Exercise-induced plasma volume expansion and post-exercise parasympathetic reactivation

The purpose of this study was to investigate the effect of exercise-induced plasma volume expansion on post-exercise parasympathetic reactivation. Before (D₀) and 2 days after (D₊₂) a supramaximal exercise session, 11 men (21.4 ± 2.6 years and BMI = 23.0 ± 1.4) performed 6-min of submaximal running where heart rate (HR) recovery (HRR) and HR variability (HRV) indices were calculated during the first 10 min of recovery. Relative plasma volume changes (∆PV) were calculated using changes in hematocrit and hemoglobin measured over consecutive mornings from D₀ to D₊₂. Parasympathetic reactivation was evaluated through HRR and vagal-related indexes calculated during a stationary period of recovery. Compared with D₀, ∆PV (+4.8%, P < 0.01) and all vagal-related HRV indices were significantly higher at D₊₂ (all P < 0.05). HRR was not different between trials. Changes in HRV indices, but not HRR, were related to ∆PV (all P < 0.01). HRR and HRV indices characterize distinct independent aspects of cardiac parasympathetic function, with HRV indices being more sensitive to changes in plasma volume than HRR.     

Determinants of the variability of heart rate measures during a competitive period in young soccer players

Measurements of exercise heart rate (HR_ex), HR recovery (HRR) and HR variability (HRV) are used as indices of training status. However, the day-to-day variability of these indices throughout a competitive soccer period is unknown. On 14 occasions during a 3-week competition camp, 18 under 15 (U15) and 15 under 17 (U17) years soccer players performed a 5-min submaximal run, followed by a seated 5-min recovery period. HR_ex was determined during the last 30 s of exercise, while HRR and HRV were measured during the first and last 3 min of the post-exercise recovery period, respectively. U15 players displayed greater HR_ex (P = 0.02) and HRR (P = 0.004) compared with the U17 players, but there was no difference in HRV (P = 0.74). The mean coefficient of variation (CV) for HR_ex was lower than that for HRV [3.4 (90% CL, 3.1, 3.7) vs. 10.7 (9.6, 11.9)%, P < 0.001]; both were lower than that for HRR [13.3 (12.2, 14.3)%, P < 0.01]. In contrast to HR_ex and HRR, the CV for HRV was correlated to maximal aerobic speed (r = −0.52, P = 0.002). There was no correlation between total activity time (training sessions + matches) and CV of any of the quantified variables. The variability of each of these measures and player fitness levels should be considered when interpreting changes in training status.     

Monitoring endurance running performance using cardiac parasympathetic function

The aims of the present study were to (1) assess relationships between running performance and parasympathetic function both at rest and following exercise, and (2) examine changes in heart rate (HR)-derived indices throughout an 8-week period training program in runners. In 14 moderately trained runners (36 ± 7 years), resting vagal-related HR variability (HRV) indices were measured daily, while exercise HR and post-exercise HR recovery (HRR) and HRV indices were measured fortnightly. Maximal aerobic speed (MAS) and 10 km running performance were assessed before and after the training intervention. Correlations (r > 0.60, P < 0.01) were observed between changes in vagal-related indices and changes in MAS and 10 km running time. Exercise HR decreased progressively during the training period (P < 0.01). In the 11 subjects who lowered their 10 km running time >0.5% (responders), resting vagal-related indices showed a progressively increasing trend (time effect P = 0.03) and qualitative indications of possibly and likely higher values during week 7 [+7% (90% CI −3.7;17.0)] and week 9 [+10% (90% CI −1.5;23)] compared with pre-training values, respectively. Post-exercise HRV showed similar changes, despite less pronounced between-group differences. HRR showed a relatively early possible decrease at week 3 [−20% (90% CI −42;10)], with only slight reductions near the end of the program. The results illustrate the potential of resting, exercise and post-exercise HR measurements for both assessing and predicting the impact of aerobic training on endurance running performance.     

