Classification of Intensity in Team-Sport Activity

AbstractPurposeTo assess the efficacy of critical metabolic power derived from variable-speed movement for classifying intensity in team sport activity.MethodsElite male hockey players (n = 12) completed a series of time trials (100 yd, 400 yd, 1500 yd) and a 3-min all-out test to derive both critical speed (CS) and critical power (CP). Heart rate (HR), blood lactate (BLa) and rating of perceived exertion (RPE) were measured during each protocol. Participants (n = 10) then played 2 competitive hockey matches. Time spent >85% of HRmax was compared to time spent above CS (from the time trials) and CP (from the 3-min test).ResultsBetween protocols, there was a moderate and non-significant association for CS (r = 0.359, P = 0.252), and a very large association for CP (r = 0.754, P = 0.005); the association was very large for peak HR (r = 0.866, P 85% HRmax and time spent above both CS (r = 0.719, P 85% of HRmax was compared to time spent above CS (from the time trials) and CP (from the 3-min test). Results Between protocols, there was a moderate and non-significant association for CS (r = 0.359, P = 0.252), and a very large association for CP (r = 0.754, P = 0.005); the association was very large for peak HR (r = 0.866, P 85% HRmax and time spent above both CS (r = 0.719, P

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Let the Pleasure Guide Your Resistance Training Intensity

ABSTRACTPurposeThe purpose of this study was to evaluate the feasibility and reliability of the Feeling Scale (FS) to self-regulate resistance training (RT) intensity.MethodsSixteen sedentary men (39.7±7.5 years) performed 3 familiarization sessions, 2 one repetition maximum testing (1RM), and 16 RT sessions (4 sessions for each FS descriptor; randomized). The FS descriptors were "very good" (FS+5), "good" (FS+3), "fairly good" (FS+1), and "fairly bad" (FS-1). Resistance exercises were leg press, chest press, knee extension, and seated biceps curl. Participants were instructed to select a load associated with the verbal/numerical descriptor of the FS to perform 3 sets of 10 repetitions.ResultsParticipants lifted a significantly greater %1RM as the FS level decreased from FS+5 to FS-1 (P

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Exercise Improves Physical Activity and Comorbidities in Obese Adults with Asthma

ABSTRACTIntroductionObese adults with asthma have an increased number of comorbidities and reduced daily life physical activity (DLPA), which may worsen asthma symptoms. Exercise is recommended to improve asthma outcomes; however, the benefits of exercise for psychosocial comorbidities and physical activity levels in obese adults with asthma have been poorly investigated.ObjectiveTo assess the effects of exercise on DLPA, asthma symptoms and psychosocial comorbidities in obese adults with asthma.MethodsFifty-five grade II obese adults with asthma were randomly assigned to either a weight-loss program+exercise program (WL+E group, n=28) or a weight-loss program+sham (WL+S group, n=27). The WL+E group incorporated aerobic and resistance muscle training into the weight-loss program (nutrition and psychological therapies), while the WL+S group performed breathing and stretching exercises. DLPA, asthma symptoms, sleep quality and anxiety and depression symptoms were quantified before and after treatment.ResultsAfter 3 months, the WL+E group presented a significant increase in daily step counts (3,068 ± 2,325 vs. 729 ± 1,118 steps/day) and the number of asthma-symptom-free days (14.5 ± 9.6 vs. 8.6 ± 11.4 d/mo) compared with the WL+S group. The proportion of participants with improvements in depression symptoms (76.4 vs. 16.6 %) and a lower risk of developing obstructive sleep apnea (56.5 vs. 16.3%) was greater in the WL+E group than in the WL+S group (P

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Changes in Motor Coordination Induced by Local Fatigue during a Sprint Cycling Task

