Decrease of muscle fiber conduction velocity correlates with strength loss after an endurance run

Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated. After the run, knee extensors showed a decreased strength (-13  ±  9%, p  =  0.001) together with a reduction in EMG amplitude (-13  ±  10%, p  =  0.003) and in CV (-6  ±  8%, p  =  0.032). Knee extensor strength loss positively correlated with vastus lateralis CV differences (r  =  0.76, p  =  0.006). Thus, the exercises-induced muscle fatigue was associated not only with a decrease in EMG amplitude, but also with a reduction in CV. This finding suggests that muscle fibers with higher CV (i.e. those with greater fiber size) were the most impaired during strength production after an endurance run.

Age-Associated ALU Element Instability in White Blood Cells Is Linked to Lower Survival in Elderly Adults: A Preliminary Cohort Study

BACKGROUND

ALU element instability could contribute to gene function variance in aging, and may partly explain variation in human lifespan.

OBJECTIVE

To assess the role of ALU element instability in human aging and the potential efficacy of ALU element content as a marker of biological aging and survival.

DESIGN

Preliminary cohort study.

METHODS

We measured two high frequency ALU element subfamilies, ALU-J and ALU-Sx, by a single qPCR assay and compared ALU-J/Sx content in white blood cell (WBCs) and skeletal muscle cell (SMCs) biopsies from twenty-three elderly adults with sixteen healthy sex-balanced young adults; all-cause survival rates of elderly adults predicted by ALU-J/Sx content in both tissues; and cardiovascular disease (CVD)- and cancer-specific survival rates of elderly adults predicted by ALU-J/Sx content in both tissues, as planned subgroup analyses.

RESULTS

We found greater ALU-J/Sx content variance in WBCs from elderly adults than young adults (P < 0.001) with no difference in SMCs (P = 0.94). Elderly adults with low WBC ALU-J/Sx content had worse four-year all-cause and CVD-associated survival than those with high ALU-J/Sx content (both P = 0.03 and hazard ratios (HR) ≥ 3.40), while WBC ALU-J/Sx content had no influence on cancer-associated survival (P = 0.42 and HR = 0.74). SMC ALU-J/Sx content had no influence on all-cause, CVD- or cancer -associated survival (all P ≥ 0.26; HR ≤ 2.07).

CONCLUSIONS

These initial findings demonstrate that ALU element instability occurs with advanced age in WBCs, but not SMCs, and imparts greater risk of all-cause mortality that is likely driven by an increased risk for CVD and not cancer.

Mechanical energy patterns in nordic walking: comparisons with conventional walking

The use of poles during Nordic Walking (NW) actively engages the upper body to propel the body forward during walking. Evidence suggests that NW leads to a longer stride and higher speed, and sometimes to increased ground reaction forces with respect to conventional walking (W). The aim of this study was to investigate if NW is associated with different changes in body centre of mass (COM) motion and limbs energy patterns, mechanical work and efficiency compared to W. Eight experienced Nordic Walkers performed 5-min W and NW trials on a treadmill at 4kmh^-1. Steady state oxygen consumption and movements of body segments and poles were measured during each trial. We found greater fluctuation of kinetic (KE) and potential (PE) energy associated with COM displacement for NW compared to W. An earlier increase of KE for NW than for W, probably due to the propulsive action of poles, modified the synchronization between PE and KE oscillations so that a 10.9% higher pendular recovery between these energies was found in NW. The 10.2% higher total mechanical work found for NW was mainly due to the greater work required to move upper limbs and poles. NW was 20% less efficient and was metabolically more demanding than W, this difference could be ascribed to isometric contraction and low efficiency of upper musculature. Concluding, NW can be considered a highly dynamic gait, with distinctive mechanical features compared to conventional gait, due to pole propulsion and arm/pole swing.

Muscle damage and repeated bout effect induced by enhanced eccentric squats

BACKGROUND

Muscle damage and repeated bout effect have been studied after pure eccentric-only exercise. The aim of this study was to evaluate muscle damage and repeated bout effect induced by enhanced eccentric squat exercise using flywheel device.

METHODS

Thirteen healthy males volunteered for this study. Creatine kinase blood activity (CK), quadriceps isometric peak torque and muscle soreness were used as markers of muscle damage. The dependent parameters were measured at baseline, immediately after and each day up to 96 hours after the exercise session. The intervention consisted of 100 repetitions of enhanced eccentric squat exercise using flywheel device. The same protocol was repeated after 4 weeks.

RESULTS

After the first bout, CK and muscle soreness were significantly greater (P<0.05) than baseline respectively up to 72 and 96 hours. Isometric peak torque was significantly lower (P<0.05) up to 72 hours. After the second bout, CK showed no significant increase (P>0.05), while isometric peak torque and muscle soreness returned to values similar to baseline after respectively 48 and 72 hours. All muscle damage markers were significantly lower after second compared to first bout.

CONCLUSIONS

The enhanced eccentric exercise induced symptoms of muscle damage up to 96 hours. However, it provided muscle protection after the second bout, performed four weeks later. Although it was not eccentric-only exercise, the enhancement of eccentric phase provided muscle protection.

An Extreme Mountain Ultra-Marathon Decreases the Cost of Uphill Walking and Running

Purpose: To examine the effects of the world's most challenging mountain ultramarathon (MUM, 330 km, cumulative elevation gain of +24,000 m) on the energy cost and kinematics of different uphill gaits.