Monitoring changes in physical performance with heart rate measures in young soccer players

The aim of the present study was to verify the validity of using exercise heart rate (HRex), HR recovery (HRR) and post-exercise HR variability (HRV) during and after a submaximal running test to predict changes in physical performance over an entire competitive season in highly trained young soccer players. Sixty-five complete data sets were analyzed comparing two consecutive testing sessions (3–4 months apart) collected on 46 players (age 15.1 ± 1.5 years). Physical performance tests included a 5-min run at 9 km h⁻¹ followed by a seated 5-min recovery period to measure HRex, HRR and HRV, a counter movement jump, acceleration and maximal sprinting speed obtained during a 40-m sprint with 10-m splits, repeated-sprint performance and an incremental running test to estimate maximal cardiorespiratory function (end test velocity V _Vam-Eval). Possible changes in physical performance were examined for the players presenting a substantial change in HR measures over two consecutive testing sessions (greater than 3, 13 and 10% for HRex, HRR and HRV, respectively). A decrease in HRex or increase in HRV was associated with likely improvements in V _Vam-Eval; opposite changes led to unclear changes in V _Vam-Eval. Moderate relationships were also found between individual changes in HRR and sprint [r = 0.39, 90% CL (0.07;0.64)] and repeated-sprint performance [r = −0.38 (−0.05;−0.64)]. To conclude, while monitoring HRex and HRV was effective in tracking improvements in V _Vam-Eval, changes in HRR were moderately associated with changes in (repeated-)sprint performance. The present data also question the use of HRex and HRV as systematic markers of physical performance decrements in youth soccer players.     

Effect of cold water immersion on 100-m sprint performance in well-trained swimmers

The aim of the present study was to examine the effect of cold water immersion (CWI) on sprint swimming performance in simulated competition conditions. Ten well-trained swimmers (5 males, 5 females; 19.0 ± 3.9 years) performed two 100-m swimming sprints (S1 and S2) interspersed with a 30-min passive recovery period, during which athletes were randomly assigned to 5 min of CWI (14°C) or an out-of-water control condition (CON 28°C). During tests, sprint times, heart rate (HR), pre- and post-race parasympathetic activity via HR variability (natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal R–R intervals; Ln rMSSD) and blood lactate accumulation ([La]_ac) and clearance ([La]_cle) were recorded. Rates of perceived recovery (RPR) and exertion (RPE) were evaluated before and after each sprint. CWI was associated with a ‘likely’ decrease in swimming performance [1.8% (90% CI 0.2, 3.5)], as well as ‘likely’ lower peak HR [−1.9% (−3.6, −0.2)]. CWI was also associated with a ‘likely’ smaller decrease in Ln rMSSD after the first sprint [−16.7% (−30.9, −4.1)]. RPR was ‘likely’ better [+27.2% (−3.7, 68.0)] following CWI. ‘unclear’ effects were observed for [La]_ac [+24.7% (−13.4, 79.5)], [La]_cle [−7.6% (−24.2, 12.7)] or RPE [+2.0% (−12.3, 18.5)]. Following CWI, changes in sprint times were ‘largely’ correlated with changes in peak HR (r = 0.80). Despite a subjective perception of improved recovery following CWI, this recovery intervention resulted in slower swimming times in well-trained athletes swimming in simulated competition conditions.     

The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R–R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R–R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; −12% (−18; −5)]) and CWT [−11% (−19; −2)]. Leg soreness was almost certainly lower following CWI [−22% (−30; −14)] and CWT [−27% (−37; −15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD_Post-interv) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (−0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD_Post-interv and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD_Post-interv and leg soreness [r = −0.50 (−0.66; −0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies.     

Consecutive days of cold water immersion: effects on cycling performance and heart rate variability

We investigated performance and heart rate (HR) variability (HRV) over consecutive days of cycling with post-exercise cold water immersion (CWI) or passive recovery (PAS). In a crossover design, 11 cyclists completed two separate 3-day training blocks (120 min cycling per day, 66 maximal sprints, 9 min time trialling [TT]), followed by 2 days of recovery-based training. The cyclists recovered from each training session by standing in cold water (10 °C) or at room temperature (27 °C) for 5 min. Mean power for sprints, total TT work and HR were assessed during each session. Resting vagal-HRV (natural logarithm of square-root of mean squared differences of successive R–R intervals; ln rMSSD) was assessed after exercise, after the recovery intervention, during sleep and upon waking. CWI allowed better maintenance of mean sprint power (between-trial difference [90 % confidence limits] +12.4 % [5.9; 18.9]), cadence (+2.0 % [0.6; 3.5]), and mean HR during exercise (+1.6 % [0.0; 3.2]) compared with PAS. ln rMSSD immediately following CWI was higher (+144 % [92; 211]) compared with PAS. There was no difference between the trials in TT performance (?0.2 % [?3.5; 3.0]) or waking ln rMSSD (?1.2 % [?5.9; 3.4]). CWI helps to maintain sprint performance during consecutive days of training, whereas its effects on vagal-HRV vary over time and depend on prior exercise intensity.     

