Charge variants of proposed biosimilar to Omalizumab: Isolation, purification and analysis by HPLC methods.

Omalizumab (Xolair) is a humanized monoclonal antibody derived by recombinant DNA technology. It binds specifically to immunoglobulin E (IgE) which plays a major role in allergic reaction by releasing histamine and other inflammatory factors from mast cells. Omalizumab binds circulatory IgE with high affinity and prevents from its binding to mast cell receptor. Charge variants are one of the critical quality attributes (CQAs) in biological drug development and sources of heterogeneity which needs to be considered in biosimilarity assessment. In this study, biosimilar product of Xolair was expressed in mammalian cell culture process in laboratory to isolate charge variants (acidic, main peak and basic). Different charge variants were isolated from intermediate purified biosimilar product of Xolair. Isolated charge variants were purified with preparative cation exchange chromatography technique and characterized with different analytical tools includes size exclusion chromatography (SEC-HPLC) and cation exchange chromatography (CEX-HPLC). Purity of acidic, main peak and basic variants was 99.58%, 99.98% and 98.64% respectively as per SEC-HPLC and according to CEX-HPLC purity was 94.25%, 95.58% and 91.33% respectively. The study data indicates that isolated charge variants were purified with desired purity and can be further used for process characterization, in vitro potency and in vivo kinetics studies.

[False positive results or what's the probability that a significant P-value indicates a true effect?] / Les résultats faux positifs ou quelle est la probabilité que le traitement soit efficace quand p < 0,05 ?

The use of statistical test is central in the clinical trial. At the statistical level, obtaining a P<0.05 allows to claim the effectiveness of the new studied treatment. However, given its underlying mathematical logic the concept of "P value" is often misinterpreted. It is often assimilated, mistakenly, to the likelihood that treatment is ineffective. Actually the "P value" gives an indirect information about the plausibility of the existence of treatment effect. With "P<0.05", the probability that the treatment is effective may vary depending on other statistical parameters which are the alpha level of risk, the power of the study and especially the a priori probability of the existence of treatment effect. A "P<0.05" does not always produce the same degree of certainty. Thus there exist situations where the risk of a result "P<0.05" is in reality a false positive is very high. This is the case if the power is low, if there is an inflation of the alpha risk or if the result is exploratory or chance discoveries. This possibility is important to take into consideration when interpreting the results of clinical trials in order to avoid pushing ahead significant results in appearance, but which are likely to be actually false positive results.

Comparison of refractive outcomes obtained with two swept-source OCT-based optical biometers after cataract surgery: A study of 152 eyes.

PURPOSE: To compare two swept-source OCT optical biometers, the Anterion® (Heidelberg Engineering GmbH, Heidelberg, Germany) and the IOLMaster 700® (Carl Zeiss Meditec AG, Jena, Germany), in the analysis of biometric data, intraocular lens (IOL) calculation and postoperative spherical equivalent predictability. METHODS: This was a real-life, single-center, retrospective study including 152 eyes of 81 consecutive patients referred for cataract surgery. All patients were examined with the IOLMaster 700® and the Anterion®. Biometric data (axial length [AL], anterior chamber depth [ACD], mean keratometry [Km], K1 [flat keratometry], K2 [steep keratometry] and axis, TK1 [flat total keratometry], TK2 [steep total keratometry], central pachymetry, lens thickness [LT], white-to-white distance [WTW]), IOL calculation with the SRK/T formula, and postoperative refractive outcome at 1 month were compared. RESULTS: All biometric measurements were significantly different between the two biometers. Correlations were excellent for AL, pachymetry, ACD, LT and keratometry measurements, and for the IOL calculation (r>0.96, intraclass correlation coefficient=1). The IOL power for emmetropia was similar between both biometers when the SRK/T formula was used (20.84±3.24D versus 20.86±3.29D, P=0.61). The mean postoperative spherical equivalent prediction error calculated using the SRK/T formula was 0.03±0.5D for the IOLMaster 700® versus 0.01±0.47D for the Anterion® (P=0.12). CONCLUSIONS: This study showed excellent correlation and agreement for the biometric measurements and the IOL power calculation with the SRK/T formula between both biometers.