Methods: Before (PRE) and immediately after (POST) the competition, 19 male athletes performed three submaximal 5-min treadmill exercise trials in a randomized order: walking at 5 km·h⁻¹, +20%; running at 6 km·h⁻¹, +15%; and running at 8 km·h⁻¹, +10%. During the three trials, energy cost was assessed using an indirect calorimetry system and spatiotemporal gait parameters were acquired with a floor-level high-density photoelectric cells system.

Results: The average time of the study participants to complete the MUM was 129 h 43 min 48 s (range: 107 h 29 min 24 s to 144 h 21 min 0 s). Energy costs in walking (−11.5 ± 5.5%, P < 0.001), as well as in the first (−7.2 ± 3.1%, P = 0.01) and second (−7.0 ± 3.9%, P = 0.02) running condition decreased between PRE and POST, with a reduction both in the heart rate (−11.3, −10.0, and −9.3%, respectively) and oxygen uptake only for the walking condition (−6.5%). No consistent and significant changes in the kinematics variables were detected (P-values from 0.10 to 0.96).

Conclusion: Though fatigued after completing the MUM, the subjects were still able to maintain their uphill locomotion patterns noted at PRE. The decrease (improvement) in the energy costs was likely due to the prolonged and repetitive walking/running, reflecting a generic improvement in the mechanical efficiency of locomotion after ~130 h of uphill locomotion rather than constraints imposed by the activity on the musculoskeletal structure and function.

Changes in upper and lower body muscle involvement at increasing double poling velocities: an ecological study

This study evaluated muscle activity changes in different body compartments during on-snow double poling at increasing velocities. 21 well-trained, male cross-country skiers performed five 3-min double poling trials on a snowy track at 15, 16.5, 18, 19.5, and 21 km/h (set by an audio-pace system). A sixth trial was performed by maintaining a constant maximal speed. Actual skiing velocities were verified using a photocell system. Only 11 subjects met the pre-defined inclusion criteria during the trials and were included in the data analysis. Electromyographical signals from seven muscles, wrist acceleration and heart rate during the last minute of each trial were recorded. Cycle and poling times were measured from acceleration signals; mean muscular activation over a cycle was calculated for each muscle. With increasing double poling velocities from aerobic to maximal intensity (from 65% to 100% of maximal heart rate), upper limb muscles activation was maintained constant (P > 0.05), while trunk and lower limb involvement increased significantly (P < 0.01) with a linear trend. Rectus abdominis and rectus femoris muscles showed the higher rate of change. Trunk and lower limbs provide a progressively greater contribution to the propulsion when increasing double poling velocities are performed, to support the limited capacity of exercise response of upper body muscles. The remarkable rate of involvement of the muscles near the core region of the body becomes strategic to cope with the increased demands of propulsive power.

Velocity time integral for right upper pulmonary vein in VLBW infants with patent ductus arteriosus

OBJECTIVE:

Early diagnosis of significant patent ductus arteriosus reduces the risk of clinical worsening in very low birth weight infants. Echocardiographic patent ductus arteriosus shunt flow pattern can be used to predict significant patent ductus arteriosus. Pulmonary venous flow, expressed as vein velocity time integral, is correlated to ductus arteriosus closure. The aim of this study is to investigate the relationship between significant reductions in vein velocity time integral and non-significant patent ductus arteriosus in the first week of life.

METHODS:

A multicenter, prospective, observational study was conducted to evaluate very low birth weight infants (<1500 g) on respiratory support. Echocardiography was used to evaluate vein velocity time integral on days 1 and 4 of life. The relationship between vein velocity time integral and other parameters was studied.

RESULTS:

In total, 98 very low birth weight infants on respiratory support were studied. On day 1 of life, vein velocity time integral was similar in patients with open or closed ductus. The mean vein velocity time integral significantly reduced in the first four days of life. On the fourth day of life, there was less of a reduction in patients with patent ductus compared to those with closed patent ductus arteriosus and the difference was significant.

CONCLUSIONS:

A significant reduction in vein velocity time integral in the first days of life is associated with ductus closure. This parameter correlates well with other echocardiographic parameters and may aid in the diagnosis and management of patent ductus arteriosus.

High-intensity treadmill training improves gait ability, VO2peak and cost of walking in stroke survivors: preliminary results of a pilot randomized controlled trial

BACKGROUND

Stroke is a major cause of death and long-term disability across the globe. Previous studies have demonstrated the trainability of stroke survivors and documented beneficial effects of aerobic exercises on cardiovascular fitness and gait ability.

AIM

The main aim of this study was to compare the effects of a high-intensity treadmill training (HITT) against low-intensity treadmill training (LITT) on gait ability, quality of life, cardiorespiratory fitness and cost of walking in chronic stroke subjects.

DESIGN

Randomized, controlled pilot study.

SETTING

Patients were recruited among Neurorehabilitation Unit outpatient.

POPULATION

The sample was composed of 16 subjects suffering from chronic stroke.

METHODS

Subjects were enrolled and randomly allocated either in the HITT (N.=8) or in the LITT (N.=8). Both groups performed 3-month training, 3 times per week. Subjects were evaluated before starting the training and after the end of the training by mean of clinical scales (Six-Minute Walk Test, Ten-Meter Walk Test, Health Survey Questionnaire SF-36, Stroke Impact Scale) and instrumental tests (gait analysis, VO2peak and walking energy cost).