Ultra short-term heart rate recovery after maximal exercise in continuous versus intermittent endurance athletes

This study tested the hypothesis that athletes participating in intermittent sports would exhibit a faster heart rate recovery (HRR) during the initial phase (<30 s) following maximal exercise than athletes participating in continuous endurance sports. Forty-six male athletes were allocated into continuous (CNT, n = 24) or intermittent groups (INT, n = 22), matched for age and aerobic fitness. Athletes performed maximal exercise on a treadmill using the ramp protocol. Immediately upon exercise cessation, subjects were placed supine with continuous measurement of HR during the first minute of recovery. Data were analyzed in 10-s intervals and compared between the groups. Repeated measures ANOVA showed a group × time interaction effects (p ≤ 0.01) for HRR expressed in both beats min⁻¹ and in percentage of peak post-exercise HR (% HR_peak). The INT group had lower HR than CNT group at 10 s (189 vs. 192 beats min⁻¹, p = 0.04; and 96.3 vs. 97.9% HR_peak, p = 0.009) and 20 s (184 vs. 188 beats min⁻¹, p = 0.049; and 93.6 vs. 95.7% HR_peak, p = 0.021) intervals of recovery. The results suggest that athletes engaged in intermittent sports are likely to have faster HRR during the first 20 s after maximal exercise than their counterparts trained for continuous performance.     

Heart rate variability is related to training load variables in interval running exercises

Overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs and/or body. However, there is no “golden standard” for TL measurement. The aim of the present study was to investigate if post-exercise heart rate variability (HRV) could be used to evaluate TL of interval running exercises with different intensities and durations. Thirteen endurance-trained men (35 ± 5 years) performed MO₂₅₀ [moderate intensity, 2 × 6 × 250 m/rec 30 s/5 min at 85% of the maximal velocity of the graded maximal test (V _max)], MO₅₀₀ (2 × 3 × 500 m/rec 1 min/5 min at 85% V _max) and HI₂₅₀ (high intensity, 2 × 6 × 250 m/rec 30 s/5 min at 105% V _max) interval exercises on a treadmill. HRV was analyzed during rest, exercise and immediate 15 min recovery. Fast recovery of LFP (P < 0.001), HFP (P < 0.01) and TP (P < 0.01) occurred during the first two recovery minutes after each exercise. Strong negative correlations (P < 0.01) were found between post-exercise HRV and perceived exertion as well as excess post-exercise oxygen consumption. Post-exercise HRV differentiated interval exercises of equal work, but varying intensity or distance of running bout. The results of the present study suggest that immediate post-exercise HRV may offer objective information on TL of interval exercises with different bout durations and intensities.     

Effect of body posture on postexercise parasympathetic reactivation in men

The aim of the present study was to assess the influence of body posture on post-submaximal exercise parasympathetic reactivation and to examine whether this influence was preserved under a heightened sympathetic background. On four occasions, eleven moderately trained subjects (22.1 ± 3.0 years old) performed, in random order, two consecutive submaximal running bouts (CTs), each followed by 5 min passive recovery in an upright (Up), sitting (Sit), supine (Sup) or supine with legs up position (SupLu). Between both CTs, participants performed 150 s of supramaximal intermittent running (SI). Parasympathetic reactivation was assessed from heart rate recovery (HRR) and variability (HRV; e.g. rMSSD_{30 s}) indices calculated during the 5 min recovery periods [i.e. before (N) and after SI (post-SI)]. In the N condition, Sup position was associated with a faster and greater increase in rMSSD_{30 s} than Sit and SupLu (both P < 0.01), which were all higher compared with Up ( P < 0.001). A 'time' effect was shown in Sit, Sup and SupLu (all P < 0.05), but not in Up ( P = 0.99). All N values were higher than post-SI values ( P < 0.001), except for Up, where a trend was apparent ( P = 0.06). In the post-SI condition, a position effect was preserved for HRR ( P < 0.001), but not for HRV indices ( P = 0.99 for rMSSD_{30 s}). In conclusion, the supine position accelerated and increased parasympathetic reactivation more than the other three positions, but the posture effect was less evident following supramaximal exercise. In the context of an accentuated sympathetic background (i.e. post-SI), postexercise HRV indices are less gravity dependent than HRR, reflecting more the exercise-related changes in parasympathetic activity.     

