 10.9 vs 11.7 h/d of sedentary time (difference, -0.8 [95% CI, -1.0 to -0.5]; P < .001). Significant between-group differences were maintained throughout the study, but the between-group difference in moderate- to vigorous-intensity physical activity decreased during the third year from 6.5 to 3.6 min/d. There were 41 adverse events in the behavioral intervention group and 59 in the standard care group outside of the sessions; participants in the behavioral intervention group experienced 30 adverse events during the sessions (most commonly musculoskeletal injury/discomfort and mild hypoglycemia).

CONCLUSIONS AND RELEVANCE

Among patients with type 2 diabetes at 3 diabetes clinics in Rome who were followed up for 3 years, a behavioral intervention strategy compared with standard care resulted in a sustained increase in physical activity and decrease in sedentary time. Further research is needed to assess the generalizability of these findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01600937.

Contact-Based Methods for Measuring Respiratory Rate

There is an ever-growing demand for measuring respiratory variables during a variety of applications, including monitoring in clinical and occupational settings, and during sporting activities and exercise. Special attention is devoted to the monitoring of respiratory rate because it is a vital sign, which responds to a variety of stressors. There are different methods for measuring respiratory rate, which can be classed as contact-based or contactless. The present paper provides an overview of the currently available contact-based methods for measuring respiratory rate. For these methods, the sensing element (or part of the instrument containing it) is attached to the subject's body. Methods based upon the recording of respiratory airflow, sounds, air temperature, air humidity, air components, chest wall movements, and modulation of the cardiac activity are presented. Working principles, metrological characteristics, and applications in the respiratory monitoring field are presented to explore potential development and applicability for each method.

The Effects of Quercetin Supplementation on Eccentric Exercise-Induced Muscle Damage

The aim of the present investigation was to test the hypothesis that quercetin (Q) may prevent the strength loss and neuromuscular impairment associated with eccentric exercise-induced muscle damage (EEIMD). Twelve young men (26.1 ± 3.1 years) ingested either Q (1000 mg/day) or placebo (PLA) for 14 days using a randomized, double-blind, crossover study design. Participants completed a comprehensive neuromuscular (NM) evaluation before, during and after an eccentric protocol able to induce a severe muscle damage (10 sets of 10 maximal lengthening contractions). The NM evaluation comprised maximal voluntary isometric contraction (MVIC) and force–velocity relationship assessments with simultaneous recording of electromyographic signals (EMG) from the elbow flexor muscles. Soreness, resting arm angle, arm circumference, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) were also assessed. Q supplementation significantly increased the isometric strength recorded during MVIC compared to baseline (+4.7%, p < 0.05). Moreover, the torque and muscle fiber conduction velocity (MFCV) decay recorded during the eccentric exercise was significant lower in Q compared to PLA. Immediately after the EEIMD, isometric strength, the force–velocity relationship and MFCV were significantly lower when participants were given PLA rather than Q. Fourteen days of Q supplementation seems able to attenuate the severity of muscle weakness caused by eccentric-induced myofibrillar disruption and sarcolemmal action potential propagation impairment.

Carbohydrate Supplementation Does Not Improve 10 km Swimming Intermittent Training

The aim of the present study was to test the effectiveness of carbohydrate (CHO) feeding supplemented every 2.5-km, as in official races, on the performance, rating of perceived exertion (RPE), and glycaemia during a 10-km intermittent training workout in elite open-water swimmers. A randomized crossover design was used. Participants completed two 10-km intermittent training sessions (20 × 500-m). The relative velocity was expressed in percentage of a single 500-m. Glycaemia was monitored by continuous glucose monitoring. Participants had to ingest either 1 L of tap water (WAT; 0.50 L·h⁻¹) or 120 g of CHO in the form of 8% solution (60 g·h⁻¹). The 15-point RPE scale was used during the trials. A two-way ANOVA for repeated measures was performed (p < 0.05). The relative velocity of each 500-m was not significantly different between the two trials. No significant differences emerged in the relative velocity of the last 500-m between trials. Average RPE was not statistically different between the two trials (11 ± 3 in WAT and 12 ± 3 in CHO). In the last 500-m, glycaemia was significantly higher in the CHO trial (5.92 ± 0.47 mmol·L⁻¹ in CHO; 5.61 ± 0.61 mmol·L⁻¹ in WAT). CHO ingestion did not improve performance or affect RPE during a 10-km intermittent training in elite open-water swimmers.