RESULTS

Fifteen subjects completed the study and no dropouts were observed. One patient in the LITT refused to initiate the training. The HITT group produced greater improvements than LITT group on the Six-Minute Walk Test (HITT: 64.25 meters, LITT: 6 meters; p=0.005) and Ten-Meter Walk Test performances (HITT: -1.7 s, LITT: 0.6 s; P=0.007), stride length (HITT: 3.3 cm, LITT: 0.4 cm, P=0.003), step length non-paretic side (HITT: 0.5 cm, LITT: 2.4 cm, P=0.008), step length paretic side (HITT: 1.8 cm, LITT: 0.7 cm, P=0.004), cadence (HITT: 1.6 step/min, LITT: 0.6 step/min, P=0.021) and symmetry ratio (HITT: 0.04 cm, LITT: 0.01 cm, P=0.004), VO2peak (HITT: 4.6 mL/kg/min, LITT: 0.87 mL/kg/min; P=0.015) and walking energy cost at 100% of self-selected speed (HITT: -30.8 mL/kg∙km, LITT: -20 5 mL/kg∙km; P=0.021). Significant changes were found on Six-Minute Walk Test (P=0.012) and Ten-Meter Walk Test (P=0.042) performances, spatio-temporal gait parameters (stride length P=0.011, step length paretic side P=0.012, cadence P=0.037 and symmetry ratio P=0.012), VO2peak (P=0.025) and cost of walking at 100% of self-selected speed (P=0.018) in the HITT group. In the LITT no significant results were observed.

CONCLUSIONS

HITT could be considered a feasible training and led to improvement in gait ability and enhanced VO2peak and reduction in cost of walking compared to LITT.

CLINICAL REHABILITATION IMPACT

Chronic stroke survivors should be encouraged to engage regular aerobic treadmill training at medium/high intensity. HITT is safe and feasible and has positive effects on gait ability, cardiovascular fitness and cost of walking in subjects with stroke in chronic phase.

Eccentric resistance training increases and retains maximal strength, muscle endurance, and hypertrophy in trained men

The aim of the present study was to evaluate the effects of different resistance training protocols on muscle strength, endurance, and hypertrophy after training and detraining. Thirty-four resistance-trained males were randomized in concentric-only (CONC), eccentric-only (ECC), traditional concentric-eccentric (TRAD) bench press resistance training or control group. The training volume was equalized among the intervention groups. Bench press of 1-repetition maximum (1RM)/body mass, maximum number of repetitions (MNR), and chest circumference were evaluated at the baseline, after 6 weeks of training, and after 6 weeks of detraining. All intervention groups reported significant 1RM/body mass increases after training (CONC baseline: 1.04 ± 0.06, post-training: 1.12 ± 0.08, p < 0.05; ECC baseline: 1.08 ± 0.04, post-training: 1.15 ± 0.05, p < 0.05; TRAD baseline: 1.06 ± 0.08, post-training: 1.11 ± 0.10, p < 0.05). After detraining, only ECC retained 1RM/body mass above the baseline (1.17 ± 0.07, p < 0.05), while CONC and TRAD returned to baseline values. Only ECC improved and retained MNR (baseline: 22 ± 3; post-training: 25 ± 3, and post-detraining: 25 ± 4, p < 0.05 compared with baseline) and chest circumference (baseline: 98.3 ± 2.4 cm, post-training: 101.7 ± 2.2 cm and post-detraining: 100.7 ± 2.3 cm. p < 0.05 compared with baseline), while no significant changes occurred in both CONC and TRAD. The incorporation of eccentric training can be recommended for counteracting the negative effects of detraining or forced physical inactivity.

Novelty in hypertension in children and adolescents: focus on hypertension during the first year of life, use and interpretation of ambulatory blood pressure monitoring, role of physical activity in prevention and treatment, simple carbohydrates and uric acid as risk factors

The present article intends to provide an update of the article "Focus on prevention, diagnosis and treatment of hypertension in children and adolescents" published in 2013 (Spagnolo et al., Ital J Pediatr 39:20, 2013) in this journal. This revision is justified by the fact that during the last years there have been several new scientific contributions to the problem of hypertension in pediatric age and during adolescence. Nevertheless, for what regards some aspects of the previous article, the newly acquired information did not require substantial changes to what was already published, both from a cultural and from a clinical point of view. We felt, however, the necessity to rewrite and/or to extend other parts in the light of the most recent scientific publications. More specifically, we updated and extended the chapters on the diagnosis and management of hypertension in newborns and unweaned babies, on the use and interpretation of ambulatory blood pressure monitoring, and on the usefulness of and indications for physical activity. Furthermore, we added an entirely new section on the role that simple carbohydrates (fructose in particular) and uric acid may play in the pathogenesis of hypertension in pediatric age.

DNA injury is acutely enhanced in response to increasing bulks of aerobic physical exercise

The aim of this study was to evaluate DNA damage in response to increasing bulks of aerobic physical exercise. Fifteen adult and trained athletes performed four sequential trials with increasing running distance (5-, 10-, 21- and 42-km) in different periods of the year. The γ-H2AX foci parameters were analyzed before and 3h after the end of each trial. The values of all γ-H2AX foci parameters were enhanced after the end of each trial, with values gradually increasing from the 5- to the 42-km trial. Interestingly, a minor increase of γ-H2AX foci was still evident after 5- to 10-km running, but a much higher increase occurred when the running distance exceeded 21km. The generation of DNA injury was then magnified by running up to 42-km. The increase of each γ-H2AX foci parameter was then found to be associated with both running distance and average intensity. In multivariate linear regression analysis, the running distance was significantly associated with average intensity and post-run variation in the percentage of cells with γ-H2AX foci. We can hence conclude that aerobic exercise may generate an acute DNA damage in trained athletes, which is highly dependent upon running distance and average intensity.