Can HRV be used to evaluate training load in constant load exercises?

The overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs, and/or body. However, there is no “golden standard” for TL measurement. The aim of this study was to examine if any post-exercise heart rate variability (HRV) indices could be used to evaluate TL in exercises with different intensities and durations. Thirteen endurance-trained males (35 ± 5 year) performed MODE (moderate intensity, 3 km at 60% of the maximal velocity of the graded maximal test (vVO_2max)), HI (high intensity, 3 km at 85% vVO_2max), and PRO (prolonged, 14 km at 60% vVO_2max) exercises on a treadmill. HRV was analyzed with short-time Fourier-transform method during rest, exercise, and 15-min recovery. Rating of perceived exertion (RPE), blood lactate (BLa), and HFP₁₂₀ (mean of 0–120 s post-exercise) described TL of these exercises similarly, being different for HI (P < 0.05) and PRO (P < 0.05) when compared with MODE. RPE and BLa also correlated negatively with HFP₁₂₀ (r = −0.604, −0.401), LFP₁₂₀ (−0.634, −0.601), and TP₁₂₀ (−0.691, −0.569). HRV recovery dynamics were similar after each exercise, but the level of HRV was lower after HI than MODE. Increased intensity or duration of exercise decreased immediate HRV recovery, suggesting that post-exercise HRV may enable an objective evaluation of TL in field conditions. The first 2-min recovery seems to give enough information on HRV recovery for evaluating TL.     

Effect of hypobaric hypoxia on heart rate variability during exercise: a pilot field study

The influence of hypoxia on heart rate variability (HRV) has been studied under resting conditions with mixed results. Differences have been found in physiological responses to normobaric versus hypobaric hypoxia. Our aim was to study the influence of hypobaric hypoxia on HRV during physical exercise to determine whether HRV changes due to the exercise-induced heart rate (HR) increase or whether hypoxia itself exerts an influence. We tested nine healthy non-acclimatised white males (age = 43 ± 7 years) at 400 and 4,200 m during exercises. At 400 m HRV was measured at 50% and 75% maximal oxygen uptake (VO₂ max). At 4,200 m HR was kept equal as during exercise at 400 m by adjusting the intensity of step testing. The Poincaré plot as a non-linear method of HRV analysis was used, where the shape of the ellipse depending on HRV is expressed by two parameters, SD1 and SD2 (correlating to parasympathetic activity and both sympathetic and parasympathetic activity, respectively). We established a decrease in SD2 and an insignificant decrease in SD1 at medium HR at 4,200 m compared to 400 m. Both parameters showed similar tendencies during high-intensity exercise. Our results indicate that hypobaric hypoxia itself exerts an influence on HRV at a moderate HR.     

Favorable Effect of Cytomegalovirus Reactivation on Outcomes in Cord Blood Transplant and Its Differences Among Disease Risk or Type