Comparison of the accuracy of nine intraocular lens power calculation formulas using partial coherence interferometry.

Cataract surgery is the most performed procedure in the world. To achieve the target refraction, several intraocular lens (IOL) power calculation formulas have been developed to improve the accuracy of IOL power predictions. We compared the accuracy of 9 IOL power calculation formulas (SRK/T, Hoffer Q, Holladay 1, Haigis, Barrett Universal II, Kane, EVO 2.0, Ladas Super formula and Hill-RBF 3.0) using partial coherence interferometry (PCI). We collected data from patients who underwent uncomplicated cataract surgery with implantation of 1 of 3 IOL types currently used in our center. All preoperative biometric measurements were performed using PCI. Prediction errors (PE) were deduced from refractive outcomes evaluated 3 months after surgery. The mean prediction error (ME), mean absolute prediction error (MAE), median absolute prediction error (MedAE), and standard deviation of prediction error (SD) were calculated, as well as the percentage of eyes with a PE within ± 0.25, ± 0.50, ± 0.75 and ± 1.00D for each formula. We included 126 eyes of 126 patients. Kane achieved the lowest MAE and SD across the entire sample as well as the highest percentage of PE within ± 0.50D and was shown to be more accurate than Haigis and Hoffer Q (P<001). For an axial length of more than 26.0mm, EVO 2.0 and Barrett obtained the lowest MAEs, with EVO 2.0 and Kane showing a higher percentage of prediction at ±0.50D compared to old generation formulas except for SRK/T (P=04). All investigated formulas achieved good results; there was a tendency toward better outcomes with new generation formulas, especially in atypical eyes.

Twenty-one days of spirulina supplementation lowers heart rate during submaximal cycling and augments power output during repeated sprints in trained cyclists.

Spirulina supplementation has been reported to improve time to exhaustion and maximal oxygen consumption (V̇O2max). However, there is limited information on its influence over the multiple intensities experienced by cyclists during training and competition. Fifteen trained males (age 40 ± 8 years, V̇O2max 51.14 ± 6.43 mL/min/kg) ingested 6 g/day of spirulina or placebo for 21 days in a double-blinded randomised crossover design, with a 14-day washout period between trials. Participants completed a 1-hour submaximal endurance test at 55% external power output max and a 16.1-km time trial (day 1), followed by a lactate threshold test and repeated sprint performance tests (RSPTs) (day 2). Heart rate (bpm), respiratory exchange ratio, oxygen consumption (mL/min/kg), lactate and glucose (mmol/L), time (seconds), power output (W), and hemoglobin (g/L) were compared across conditions. Following spirulina supplementation, lactate and heart rate were significantly lower (P < 0.05) during submaximal endurance tests (2.05 ± 0.80 mmol/L vs 2.39 ± 0.89 mmol/L and 139 ± 11 bpm vs 144 ± 12 bpm), hemoglobin was significantly higher (152.6 ± 9.0 g/L) than placebo (143.2 ± 8.5 g/L), and peak and average power were significantly higher during RSPTs (968 ± 177 W vs 929 ± 149 W and 770 ± 117 W vs 738 ± 86 W). No differences existed between conditions for all oxygen consumption values, 16.1-km time trial measures, and lactate threshold tests (P > 0.05). Spirulina supplementation reduces homeostatic disturbances during submaximal exercise and augments power output during RSPTs. Novelty: Spirulina supplementation lowers heart rate and blood lactate during ∼1-hour submaximal cycling. Spirulina supplementation elicits significant augmentations in hemoglobin and power outputs during RSPTs.

The role of posterior corneal power in 21st century biometry: A review.