Possible Predictors of Involuntary Weight Loss in Patients with Alzheimer's Disease

Loss in body mass (∆BM) is a common feature in patients with Alzheimer’s disease (AD). However, the etiology of this phenomenon is unclear. The aim of this cohort study was to observe possible ∆BM in AD patients following a standard institutionalized diet. Secondary objective was to identify possible predictors of ∆BM. To this end, 85 AD patients (age: 76±4 yrs; stature: 165±3 cm; BM: 61.6±7.4 kg; mean±standard deviation) and 86 controls (CTRL; age: 78±5 yrs; stature: 166±4 cm; BM: 61.7±6.4 kg) were followed during one year of standard institutionalized diet (~1800 kcal/24h). BM, daily energy expenditure, albuminemia, number of medications taken, and cortisolism, were recorded PRE and POST the observation period. Potential predictors of ∆BM in women (W) and men (M) with AD were calculated with a forward stepwise regression model. After one year of standard institutionalized diet, BM decreased significantly in AD (-2.5 kg; p < 0.01), while in CTRL remained unchanged (-0.4 kg; p = 0.8). AD patients and CTRL exhibited similar levels of daily energy expenditure (~1625 kcal/24h). The combination of three factors, number of medications taken, albuminemia, and cortisolism, predicted ∆BM in W with AD. At contrary, the best predictor of ∆BM in M with AD was the cortisolism. Despite a controlled energy intake and similar energy expenditure, both W and M with AD suffered of ∆BM. Therefore, controlled diet did not prevent this phenomenon. The assessments of these variables may predict W and M with AD at risk of weight loss.

Central and peripheral fatigue in knee and elbow extensor muscles after a long-distance cross-country ski race

Although elbow extensors (EE) have a great role in cross-country skiing (XC) propulsion, previous studies on neuromuscular fatigue in long-distance XC have investigated only knee extensor (KE) muscles. In order to investigate the origin and effects of fatigue induced by long-distance XC race, 16 well-trained XC skiers were tested before and after a 56-km classical technique race. Maximal voluntary isometric contraction (MVC) and rate of force development (RFD) were measured for both KE and EE. Furthermore, electrically evoked double twitch during MVC and at rest were measured. MVC decreased more in KE (-13%) than in EE (-6%, P = 0.016), whereas the peak RFD decreased only in EE (-26%, P = 0.02) but not in KE. The two muscles showed similar decrease in voluntary activation (KE -5.0%, EE -4.8%, P = 0.61) and of double twitch amplitude (KE -5%, EE -6%, P = 0.44). A long-distance XC race differently affected the neuromuscular function of lower and upper limbs muscles. Specifically, although the strength loss was greater for lower limbs, the capacity to produce force in short time was more affected in the upper limbs. Nevertheless, both KE and EE showed central and peripheral fatigue, suggesting that the origins of the strength impairments were multifactorial for the two muscles.

Effects of eight weeks of aerobic interval training and of isoinertial resistance training on risk factors of cardiometabolic diseases and exercise capacity in healthy elderly subjects

We investigated the effect of 8 weeks of high intensity interval training (HIT) and isoinertial resistance training (IRT) on cardiovascular fitness, muscle mass-strength and risk factors of metabolic syndrome in 12 healthy older adults (68 yy ± 4). HIT consisted in 7 two-minute repetitions at 80%–90% of V˙O2max, 3 times/w. After 4 months of recovery, subjects were treated with IRT, which included 4 sets of 7 maximal, bilateral knee extensions/flexions 3 times/w on a leg-press flywheel ergometer. HIT elicited significant: i) modifications of selected anthropometrical features; ii) improvements of cardiovascular fitness and; iii) decrease of systolic pressure. HIT and IRT induced hypertrophy of the quadriceps muscle, which, however, was paralleled by significant increases in strength only after IRT. Neither HIT nor IRT induced relevant changes in blood lipid profile, with the exception of a decrease of LDL and CHO after IRT. Physiological parameters related with aerobic fitness and selected body composition values predicting cardiovascular risk remained stable during detraining and, after IRT, they were complemented by substantial increase of muscle strength, leading to further improvements of quality of life of the subjects.

Injury and Illness Rates During Ultratrail Running

This study aimed to describe injury/illness rates in ultratrail runners competing in a 65-km race to build a foundation for injury prevention and help race organizers to plan medical provision for these events. Prospectively transcribed medical records were analysed for 77 athletes at the end of the race. Number of injuries/illnesses per 1 000 runners and per 1 000-h run, overall injury/illness rate and 90% confidence intervals and rates for major and minor illnesses, musculoskeletal injuries, and skin disorders were analysed. A total of 132 injuries/illnesses were encountered during the race. The overall injuries/illnesses were 1.9 per runner and 13.1 per 1 000-h run. Medical illnesses were the most prominent medical diagnoses encountered (50.3%), followed by musculoskeletal injuries (32.8%), and skin-related disorders (16.9%). Despite the ultra-long nature of the race, the majority of injuries/illnesses were minor in nature. Medical staff and runners should prepare to treat all types of injuries and illnesses, especially the fatigue arising throughout the course of an ultratrail run and injuries to the lower limbs. Future studies should attempt to systematically identify injury locations and mechanisms in order to better direct injury prevention strategies and plan more accurate medical care.