The effects of cytomegalovirus (CMV) reactivation on cord blood transplant (CBT) are unclear. We assessed the effect of CMV reactivation in adult single-unit CBT without in vivo T cell depletion. Of 3147 eligible cases, 2052 were acute myeloid leukemia (AML), 643 acute lymphoblastic leukemia (ALL), and 452 myelodysplastic syndrome (MDS). CMV reactivation up to 100 days after CBT was associated with better overall survival (OS) compared with no reactivation cases (57.3% versus 52.6% at 3 years after CBT), whereas nonrelapse mortality (NRM) was increased in ALL (16.2% versus 8.9%) and standard disease risk (17.1% versus 10.6%, P = .014) by CMV reactivation. On multivariate analysis, CMV reactivation had favorable effects on relapse in MDS (hazard ratio [HR], .55; P = .044) and high disease risk (HR, .77; P = .047). In NRM, only standard-risk cases showed adverse effects of CMV reactivation (HR, 1.56; P = .026). OS was significantly improved with CMV reactivation in a subgroup of patients with AML (HR, .84; P = .044), MDS (HR, .68; P = .048), and high disease risk (HR, .81; P = .013). This favorable effect of CMV reactivation on OS in AML and high disease risk cases was maintained even after considering the effect of grades II to IV acute graft-versus-host disease. Thus, CMV reactivation might have beneficial or adverse effects on relapse, NRM, and OS, depending on the disease type or disease risk.     

Effects on blood pressure and autonomic nervous system function of a 12-week exercise or exercise plus DASH-diet intervention in individuals with elevated blood pressure

Aim: Hypertension is related to abnormalities in autonomic nervous system (ANS) function, with increased sympathetic output and decreased parasympathetic tone. Lifestyle interventions are the first line of treatment in hypertension, and decreased blood pressure (BP) effects may be related to changes in ANS function. Using heart rate recovery (HRR) from exercise as an index of parasympathetic tone and plasma noradrenaline as an index of sympathetic tone, we investigated the effects of lifestyle interventions on ANS function in patients with elevated BP. Methods: Sedentary participants with elevated BP were randomly assigned to either an exercise only (N = 25), exercise plus dietary approaches to stop hypertension (DASH) diet (N = 12), or waitlist control (N = 15) 12‐week intervention. Plasma noradrenaline was measured at rest and participants performed a peak exercise test before and after the intervention. HRR was calculated as peak heart rate (HR) minus HR at 1 min post‐exercise. Results: Heart rate recovery showed a significant group by time interaction; both intervention groups showed increases in HRR from pre‐ to post‐intervention, while waitlist showed no change. Similarly, both exercise plus diet and exercise groups, but not waitlist, showed significant reductions in BP from pre‐ to post‐intervention. Linear regression revealed that BP post‐intervention was significantly predicted by change in HRR when controlling for pre‐BP, age, gender and BMI. Conclusions: Lifestyle interventions induced training‐reduced BP and altered autonomic tone, indexed by HRR. This study indicates the importance of behavioural modification in hypertension and that increased parasympathetic function is associated with success in reduction of BP.     

The effect of endurance training on resting heart rate variability in sedentary adult males

Eleven previously sedentary adult males, serving as the experimental (EXP) group [mean (SE) age 36.6 (1.7) years, body mass 87.2 (4.3) kg, body mass index, BMI, 28.4 (1.5) kg·m^–2] participated in a 16-week supervised exercise program (3 days·week^–1, 30 min·day^–1, at ≅80% of heart rate reserve) to determine the temporal effects of a moderate-to-vigorous-intensity exercise program on heart rate variability (HRV). Five sedentary males [mean (SD) age 36.6 (4.2 )years, body mass 83.8 (6.6) kg, BMI 22.8 (1.7) kg·m^–2] served as non-exercising controls (CON). HRV was measured every 4 weeks from a resting electrocardiogram obtained while subjects paced their breathing at 10 breaths·min^–1 (0.167 Hz). The time-domain measures of HRV recorded were the proportion of adjacent intervals differing by more than 50 ms (pNN50), the root mean square of successive differences (rMSSD), and the standard deviation of the resting interbeat interval. The frequency-domain measures recorded were high (HF) and low (LF) frequency oscillations, as determined using the fast Fourier transform technique. Aerobic capacity (i.e., peak oxygen uptake) increased by 13.8% in EXP (P<0.001), but did not change in CON. Resting heart rate did not change in either EXP or CON. In EXP, pNN50 at week 12 (P<0.01), rMSSD at weeks 12 (P<0.01) and 16 (P=0.05), and HF power at weeks 12 (P<0.01) and 16 (P=0.05) were elevated above baseline. Time- and frequency-domain measures of HRV remained unchanged in CON. It is concluded that a moderate-to-vigorous-intensity exercise program produces increases in time- and frequency-domain measures of HRV within 12 weeks. Electronic Publication     