AbstractPurposeThis study investigated how muscle coordination is adjusted in response to a decrease in the force-generating capacity of one muscle group during a sprint cycling task.MethodsFifteen participants were tested during a sprint before and after a fatigue electromyostimulation protocol was conducted on the quadriceps of one leg. Motor coordination was assessed by measuring myoelectrical activity, pedal force and joint power.ResultsThe decrease in force-generating capacity of the quadriceps (-28.0±6.8%) resulted in a decrease in positive knee extension power during the pedaling task (-34.4±30.6 W; P=0.001). The activity of the main non-fatigued synergist and antagonist muscles (triceps surae, gluteus maximus and hamstrings) of the ipsilateral leg decreased, leading to a decrease in joint power at the hip (-30.1±37.8 W; P=0.008) and ankle (-20.8±18.7 W; P=0.001). However, both the net power around the knee and the ability to effectively orientate the pedal force were maintained during the extension by reducing the co-activation and the associated negative power produced by the hamstrings. Adaptations also occurred in flexion phases in both legs, exhibiting an increased power (+17.9±28.3 [P=0.004] and +19.5 ± 21.9 W [P=0.026]), associated with an improvement in mechanical effectiveness.ConclusionThese results demonstrate that the nervous system readily adapts coordination in response to peripheral fatigue by i) decreasing the activation of adjacent non-fatigued muscles to maintain an effective pedal force orientation (despite reducing pedal power) and ii) increasing the neural drive to muscles involved in the flexion phases such that the decrease in total pedal power is limited. Purpose This study investigated how muscle coordination is adjusted in response to a decrease in the force-generating capacity of one muscle group during a sprint cycling task. Methods Fifteen participants were tested during a sprint before and after a fatigue electromyostimulation protocol was conducted on the quadriceps of one leg. Motor coordination was assessed by measuring myoelectrical activity, pedal force and joint power. Results The decrease in force-generating capacity of the quadriceps (-28.0±6.8%) resulted in a decrease in positive knee extension power during the pedaling task (-34.4±30.6 W; P=0.001). The activity of the main non-fatigued synergist and antagonist muscles (triceps surae, gluteus maximus and hamstrings) of the ipsilateral leg decreased, leading to a decrease in joint power at the hip (-30.1±37.8 W; P=0.008) and ankle (-20.8±18.7 W; P=0.001). However, both the net power around the knee and the ability to effectively orientate the pedal force were maintained during the extension by reducing the co-activation and the associated negative power produced by the hamstrings. Adaptations also occurred in flexion phases in both legs, exhibiting an increased power (+17.9±28.3 [P=0.004] and +19.5 ± 21.9 W [P=0.026]), associated with an improvement in mechanical effectiveness. Conclusion These results demonstrate that the nervous system readily adapts coordination in response to peripheral fatigue by i) decreasing the activation of adjacent non-fatigued muscles to maintain an effective pedal force orientation (despite reducing pedal power) and ii) increasing the neural drive to muscles involved in the flexion phases such that the decrease in total pedal power is limited. Correspondence and reprints: Sylvain DOREL, PhD, University of Nantes, Laboratory "Motricité, Interactions, Performance" (EA4334), 25 bis boulevard Guy Mollet, BP 72206, 44322 Nantes cedex 3, France. Email: sylvain.dorel@univ-nantes.fr Project support was provided by the Region Pays de la Loire (ANOPACy project) and the French Ministry of Sport (14-R-23). Francois Hug was supported by a fellowship from the Institut Universiatire de France (IUF). The authors report no conflict of interest. The results of the present study do not constitute endorsement by the American College of Sports Medicine. The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation Accepted for Publication: 6 February 2018 © 2018 American College of Sports Medicine

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Dexmedetomidine as a part of general anaesthesia for caesarean delivery in patients with pre-eclampsia: Efficacy and foetal outcome a randomised double-blinded trial

BACKGROUND During general anaesthesia, endotracheal intubation of patients with pre-eclampsia causes stimulation of the sympathetic nervous system and catecholamine release, which may lead to maternal and neonatal complications. OBJECTIVE To attenuate both the stress response and the haemodynamic response to tracheal intubation in patients with pre-eclampsia. DESIGN A randomised, double-blind, controlled study. SETTING Single University Hospital. PATIENTS Sixty patients aged 18 to 45 years with pre-eclampsia receiving general anaesthesia for caesarean section. INTERVENTIONS The patients were randomly allocated to three groups. Groups D1and D2 received an infusion of dexmedetomidine 1 μg kg−1 over the 10 min before induction of general anaesthesia, then 0.4 and 0.6 μg kg−1 h−1 dexmedetomidine, respectively. Group C received equivalent volumes of 0.9% saline. MAIN OUTCOME MEASURES The primary outcome was the effect of dexmedetomidine on mean arterial blood pressure measured before induction of general anaesthesia at 1 and 5 min after intubation, and then every 5 min until 10 min after extubation. The secondary outcomes were blood glucose and serum cortisol (measured before induction of general anaesthesia, and at 1 and 5 min after intubation), postoperative visual analogue pain scores, time to first request for analgesia, the total consumption of analgesia, Ramsay sedation score, maternal and placental vein blood serum levels of dexmedetomidine and neonatal Apgar score at 1 and 5 min. RESULTS At all assessment times, the mean arterial pressures were significantly lower in the dexmedetomidine groups than in the control group. Compared with group C, the heart rate was significantly lower in both groups D1 and D2. In group D2, the heart rate was lower than in group D1. Serum glucose and cortisol were significantly higher in the controls than in either group D1 or D2. Group D2 patients were significantly more sedated on arrival in the recovery room followed by D1. Time to first analgesia was significantly longer in groups D2 and D1 than in group C, and the visual analogue pain scores were significantly lower in groups D1 and D2 than in group C at 1, 2, 3 and 5 h. Total morphine consumption was significantly lower in groups D1 and D2 than in the control group. There was no difference in Apgar scores across the three groups despite significantly higher dexmedetomidine concentrations in group D2 (both maternal and placental vein) than in group D1. CONCLUSION Administration of dexmedetomidine in doses 0.4 and 0.6 μg kg−1 h−1 was associated with haemodynamic and hormonal stability, without causing significant adverse neonatal outcome. TRIAL REGISTRATION Pan African Clinical Trial Registry (PACTR201706002303170), (www.pactr.org). Correspondence to Ashraf M. Eskandr, MD, Department of Anesthesia, ICU and Pain Therapy, Faculty of Medicine, Menoufiya University, 3 Yassin Abd-Elghafar Street, Shibin El-koom, Egypt E-mail: ameskandr@yahoo.com © 2018 European Society of Anaesthesiology