Efficacy and safety of intravenous paracetamol in comparison to ibuprofen for the treatment of patent ductus arteriosus in preterm infants: study protocol for a randomized control trial

Background

Patent ductus arteriosus (PDA) is one of most common complications in preterm infants. Although ibuprofen represents the first choice for the closure of PDA, this treatment can cause severe gastrointestinal and adverse renal effects and worsen platelet function. The successful closure of the PDA with paracetamol has been recently reported in several preterm infants, and the safety of paracetamol for this use has been suggested by the available data.

Methods/design

We present the design of a randomized, multicenter, controlled study, whose aim is to assess the effectiveness and safety of intravenous paracetamol in comparison to intravenous ibuprofen for the treatment of PDA in preterm infants. A total of 110 infants born at 25⁺⁰ to 31⁺⁶ weeks of gestational age will be enrolled and randomized to receive paracetamol or ibuprofen (55 patients per group) starting at 24–72 h of life. The primary endpoint of the study is the comparison of the PDA closing rate observed after a 3-day course with paracetamol or ibuprofen. The secondary endpoints include the closure rate of PDA after the second course of treatment with ibuprofen, the re-opening rate of the PDA, the incidence of surgical ligation, and the occurrence of adverse effects.

Discussion

The results of this study will provide new information about the possible use of paracetamol in the treatment of PDA. Paracetamol could offer several important therapeutic advantages over current treatment options, and it could become the treatment of choice for the management of PDA, mainly due to its more favorable side effect profile.

Trial registration

Clinicaltrials.gov NCT02422966.

Eudract no. 2013-003883-30.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1294-4) contains supplementary material, which is available to authorized users.

Brief review of the state of art in futsal

Futsal (the official name of "five side indoor football") has become very popular in recent years, and it counts more than 12 million players in over 100 countries. Futsal is played on a field of 40 x 20 m between 2 teams of 5 players, (four outfield players and the goalkeeper). Despite its rise of popularity, the number of scientific studies related to training modalities as the demands of the match or factors linked to the performance, are quite limited. This brief review aims to explore the few papers published on futsal, taking in consideration some conclusions that can be drawn from previous studies related only to futsal and indoor football players. Future studies should examine the physical demands during the matches, the variation of physical performances during the season and compare different classic training modalities to sport specific exercises, aiming to improve the current knowledge for coaching.

The baseline serum value of α-amylase is a significant predictor of distance running performance

BACKGROUND

This study was planned to investigate whether serum α-amylase concentration may be associated with running performance, physiological characteristics and other clinical chemistry analytes in a large sample of recreational athletes undergoing distance running.

METHODS

Forty-three amateur runners successfully concluded a 21.1 km half-marathon at 75%-85% of their maximal oxygen uptake (VO2max). Blood was drawn during warm up and 15 min after conclusion of the run.

RESULTS

After correction for body weight change, significant post-run increases were observed for serum values of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, bilirubin, creatine kinase (CK), iron, lactate dehydrogenase (LDH), triglycerides, urea and uric acid, whereas the values of body weight, glomerular filtration rate, total and low density lipoprotein-cholesterol were significantly decreased. The concentration of serum α-amylase was unchanged. In univariate analysis, significant associations with running performance were found for gender, VO2max, training regimen and pre-run serum values of α-amylase, CK, glucose, high density lipoprotein-cholesterol, LDH, urea and uric acid. In multivariate analysis, only VO2max (p=0.042) and baseline α-amylase (p=0.021) remained significant predictors of running performance. The combination of these two variables predicted 71% of variance in running performance. The baseline concentration of serum α-amylase was positively correlated with variation of serum glucose during the trial (r=0.345; p=0.025) and negatively with capillary blood lactate at the end of the run (r=-0.352; p=0.021).

CONCLUSIONS

We showed that the baseline serum α-amylase concentration significantly and independently predicts distance running performance in recreational runners.

Effects of short-term fatigue on biomechanical and physiological aspects of double poling in high-level cross-country skiers

The study aim was to evaluate biomechanical and physiological alterations in double poling technique (DP) after a short-term fatiguing exercise. Eight high-level skiers performed a sub-maximal DP trial (20kmh(-1), 1°) before (PRE) and after (POST) a DP test to exhaustion while roller skiing on a treadmill. An integrated analysis of DP technique during PRE and POST included measurement of pole, joint, and centre of mass (COM) kinematics, poling forces, cycle timing, and metabolic parameters. Muscle fatigue in three upper-body muscles was assessed by calculating the Dimitrov' fatigue index (FInms5) of specific electromyographic segments. FInms5 tended to increase in the latissimus dorsi and teres major muscles (P=0.023 and P=0.030, respectively) across consecutive DP cycles, as did blood lactate concentration (P=0.001) and rating of perceived exertion (P=0.005). The changes indicated a state of fatigue during POST and coincided with the reduction in poling force exertion capacity (P=0.020). Pole, joint and COM kinematics did not differ between PRE and POST (P>0.050), whereas recovery phase and cycle times were shorter at POST (P<0.001 and P=0.001, respectively). Short-term fatigue led to a reduction in poling force exertion capacity and cycle time in high-level skiers, without altering body and pole kinematics.