PURPOSE: Intraocular lens (IOL) calculation and biometry have evolved significantly in recent decades. However, present outcomes are still suboptimal. Our objective is to summarize the results reported in the literature with regard to a new variable, the value of the relationship between anterior and posterior corneal curvature in the biometric calculation of IOL power. METHODS: We have created a narrative revision of the existing evidence regarding the posterior to anterior corneal curvature ratio in IOL calculation. RESULTS: The corneal posterior/anterior ratio (P/A ratio), also called Gullstrand ratio, has a standard deviation of 2.4% in normal people, hence causing a possible IOL power miscalculation error of up to 0.75 diopters (D). This error is magnified in pathological corneas or in those with previous refractive surgery. Including the P/A ratio in the IOL formula reduces errors in the calculation of IOL power. CONCLUSIONS: Measurement of the posterior corneal surface should be recommended prior to IOL calculation, given the demonstrated results regarding the P/A ratio for IOL power calculation. Regarding toric IOL calculation, we suggest incorporation of all internal astigmatic vectors, for instance, posterior corneal surface, IOL tilt induced toricity, and retinal astigmatism. All of these factors may improve surgical outcomes.

Intramuscular hyaluronic acid expression following repetitive power training induced nonfunctional overreaching.

Hyaluronic acid (HA) contributes to extracellular matrix viscosity and fiber regeneration. HA role in resistance training (RT) performance adaptations is unclear. RT men performed power training (nonfunctional overreaching (NFOR) or normal training (CG)) over 7.5 days. Post RT, the CG improved power while NFOR did not with HA content decreasing 34.5% in NFOR with no change in CG. HA is critical for muscular recovery; decreased HA may contribute to impaired power adaptations with NFOR RT. Novelty: Nonfunctional over-reaching decreases muscular hyaluronic acid.

Critical skating intensity on a slide board: physiological and neuromuscular responses and correlation with performance on ice.

The aim of this study was to assess the physiological and neuromuscular responses at critical skating intensity on a slide board and to investigate the correlations between critical cadence (CC) and skating performances on ice. Thirteen well-trained speed skaters (age,19.8 ± 4.2 years; weight, 69.6 ± 9.06 kg) performed a maximal skating incremental test (IT) on a slide board. CC was determined from 3 to 4 trials to exhaustion lasting from 3.1 ± 0.7 to 13.9 ± 3.1 min, using linear and hyperbolic mathematical fittings. A time to exhaustion test at CC (TTE-CC) was performed. CC values (55.3 ± 5.0 ppm) were significantly higher than cadence at the respiratory compensation point (RCP) (53.5 ± 4.0 ppm). Mean duration of TTE-CC was 22.9 ± 4.8 min. Peak values of oxygen uptake, heart rate (HR), ventilation, respiratory exchange ratio (RER), and ratings of perceived exertion (RPE) during TTE-CC were significantly lower (p < 0.05) than the peak values reached during the IT. Oxygen uptake, HR, ventilation, RER, and RPE significantly increased from 25% to 100% of TTE-CC. Muscle activity (integrated electromyography) significantly increased after 75% of TTE-CC for vastus lateralis and gluteus maximus muscles. Oxygen uptake at CC was better associated to skating performance on 500, 1000, 1500, and 5000 m than peak oxygen uptake at IT and oxygen uptake at RCP. Physiological responses indicate that critical skating intensity on slide board occurred within the heavy exercise domain where oxygen uptake increases but does not reach its maximum. Critical cadence could be used as a better indicator of performance and training prescription for long track speed skating distances.

Mild dehydration impaired intermittent sprint performance and thermoregulation in females.

The effects of mild dehydration during ice hockey are well-studied in males but not females. In a randomized, crossover design, 11 female varsity hockey players drank no fluid (1.7% ± 0.3% body mass loss) or water to maintain hydration during simulated-hockey exercise. Core temperature (P < 0.01) and perceived fatigue (P = 0.02) were higher and sprint power lower (P < 0.01) when mildly dehydrated. Thus, mild dehydration may impair hockey performance and thermoregulation while increasing perceived fatigue in females. Novelty Female stop-and-go sport athletes may benefit their in-game sprint performance and thermoregulation by following personalized in-game hydration to prevent becoming mildly dehydrated.

Influence of sex gap on muscle strength and functional mobility in patients with cystic fibrosis.