Respiratory frequency and tidal volume during exercise: differential control and unbalanced interdependence

Differentiating between respiratory frequency (fR ) and tidal volume (VT ) may improve our understanding of exercise hyperpnoea because fR and VT seem to be regulated by different inputs. We designed a series of exercise manipulations to improve our understanding of how fR and VT are regulated during exercise. Twelve cyclists performed an incremental test and three randomized experimental sessions in separate visits. In two of the three experimental visits, participants performed a moderate-intensity sinusoidal test followed, after recovery, by a moderate-to-severe-intensity sinusoidal test. These two visits differed in the period of the sinusoid (2 min vs. 8 min). In the third experimental visit, participants performed a trapezoidal test where the workload was self-paced in order to match a predefined trapezoidal template of rating of perceived exertion (RPE). The results collectively reveal that fR changes more with RPE than with workload, gas exchange, VT or the amount of muscle activation. However, fR dissociates from RPE during moderate exercise. Both VT and minute ventilation ( V ˙ E ) showed a similar time course and a large correlation with V ˙ CO 2 in all the tests. Nevertheless, V ˙ CO 2 was associated more with V ˙ E than with VT because VT seems to adjust continuously on the basis of fR levels to match V ˙ E with V ˙ CO 2 . The present findings provide novel insight into the differential control of fR and VT - and their unbalanced interdependence - during exercise. The emerging conceptual framework is expected to guide future research on the mechanisms underlying the long-debated issue of exercise hyperpnoea.

Whole body vibration of different frequencies inhibits H-reflex but does not affect voluntary activation

This study aimed to investigate the effects of whole-body vibration (WBV) at a frequency spectrum from 20 to 50 Hz on the Hoffmann (H) reflex and the voluntary motor output of ankle plantar-flexor muscles. A single-group (n: 8), repeated measures design was adopted with four conditions: standing (no vibration), 20, 35 and 50 Hz, each lasting one minute. H-reflex of the soleus muscle, maximal voluntary contraction (MVC) and central activation ratio (CAR) of the plantar-flexors were evaluated before, 1 and 5 min after each frequency condition. H-reflex decreased by 36.7% at 20 Hz, by 28% at 35 Hz, and by 34.8% at 50 Hz after one minute from WBV compared to baseline. Neither MVC nor CAR changed after WBV at all frequency conditions. The short-term, acute inhibition of the H-reflex after WBV at 20, 35 and 50 Hz suggested that decreased excitability of spinal motoneurons is not frequency dependent. On the other hand, the lack of vibration induced effects on MVC and CAR indicated that a 1-min WBV stimulus is not sufficient to affect the voluntary motor output.

Personalizing physical exercise in a computational model of fuel homeostasis

The beneficial effects of physical activity for the prevention and management of several chronic diseases are widely recognized. Mathematical modeling of the effects of physical exercise in body metabolism and in particular its influence on the control of glucose homeostasis is of primary importance in the development of eHealth monitoring devices for a personalized medicine. Nonetheless, to date only a few mathematical models have been aiming at this specific purpose. We have developed a whole-body computational model of the effects on metabolic homeostasis of a bout of physical exercise. Built upon an existing model, it allows to detail better both subjects' characteristics and physical exercise, thus determining to a greater extent the dynamics of the hormones and the metabolites considered.

Amniotic Membrane Transplantation Associated with Conjunctival Peritomy in the Management of Mooren's Ulcer: A Case Report

Purpose

To report the association of conjunctival peritomy with amniotic membrane transplantation (AMT) at the limbus with the exclusion of the central cornea in order to preserve visual function in one case of bilateral Mooren's ulcer.

Methods

A 36-year-old man with bilateral Mooren's ulcer was unresponsive to conventional therapy. Surgical procedure was performed on his right eye, at impending risk of corneal perforation. A 20 × 20 mm piece of amniotic membrane (AM) was prepared by performing a central hole of 7.5 mm diameter with a manual trephine. A 360° conjunctival peritomy was performed and the AM was placed with the epithelium side facing up and the central hole was sutured on the paracentral cornea.

Results

Two weeks after surgery, while the right eye showed improvement of signs and symptoms and unchanged best-corrected visual acuity (BCVA), the left eye showed a peripheral corneal perforation with prolapsed iris that required conjunctival flap. At 7 months of follow-up, the right eye showed no ocular inflammation, a reduction of the lipid-like peripheral corneal infiltrates, an increased stromal thickness, and an unchanged BCVA. The progression of corneal thinning in the left eye led the authors to perform AMT (as described) in the left eye as well. Five months after the AMT in the left eye, neither eye shows signs of disease progression, and neither requires further therapy.

Conclusions

Conjunctival peritomy associated with AMT may be an alternative surgical approach in the management of Mooren's ulcers to control the inflammation and the progression of disease.