Rest Rust ! Physical active for active and healthy ageing

The aim of this paper is to give an insight on how physical activity can be defined, parameterized and measured in older adults and on different options to deal with citizen physical activity promotion at European level. Three relevant aspects are highlighted: When talking about physical activity, two different aspects are often unfairly mixed up: "physical activity" and "physical capacity". Physical activity, is referred to as the level of physical activity someone is actually performing in daily life.Physical capacity is referred to as the maximum physical activity a person can perform.Both physical activity and physical capacity can be expressed in different dimensions such as time, frequency, or type of activity with the consequence that there are many tools and techniques available. In order to support people to choose an appropriate instrument in their everyday practice a list of 9 criteria that are considered important is defined.Older adults score differently across the various physical dimensions, so strategies to promote physical activity should consider individual differences, in order to adapt for these variations.

Serum testosterone predicts cardiorespiratory fitness impairment in normal-weight women with polycystic ovary syndrome

OBJECTIVE

Limited literature has shown that maximal oxygen consumption (V'O2max), that is the maximal capacity of an individual to perform aerobic work, may be lowered in overweight/obese women with polycystic ovary syndrome (PCOS). However, it remains unclear whether this impairment is associated with PCOS per se or is entirely due to body fat excess. Our objective was to assess whether cardiorespiratory fitness is altered in normal-weight PCOS women and to investigate which factors are associated with this phenomenon.

SUBJECTS

Fifteen normal-weight PCOS women and 15 age- and BMI-matched healthy controls. Fourteen subjects in each group completed the protocol.

MEASUREMENTS

V'O2max and ventilatory thresholds (maximal incremental cycle ergometer test with breath-by-breath analysis of gas exchange), insulin sensitivity (hyperinsulinaemic euglycaemic clamp) and androgenaemia (serum total and free testosterone, measured by liquid chromatography mass spectrometry and equilibrium dialysis) were accurately assessed.

RESULTS

Maximal V'O2 and power were strikingly impaired in normal-weight PCOS individuals, as compared with healthy controls (29·4 ± 1·5 vs 35·8 ± 1·6 ml O2/kg/min, P = 0·008; 138 ± 6 vs 170 ± 10 W, P = 0·011, respectively). Similarly, oxygen consumption and power at both the first and second ventilatory thresholds were significantly lower in PCOS subjects than in healthy women. In multiple regression analysis, V'O2max was negatively predicted by serum-free testosterone levels, but not by body fat mass and glucose disposal rate (R(2) = 0·45 P = 0·013).

CONCLUSIONS

Cardiorespiratory fitness is impaired in normal-weight PCOS women. Androgen excess but not insulin sensitivity is associated with this alteration.

The increase in hydric volume is associated to contractile impairment in the calf after the world's most extreme mountain ultra-marathon

Background

Studies have recently focused on the effect of running a mountain ultra-marathon (MUM) and their results show muscular inflammation, damage and force loss. However, the link between peripheral oedema and muscle force loss is not really established. We tested the hypothesis that, after a MUM, lower leg muscles’ swelling could be associated with muscle force loss. The knee extensor (KE) and the plantar flexor (PF) muscles’ contractile function was measured by supramaximal electrical stimulations, potentiated low- and high-frequency doublets (PS10 and PS100) of the KE and the PF were measured by transcutaneous electrical nerve stimulation and bioimpedance was used to assess body composition in the runners (n = 11) before (Pre) and after (Post) the MUM and compared with the controls (n = 8).

Results

The maximal voluntary contraction of the KE and the PF significantly decreased by 20 % Post-MUM in the runners. Hydration of the non-fat mass (NF-Hyd) and extracellular water volume (Ve) were increased by 12 % Post-MUM (p < 0.001) in the runners. Calf circumference (+2 %, p < 0.05) was also increased. Significant relationships were found for percentage increases in Ve and NF-Hyd with percentage decrease in PS10 of the PF (r = −0.68 and r = −0.70, p < 0.05) and with percentage increase of calf circumference (r = 0.72 and r = 0.73, p < 0.05) in the runners.

Conclusions

The present study suggests that increases in circumference and in hydric volume are associated to contractile impairment in the calf in ultra-marathon runners.

Effects of endurance, circuit, and relaxing training on cardiovascular risk factors in hypertensive elderly patients

Recommendations for prevention of cardiovascular diseases (CVDs) risk factors among older adults highlighted the importance of exercise-based interventions, including endurance training (ET). However, the evidence of efficacy of other interventions based on short-bouts of exercise (circuit training, CT), and the practice of breath-control and meditation (relaxing training, RT) is growing. The aim of this study was to elucidate if CT or RT are equally effective in CVD risk factors reduction compared to ET. To this purpose, in 40 elderly participants, with clinically diagnosed grade 1 hypertension, resting blood pressure, blood glucose, and cholesterol levels, peak oxygen uptake ([Formula: see text]), mechanical efficiency and quality of life were evaluated before and after 12 weeks of ET, CT, and RT treatments. Resting blood pressure reduced significantly in all groups by ∼11 %. In ET, blood cholesterol levels (-18 %), [Formula: see text] (+8 %), mechanical efficiency (+9 %), and quality of life scores (+36 %) ameliorated. In CT blood glucose levels (-11 %), [Formula: see text] (+7 %) and quality of life scores (+35 %) were bettered. Conversely, in RT, the lower blood pressure went along only with an improvement in the mental component of quality of life (+42 %). ET and CT were both appropriate interventions to reduce CVDs risk factors, because blood pressure reduction was accompanied by decreases in blood glucose and cholesterol levels, increases in [Formula: see text], mechanical efficiency, and quality of life. Although RT influenced only blood pressure and quality of life, this approach would be an attractive alternative for old individuals unable or reluctant to carry out ET or CT.

Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking

Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

In vivo and in vitro evidence that intrinsic upper- and lower-limb skeletal muscle function is unaffected by ageing and disuse in oldest-old humans

AIM

To parse out the impact of advanced ageing and disuse on skeletal muscle function, we utilized both in vivo and in vitro techniques to comprehensively assess upper- and lower-limb muscle contractile properties in 8 young (YG; 25 ± 6 years) and 8 oldest-old mobile (OM; 87 ± 5 years) and 8 immobile (OI; 88 ± 4 years) women.

METHODS

In vivo, maximal voluntary contraction (MVC), electrically evoked resting twitch force (RT), and physiological cross-sectional area (PCSA) of the quadriceps and elbow flexors were assessed. Muscle biopsies of the vastus lateralis and biceps brachii facilitated the in vitro assessment of single fibre-specific tension (Po).

RESULTS

In vivo, compared to the young, both the OM and OI exhibited a more pronounced loss of MVC in the lower limb [OM (-60%) and OI (-75%)] than the upper limb (OM = -51%; OI = -47%). Taking into account the reduction in muscle PCSA (OM = -10%; OI = -18%), only evident in the lower limb, by calculating voluntary muscle-specific force, the lower limb of the OI (-40%) was more compromised than the OM (-13%). However, in vivo, RT in both upper and lower limbs (approx. 9.8 N m cm(-2) ) and Po (approx. 123 mN mm(-2) ), assessed in vitro, implies preserved intrinsic contractile function in all muscles of the oldest-old and were well correlated (r = 0.81).

CONCLUSION

These findings suggest that in the oldest-old, neither advanced ageing nor disuse, per se, impacts intrinsic skeletal muscle function, as assessed in vitro. However, in vivo, muscle function is attenuated by age and exacerbated by disuse, implicating factors other than skeletal muscle, such as neuromuscular control, in this diminution of function.

A case report of aorto-pulmonary window in an infant born to a diabetic mother

Several studies have described the association between pre-gestational maternal diabetes and cardiac disease in the newborn. Infants of diabetic mothers have an increased incidence of congenital heart disease, reported between 3% and 6% compared to 0.8% of the general population. A particularly high prevalence of conotruncal defects has been recently described among congenital heart diseases. This group of malformations affects ventricular outflows, aorta, and pulmonary artery and shares a common embryogenic origin. They include persistence of the truncus arteriosus, transposition of great arteries, tetralogy of Fallot, interruption of the aortic arch, and double outlet right ventricle. Aorto-pulmonary window, a rare congenital heart disease belonging to conotruncal malformations, has never been previously described in association with maternal diabetes. We describe the case of a male infant born to a mother suffering from a poorly controlled type 1 diabetes during pregnancy. In the early postnatal life the infant showed respiratory distress, tachycardia, and failure to thrive. He was found to be affected by aorto-pulmonary window that required corrective surgical intervention. <Learning objective: This case report warns us to consider this congenital abnormality as a possible finding in infants born to a diabetic mother. Furthermore, it shows how difficult the echocardiographic diagnosis of aorto-pulmonary windows can be.>.

Gait models and mechanical energy in three cross-country skiing techniques

Fluctuations in mechanical energy of the body center of mass (COM) have been widely analyzed when investigating different gaits in human and animal locomotion. We applied this approach to estimate the mechanical work in cross-country skiing and to identify the fundamental mechanisms of this particular form of locomotion. We acquired movements of body segments, skis, poles and plantar pressures for eight skiers while they roller skied on a treadmill at 14 km h(-1) and a 2 deg slope using three different techniques (diagonal stride, DS; double poling, DP; double poling with kick, DK). The work associated with kinetic energy (KE) changes of COM was not different between techniques; the work against gravity associated with potential energy (PE) changes was higher for DP than for DK and was lowest for DS. Mechanical work against the external environment was 0.87 J m(-1) kg(-1) for DS, 0.70 J m(-1) kg(-1) for DP and 0.79 J m(-1) kg(-1) for DK. The work done to overcome frictional forces, which is negligible in walking and running, was 17.8%, 32.3% and 24.8% of external mechanical work for DS, DP and DK, respectively. The pendulum-like recovery (R%) between PE and KE was ~45%, ~26% and ~9% for DP, DK and DS, respectively, but energy losses by friction are not accounted for in this computation. The pattern of fluctuations of PE and KE indicates that DS can be described as a 'grounded running', where aerial phases are substituted by ski gliding phases, DP can be described as a pendular gait, whereas DK is a combination of both.

Acute Exercise Increases Sex Differences in Amateur Athletes' Risk Taking

The research presented here investigates the interaction between acute exercise, biological sex and risk-taking behavior. The study involved 20 amateur athletes (19-33 years old), 10 males and 10 females, who were asked to undergo subsequent experimental sessions designed to compare their risky behaviors on the Balloon Analogue Risk Task (BART) 34 at rest and while exercising at moderate intensity (60% of their maximal aerobic power). Results showed that physical exercise affected male and female participants differently: Whereas males became more risk seeking, females became more risk averse during exercise.

Association between Hemodynamically Significant Patent Ductus Arteriosus and Bronchopulmonary Dysplasia

OBJECTIVE

To assess whether the duration and magnitude of the shunt with patent ductus arteriosus (PDA) are related to a higher incidence of bronchopulmonary dysplasia (BPD) or death.