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Low anaesthetic waste gas concentrations in postanaesthesia care unit: A prospective observational study

BACKGROUND Volatile anaesthetics are a potential hazard during occupational exposure, pregnancy or in individuals with existing disposition to malignant hyperthermia. Anaesthetic waste gas concentration in postanaesthesia care units (PACU) has rarely been investigated. OBJECTIVE(S) The current study aims to assess concentrations of volatile anaesthetics in relation to room size, number of patients and ventilator settings in different PACUs. DESIGN A prospective observational study. SETTING Two different PACUs of the Hannover Medical School (Hannover, Germany) were evaluated in this study. The rooms differed in dimensions, patient numbers and room ventilation settings. PATIENTS During the observation period, sevoflurane anaesthesia was performed in 65 of 140 patients monitored in postanaesthesia unit one and in 42 of 70 patients monitored in postanaesthesia unit two. MAIN OUTCOME MEASURES Absolute trace gas room concentrations of sevoflurane measured with a compact, closed gas loop high-resolution ion mobility spectrometer. RESULTS Traces of sevoflurane could be detected in 805 out of 970 samples. Maximum concentrations were 0.96 ± 0.20 ppm in postanaesthesia unit one, 0.82 ± 0.07 ppm in postanaesthesia unit two. Median concentration was 0.12 (0.34) ppm in postanaesthesia unit one and 0.11 (0.28) ppm in postanaesthesia unit two. CONCLUSION Low trace amounts of sevoflurane were detected in both PACUs equipped with controlled air exchange systems. Occupational exposure limits were not exceeded. Correspondence to Dr. Sebastian Heiderich, MD, Clinic of Anaesthesiology and Intensive Care Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany E-mail: heiderich.sebastian@mh-hannover.de © 2018 European Society of Anaesthesiology

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Low perfusion pressure is associated with renal tubular injury in infants undergoing cardiac surgery with cardiopulmonary bypass: A secondary analysis of an observational study

BACKGROUND Earlier work on adults undergoing surgery with cardiopulmonary bypass suggests that there is a close relationship between the lower limit of the cerebral and renal autoregulation pressures. Although cerebral autoregulation during bypass in infants has been extensively investigated, the impact of bypass on kidney function is not well known. It is, nevertheless, acknowledged that the main pathophysiological process involved in cardiac surgery-related kidney damage is tubular injury, and that urine neutrophil gelatinase-associated lipocaline (uNGAL) is a reliable biomarker of injury. OBJECTIVE To identify the most predictive bypass variable for the measurement of renal injury, its threshold value and the most predictive time below that threshold. DESIGN Observational study linking electronically recorded bypass perfusion pressure and oxygen delivery rate with intra-operative uNGAL excretion. Variations in bypass variables were accounted for by their excursions below several thresholds. SETTING French tertiary referral paediatric cardiac centre. PATIENTS A total of 72 infants in whom uNGAL was measured within 1 h of bypass. INTERVENTIONS None. MAIN OUTCOME MEASURE Renal injury, identified by a high creatinine normalised uNGAL concentration (>21.2 μg mmol−1). RESULTS At the end of bypass, 43.75% of infants had high uNGAL. A more than 40% pressure drop below the normal age-standardised mean arterial pressure was associated with high uNGAL. Receiver operating curve [interquartile range] areas were 0.626 [0.501 to 0.752] for a more than 40% drop, and 0.679 [0.555 to 0.804] for a more than 50% drop. A more than 40% pressure drop for 19.5 min provided a 0.65 negative predictive value for high uNGAL, and a more than 50% pressure drop for 5.4 min provided a 0.67 negative predictive value. The link between uNGAL and oxygen delivery rate was negligible. CONCLUSION Maintaining the perfusion pressure above 60% of the normal age-standardised mean arterial pressure may provide an effective renal protective strategy. TRIAL REGISTRATION Registered on October 11, 2010, ClinicalTrials.gov Identifier: NCT01219998. Correspondence to Mirela Bojan, MD, PhD, Department of Anaesthesiology and Critical Care, Necker-Enfants Malades University Hospital, Assistance Publique – Hôpitaux de Paris, 149, rue de Sèvres, 75743 Paris, France Tel: +33 171396663; e-mail: mirela.bojan@nck.aphp.fr © 2018 European Society of Anaesthesiology

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