Allergic conjunctivitis: current concepts on pathogenesis and management

Allergic conjunctivitis (AC) includes a wide spectrum of clinical entities characterized by different incidence, age of onset, natural course, clinical outcome and response to treatment. Taken together, they represent one of the most frequent ocular surface diseases affecting more than 30&#x0025; of the young-adult population and show an increasing incidence over the years. Moreover, comorbidities with other systemic atopic conditions such as asthma, atopic dermatitis and rhinitis require a multidisciplinary approach. Recent advances in the knowledge of the pathogenic mechanism overcome the classic role of type I hyper-sensitivity and mast cells’ activation, demonstrating an involvement of innate immunity and neuroinflammation in the pathogenesis of the most severe forms such as atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC). Ocular itching, swelling and tearing are the most frequent symptoms complained by patients with all forms of AC, while photophobia and pain are typical of the most severe forms, such as VKC and AKC, due to the frequent corneal involvement. Upper tarsal papillary reaction represents the main clinical sign of AC associated with conjunctival hyperemia and mucous secretion. Diagnosis is based on clinical history and eye evaluation and can be confirmed through allergological tests. Additional ocular exams include specific allergen conjunctival provocation tests and the presence of eosinophils in the conjunctival scraping. Current treatments of AC include the use of antiallergic eye drops for mild forms, while recurrences of ocular surface inflammations with corneal involvement in severe forms require the use of topical steroids to avoid visual impairment. Novel steroid sparing therapies such as Cyclosporine A eye drops or topical Tacrolimus have been proposed to improve VKC and AKC management.

Effect of a Behavioral Intervention Strategy for Adoption and Maintenance of a Physically Active Lifestyle: The Italian Diabetes and Exercise Study 2 (IDES_2): A Randomized Controlled Trial

OBJECTIVE

Adherence to physical activity (PA) recommendations is hampered by the lack of effective strategies to promote behavior change. The Italian Diabetes and Exercise Study 2 (IDES_2) is a randomized controlled trial evaluating a novel behavioral intervention strategy for increasing PA and decreasing sedentary time (SED-time) in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The study randomized 300 physically inactive and sedentary patients with type 2 diabetes 1:1 to receive theoretical and practical counseling once yearly for 3 years (intervention group [INT]) or standard care (control group [CON]). Here, we report the 4-month effects on objectively (accelerometer) measured daily light-intensity PA (LPA), moderate-to-vigorous-intensity PA (MVPA), and SED-time, and cardiovascular risk factors.

RESULTS

LPA and MVPA both increased, and SED-time decreased in both groups, although changes were significantly more marked in INT participants (approximately twofold for LPA and SED-time and approximately sixfold for MVPA). A significant reduction in HbA_1c was observed only in INT subjects. An increase in LPA >0.92 h · day^-1 and in MVPA >7.33 min · day^-1 and a decrease in SED-time >1.05 h · day^-1 were associated with an average decrease in HbA_1c of ∼1% and also with significant improvements in fasting glucose, body weight, waist circumference, and hs-CRP. Changes in PA and SED-time were independent predictors of improvements in HbA_1c.

CONCLUSIONS

This behavioral intervention is effective in the short term for increasing LPA and MVPA and reducing SED-time. Significant improvements in cardiometabolic risk profiles were observed in subjects experiencing the most pronounced changes in PA and SED-time, even if below the recommended level.

Effect of combined resistance and endurance exercise training on regional fat loss

BACKGROUND

The present study tested the possibility of a localized fat mass (FM) reduction by means of training programmes focusing on specific bodily regions.

METHODS

Sixteen physically inactive women (age: 31±4; BMI: 27.5±2.1), randomly allocated to two groups, completed an 8 week training programme. In one group (UpBdResist) training sessions consisted of upper body resistance exercises followed by 30-minute cycling at 50%VO2max, while the other group (LwBdResist) performed lower body resistance exercises followed by 30 minutes on an arm-ergometer. Regional body composition was assessed by DEXA and skin fold measures.

RESULTS

Regardless of a similar reduction in both groups, UpBdResist training elicited a greater reduction of the upper limbs (UL) FM as compared to the lower limbs (LL) (Δ% UL vs. LL: -12.1±3.4 vs. -4.0±4.7; P=0.02). Conversely, in the LwBdResist group, FM loss was more pronounced in the LL as compared to the UL (Δ% UL vs. LL: -2.3±7.0 vs. -11.5±8.2, P=0.02). Likewise, LwBdResist elicited a larger effect on lean mass (LM) of the LL as compared to UL (Δ% LL vs. UL: +8.4±5.8 vs. -2.7±5.0, P<0.01), yet no differences between upper and lower limb LM changes were detected in UpBdResist group.

CONCLUSIONS

The present data suggest that a training programme entailing localized explosive resistance exercise, prior to an endurance exercise bout, may target specific adipose tissue sites eliciting localised fat mass loss in the upper and lower limbs.