STUDY DESIGN

A total of 242 infants ≤ 28 weeks gestational age were evaluated retrospectively between 2007 and 2012; 105 (43.3%) developed BPD or died (group 1) and 137 (56.6%) did not (group 2). A review of all echocardiographic evaluations performed from birth up to 36 weeks of postconceptional age or final ductal closure was carried out, to detect the presence of PDA, and estimate the severity of ductal shunt through the "PDA staging system" proposed by McNamara and Sehgal.

RESULTS

Group 1 presented with a hemodynamically significant ductus arteriosus (DA) (E3 and/or E4-PDA) for a longer period of time vs group 2: 4.8 vs 2.3 days, respectively (P < .001). Persistence of a nonsignificant DA (E2) was not associated with development of BPD (P = .16). Each week of a hemodynamically significant DA represented an added risk for BPD (OR 1.7), and the duration of a small, nonsignificant DA (E2) did not. Surgical ligation of PDA itself was not found to be an independent risk factor for BPD. In the subgroup of patients who received ligation, a later ligation (33 vs 23 days) and a prolonged PDA were the only factors associated to BPD or death.

CONCLUSIONS

A shared scoring system of the severity of ductal shunt is helpful to correctly evaluate the association between PDA morbidities, to compare scientific studies, and to guide treatment.

Does the Pisa syndrome affect postural control, balance, and gait in patients with Parkinson's disease? An observational cross-sectional study

INTRODUCTION

An altered sense of verticality, associated with impaired proprioception and somatosensory integration deficits, has been reported in patients with Parkinson's disease (PD) but it has not been characterized in patients with Pisa syndrome (PS). Therefore, we investigated postural control, balance, and gait disturbances in patients with PD and PS, patients with PD but without PS, and aged-matched normal controls.

METHODS

This observational cross-sectional study involved patients with PD and PS (n = 10, Hoehn & Yahr score <4), patients with PD but without PS (n = 10), and age-matched healthy controls (n = 10). The primary outcome measure was the velocity of CoP displacement (VEL_MED_AP/ML) assessed by static stabilometry in eyes open (EO) and eyes closed (EC) conditions. The secondary outcomes were other stabilometric parameters, the Sensory Organization Balance Test (SOT), and gait analysis (GA).

RESULTS

There were no significant differences in demographic and clinical data and Berg Balance Scale scores between the groups. There was a significant main effect in the VEL_MED_AP/ML between the groups and eye conditions (p = .016). A significant main effect was found in the EO (p = .01) and EC (p = .04) conditions. Post-hoc comparisons showed a significant increase in VEL_CoP in both the EO and EC conditions only in the patients with PD and PS. No significant main effects on SOT and GA were found.

CONCLUSION

Patients with PD and PS had more difficulty achieving good postural alignment with gravity and greater velocity of body sway than the other groups. Rehabilitation programs for patients with PD and PS should include spine alignment and dynamic postural training.

Mini-open incision for distal biceps repair by suture anchors: follow-up of eighteen patients

BACKGROUND

This clinical trial was done to describe a mini approach for distal biceps repair using two or three suture anchors.

PATIENTS AND METHODS

Twenty patients have undergone surgical repair over the last 10 years. All patients were males with mean age 46.8 (range 35-72), and dominant arm was involved in 70 %. Eighteen patients were evaluated with subjective and objective criteria including patient's satisfaction, active range of motion (ROM), and maximum isometric strength (in supination and flexion) using Cybex dynamometer. Functional scoring included Mayo Elbow Performance Score, Disabilities of the Arm, Shoulder and Hand score and Oxford Elbow Score.

RESULTS

Eighty percent of patients were highly satisfied, with excellent results as defined by Mayo and Oxford Elbow score. Compared to contralateral, the active ROM was not affected in flexion and extension, but pronation and supination were decreased by 5°-10° in two cases. One of eighteen showed hypoesthesia of first and second fingers, and one of eighteen showed a symptomatic heterotopic ossification. There were no reruptures.

CONCLUSIONS

Surgical repair of distal biceps tendon with a mini-single-incision as we described provides patient's satisfaction and very good results with respect to ROM and functional scoring, with a low complication rate.

Energetics and biomechanics of double poling in regional and high-level cross-country skiers

PURPOSE

The aim of this study was to evaluate the energetics and the biomechanics of double poling technique (DP) in two groups of cross-country skiers.

METHODS

Eight high-level (HLG) and eight regional-level (RLG) skiers performed a 5-min sub-maximal DP trial, roller skiing on a treadmill at 14 km h(-1) and 2°. Energetic cost (ECDP), center of mass (COM) vertical displacement range, body inclination (θ, i.e., the angle between the vertical line and the line passing through COM and a fixed pivot point identified at feet level) and mechanical work associated to COM motion were analyzed. Pole and joint kinematics, poling forces and cycle timing were also considered.

RESULTS

HLG showed lower ECDP than RLG, smaller COM vertical displacement range and mechanical work, whereas higher θ during the early part of the poling phase (P < 0.05). In HLG, pole inclination was higher, poling forces greater and cycle duration longer (P < 0.05). Considering all skiers, a forward multiple regression revealed that the maximum value of θ (θ max) and the minimum value of COM vertical displacement resulted the COM-related parameters that better predict ECDP (AdjR (2) = 0.734; P < 0.001). Moreover, θ max positively related to poling force integrals and cycle duration (P < 0.05).

CONCLUSIONS

A pronounced body inclination during the early poling phase and a reduced COM vertical displacement range concur in explaining the differences in ECDP found between the groups and among the skiers. A mechanically advantageous motion of COM during DP improves poling effectiveness, reduces cycle frequency and the mechanical work sustained.