Enhanced inflammation with high carbohydrate intake during recovery from eccentric exercise

Inflammation associated with adipose tissue is modulated by macronutrient availability. For example, glucose increases inflammation in obese but not lean individuals. Little is known about how macronutrient intake influences inflammation associated with muscle. The aim of this study was to determine the impact of macronutrient intake differences during recovery from eccentric exercise on the inflammatory response. The study was a cross-over design in which young men and women (n = 12) completed high and low carbohydrate (CHO) conditions. Both conditions consisted of six sets of ten maximal high-force eccentric contractions of the elbow flexors and extensors followed by a controlled diet for the first 8 h post-exercise. Glucose, insulin, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and C-reactive protein were measured from blood samples pre-exercise, 1.5, 4, 8, and 24 h post-exercise. Perceived muscle soreness, strength loss, and serum CK activity were measured through 120 h post-exercise. Perceived soreness was elevated (P < 0.001) at all time points post-exercise in both conditions and was higher (P < 0.05) in the high compared to the low CHO condition. IL-1β increased (P = 0.05) 24 h post-exercise in the high compared to the low CHO condition. There was a trend (P = 0.06) for IL-6 to be elevated in the high compared to the low CHO condition. We conclude that inflammation induced by high-force eccentric exercise in skeletal muscle is greater when a high CHO compared to a low CHO diet is consumed during recovery.     

Changes in heart rate recovery after high-intensity training in well-trained cyclists

Heart rate recovery (HRR) after submaximal exercise improves after training. However, it is unknown if this also occurs in already well-trained cyclists. Therefore, 14 well-trained cyclists (VO_2max 60.3 ± 7.2 ml kg⁻¹ min⁻¹; relative peak power output 5.2 ± 0.6 W kg⁻¹) participated in a high-intensity training programme (eight sessions in 4 weeks). Before and after high-intensity training, performance was assessed with a peak power output test including respiratory gas analysis (VO_2max) and a 40-km time trial. HRR was measured after every high-intensity training session and 40-km time trial. After the training period peak power output, expressed as W kg⁻¹, improved by 4.7% (P = 0.000010) and 40-km time trial improved by 2.2% (P = 0.000007), whereas there was no change in VO_2max (P = 0.066571). Both HRR after the high intensity training sessions (7 ± 6 beats; P = 0.001302) and HRR after the 40-km time trials (6 ± 3 beats; P = 0.023101) improved significantly after the training period. Good relationships were found between improvements in HRR_40-km and improvements in peak power output (r = 0.73; P < 0.0001) and 40-km time trial time (r = 0.96; P < 0.0001). In conclusion, HRR is a sensitive marker which tracks changes in training status in already well-trained cyclists and has the potential to have an important role in monitoring and prescribing training.     

Muscle activity of the core during bilateral,unilateral, seated and standing resistance exercise

Little is known about the effect of performing common resistance exercises standing compared to seated and unilaterally compared to bilaterally on muscle activation of the core. Thus, the purpose of this study was to compare the electromyographic activity (EMG) of the superficial core muscles (i.e. rectus abdominis, external oblique and erector spinae) between seated, standing, bilateral and unilateral dumbbell shoulder presses. 15 healthy males performed five repetitions at 80% of one-repetition maximum of the exercises in randomized order. Results were analyzed with a two-way analysis of variance and a Bonferroni post hoc test. The position × exercise interaction was significantly different for rectus abdominis (P = 0.016), but not for external oblique (P = 0.100) and erector spinae (P = 0.151). The following EMG results were observed: For rectus abdominis: ~49% lower in seated bilateral versus unilateral (P < 0.001), similar in standing bilateral versus unilateral (P = 0.408), ~81% lower in bilateral seated versus standing (P < 0.001), ~59% lower in unilateral seated versus standing (P < 0.001); For external oblique: ~81% lower in seated bilateral versus unilateral (P < 0.001), ~68% lower in standing bilateral than unilateral (P < 0.001), ~58% lower in bilateral seated versus standing (P < 0.001), ~28% lower in unilateral seated versus standing (P = 0.002); For erector spinae: similar in seated bilateral versus unilateral (P = 0.737), ~18% lower in standing bilateral versus unilateral (P = 0.001), similar in seated versus standing bilateral (P = 0.480) and unilateral (P = 0.690). In conclusion, to enhance neuromuscular activation of the superficial core muscles, standing exercises should be used instead of seated exercises, and unilateral exercises should be used instead of bilateral exercises.     