Role of Water Sorption in Tablet Crushing Strength, Disintegration, and Dissolution

Drugs formulated as tablets are subjected to accelerated stability conditions with the goal of identifying a stable formulation that will exhibit a sufficiently long shelf life. Water sorption at a condition such as 40°C/75% RH can result in significant changes in tablet properties such as a decrease in dissolution rate, the cause of which may be difficult to interpret, given the complex nature of ingredients and their interactions in a tablet. In this research, three drugs, displaying a wide range of physicochemical properties, were formulated with commonly used diluents, disintegrants, and binders, using a design of experiments approach. The tablets were stored at accelerated conditions and assessed for content, dissolution, disintegration, and crushing strength, as well as other properties. The research demonstrated many water-induced effects in tablet properties. Due to the experimental design approach that revealed many interactions, it was possible to interpret all of the changes observed in tablet crushing strength, disintegration, and dissolution for the drugs using a common set of physical principles. Specifically, the relevant factors considered were (1) mechanical properties of materials, (2) water sorption surface effects in surface diffusion and capillary condensation, (3) water sorption bulk effects for amorphous materials such as viscous flow/spreading, and (4) water-induced stress on interparticle bonding arising from volume expansion. These physical principles enable a comprehensive interpretation of the complex changes observed in tablet properties, which should be valuable in the design of tablet formulations that will be stable to accelerated storage conditions.

Differential control of respiratory frequency and tidal volume during high-intensity interval training

NEW FINDINGS

What is the central question of this study? By manipulating recovery intensity and exercise duration during high-intensity interval training (HIIT), we tested the hypothesis that fast inputs contribute more than metabolic stimuli to respiratory frequency (f_R ) regulation. What is the main finding and its importance? Respiratory frequency, but not tidal volume, responded rapidly and in proportion to changes in workload during HIIT, and was dissociated from some markers of metabolic stimuli in response to both experimental manipulations, suggesting that fast inputs contribute more than metabolic stimuli to f_R regulation. Differentiating between f_R and tidal volume may help to unravel the mechanisms underlying exercise hyperpnoea. Given that respiratory frequency (f_R ) has been proposed as a good marker of physical effort, furthering the understanding of how f_R is regulated during exercise is of great importance. We manipulated recovery intensity and exercise duration during high-intensity interval training (HIIT) to test the hypothesis that fast inputs (including central command) contribute more than metabolic stimuli to f_R regulation. Seven male cyclists performed an incremental test, a 10 and a 20 min continuous time trial (TT) as preliminary tests. Subsequently, recovery intensity and exercise duration were manipulated during HIIT (30 s work and 30 s active recovery) by performing four 10 min and one 20 min trial (recovery intensities of 85, 70, 55 and 30% of the 10 min TT mean workload; and 85% of the 20 min TT mean workload). The work intensity of the HIIT sessions was self-paced by participants to achieve the best performance possible. When manipulating recovery intensity, f_R , but not tidal volume (V_T ), showed a fast response to the alternation of the work and recovery phases, proportional to the extent of workload variations. No association between f_R and gas exchange responses was observed. When manipulating exercise duration, f_R and rating of perceived exertion were dissociated from V_T , carbon dioxide output and oxygen uptake responses. Overall, the rating of perceived exertion was strongly correlated with f_R (r = 0.87; P < 0.001) but not with V_T . These findings may reveal a differential control of f_R and V_T during HIIT, with fast inputs appearing to contribute more than metabolic stimuli to f_R regulation. Differentiating between f_R and V_T may help to unravel the mechanisms underlying exercise hyperpnoea.

The impact of type 1 diabetes and diabetic polyneuropathy on muscle strength and fatigability

AIMS

Although it is widely accepted that diabetic polyneuropathy (DPN) is linked to a marked decline in neuromuscular performance, information on the possible impact of type 1 diabetes (T1D) on muscle strength and fatigue remains unclear. The purpose of this study was to investigate the effects of T1D and DPN on strength and fatigability in knee extensor muscles.

METHODS

Thirty-one T1D patients (T1D), 22 T1D patients with DPN (DPN) and 23 matched healthy control participants (C) were enrolled. Maximal voluntary contraction (MVC) and endurance time at an intensity level of 50% of the MVC were assessed at the knee extensor muscles with an isometric dynamometer. Clinical characteristics of diabetic patients were assessed by considering a wide range of vascular and neurological parameters.

RESULTS

DPN group had lower knee extensor muscles strength than T1D (-19%) and the C group (-37.5%). T1D group was 22% weaker when compared to the C group. Lower body muscle fatigability of DPN group was 22 and 45.5% higher than T1D and C group, respectively. T1D group possessed a higher fatigability (29.4%) compared to C group. A correlation was found between motor and sensory nerve conduction velocity and muscle strength and fatigability.

CONCLUSIONS

Patients with T1D are characterised by both a higher fatigability and a lower muscle strength, which are aggravated by DPN. Our data suggest that factors other than nervous damage play a role in the pathogenesis of such defect.