Short term effects of various water immersions on recovery from exhaustive intermittent exercise

In order to investigate the effectiveness of different techniques of water immersion recovery on maximal strength, power and the post-exercise inflammatory response in elite athletes, 41 highly trained (Football, Rugby, Volleyball) male subjects (age = 21.5 ± 4.6 years, mass = 73.1 ± 9.7 kg and height = 176.7 ± 9.7 cm) performed 20 min of exhaustive, intermittent exercise followed by a 15 min recovery intervention. The recovery intervention consisted of different water immersion techniques, including: temperate water immersion (36°C; TWI), cold water immersion (10°C; CWI), contrast water temperature (10–42°C; CWT) and a passive recovery (PAS). Performances during a maximal 30-s rowing test (P_30 s), a maximal vertical counter-movement jump (CMJ) and a maximal isometric voluntary contraction (MVC) of the knee extensor muscles were measured at rest (Pre-exercise), immediately after the exercise (Post-exercise), 1 h after (Post 1 h) and 24 h later (Post 24 h). Leukocyte profile and venous blood markers of muscle damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) were also measured Pre-exercise, Post 1 h and Post 24 h. A significant time effect was observed to indicate a reduction in performance (Pre-exercise vs. Post-exercise) following the exercise bout in all conditions (P < 0.05). Indeed, at 1 h post exercise, a significant improvement in MVC and P_30 s was respectively observed in the CWI and CWT groups compared to pre-exercise. Further, for the CWI group, this result was associated with a comparative blunting of the rise in total number of leucocytes at 1 h post and of plasma concentration of CK at 24 h post. The results indicate that the practice of cold water immersion and contrast water therapy are more effective immersion modalities to promote a faster acute recovery of maximal anaerobic performances (MVC and 30″ all-out respectively) after an intermittent exhaustive exercise. These results may be explained by the suppression of plasma concentrations of markers of inflammation and damage, suggesting reduced passive leakage from disrupted skeletal muscle, which may result in the increase in force production during ensuing bouts of exercise.     

Impact of Anti-CMV IgG Titers and CD34 Count Prior to Hematopoietic Stem Cell Transplantation from Alternative Donors on CMV reactivation

Cytomegalovirus (CMV) reactivation remains one of the main infectious complications following hematopoietic stem cell transplantation (HSCT). In this study, we explored the role of anti-CMV antibody titers in HSCT from alternative donors and to compare the risk of CMV reactivation between posttransplant cyclophosphamide-based haploidentical HSCT and antithymocyte globulin-based unrelated donor (URD) HSCT. We included 98 CMV-positive patients, 30 undergoing haploidentical HSCT and 68 undergoing URD HSCT. The majority of patients had a malignant disease (84%), received a myeloablative conditioning regimen (78%), and received a bone marrow graft (90%). The median pretransplantation anti-CMV IgG level was 109 U/mL. With median follow-up of 2.2 years, a total of 72 CMV reactivations occurred in 50 patients. There was no difference in CMV reactivation pattern between haploidentical HSCT recipients and URD HSCT recipients. In multivariable analysis until the first event, the incidence of CMV reactivation was higher in patients with anti-CMV IgG levels >100 U/mL (hazard ratio [HR], 2.38; P = .005) and in patients diagnosed with grade II-IV acute graft-versus-host disease (GVHD) (HR, 10.8; P = .003) after day +50 and lower in patients who received higher doses of CD34 cells (HR, .44; P = .006). In multivariable analysis for recurring events, the incidence of CMV reactivation was higher in patients receiving reduced-intensity conditioning (HR, 1.69: P = .04) and in patients with acute GVHD (HR, 1.88; P = .02), and lower in those who received higher doses of CD34 cells (HR, .55; P = .01). In summary, we have shown that pretransplantation anti-CMV IgG titers are correlated with CMV reactivation risk. More studies are needed to assess how this information can be incorporated in HSCT. The use of high-dose cellular grafts, a modifiable risk factor, also protects against CMV reactivation.