The objectives of this study were to determine whether there were differences in handgrip strength and functional mobility between patients with cystic fibrosis (CF) and healthy controls with regard to sex and to ascertain whether these differences were related to lung function. Thirty-eight patients with CF (21 women) and 38 healthy controls aged 18-65 years were included. Muscle weakness and functional mobility were assessed through handgrip strength; walking speed; and time, velocity, and power derived from a single sit-to-stand (STS) test. Patients with CF showed differences for STS variables and walking speed but not for handgrip strength, compared with healthy controls. Considering sex differences, female patients showed differences for all variables analyzed while males with CF only exhibited differences for STS variables, compared with healthy controls. Females with CF showed moderate relationship between muscle weakness, functional mobility, and lung function (|r| = 0.45-0.49; p ≤ 0.05) whereas no relationships were observed for males with CF. The influence of chronic infection with Pseudomonas aeruginosa and pancreatic insufficiency on muscle weakness and functional mobility was similar in both sexes. Differences in muscle strength and functional mobility were predominantly observed in females with CF. These results suggest an important effect of sex gap on muscle weakness and functional mobility in patients with CF. Novelty The influence of sex gap on muscle weakness in CF has been shown. Muscle weakness was predominantly observed in females with CF.

Is active recovery during cold water immersion better than active or passive recovery in thermoneutral water for postrecovery high-intensity sprint interval performance?

High-intensity exercise is impaired by increased esophageal temperature (Tes) above 38 °C and/or decreased muscle temperature. We compared the effects of three 30-min recovery strategies following a first set of three 30-s Wingate tests (set 1), on a similar postrecovery set of Wingate tests (set 2). Recovery conditions were passive recovery in thermoneutral (34 °C) water (Passive-TN) and active recovery (underwater cycling; ∼33% maximum power) in thermoneutral (Active-TN) or cold (15 °C) water (Active-C). Tes rose for all conditions by the end of set 1 (∼1.0 °C). After recovery, Tes returned to baseline in both Active-C and Passive-TN but remained elevated in Active-TN (p < 0.05). At the end of set 2, Tes was lower in Active-C (37.2 °C) than both Passive-TN (38.1 °C) and Active-TN (38.8 °C) (p < 0.05). From set 1 to 2 mean power did not change with Passive-TN (+0.2%), increased with Active-TN (+2.4%; p < 0.05), and decreased with Active-C (-3.2%; p < 0.05). Heart rate was similar between conditions throughout, except at end-recovery; it was lower in Passive-TN (92 beats·min-1) than both exercise conditions (Active-TN, 126 beats·min-1; Active-C, 116 beats·min-1) (p < 0.05). Although Active-C significantly reduced Tes, the best postrecovery performance occurred with Active-TN. Novelty An initial set of 3 Wingates increased Tes to ∼38 °C. Thirty minutes of Active-C was well tolerated, and decreased Tes and blood lactate to baseline values, but decreased subsequent Wingate performance.

Heart rate variability and recovery following maximal exercise in endurance athletes and physically active individuals.

The purpose of this study was to determine potential adverse cardiac effects of chronic endurance training by comparing sympathovagal modulation via heart rate variability (HRV) and heart rate recovery (HRR) in middle-aged endurance athletes (EA) and physically active individuals (PA) following maximal exercise. Thirty-six (age, 53 ± 5 years) EA and 19 (age, 56 ± 5 years) PA were recruited to complete a 2-week exercise diary and graded exercise to exhaustion. Time domain and power spectral HRV analyses were completed on recorded R-R intervals. EA had a greater HRR slope following exercise (95% confidence interval, 0.0134-0.0138 vs. 0.0101-0.0104 beats/s; p < 0.001). While EA had greater HRR at 1-5 min after exercise (all p < 0.01), PA and EA did not differ when expressed as a percentage of baseline heart rate (130 ± 19 vs. 139 ± 19; p = 0.2). Root mean square of successive differences in R-R intervals (rest and immediately after exercise) were elevated in EA (p < 0.05). Low-frequency (LF) and high-frequency (HF) spectral components were nonsignificantly elevated after exercise (p = 0.045-0.147) in EA while LF/HF was not different (p = 0.529-0.986). This data suggests greater HRR in EA may arise in part due to a lower resting HR. While nonsignificant elevations in HF and LF in EA produces a LF/HF similar to PA, absolute spectral component modulation differed. These observations require further exploration. Novelty Acute effects of exercise on HRV in EA compared with a relevant control group, PA, are unknown. EA had greater HRR and nonsignificant elevations in LF and HF compared with PA, yet LF/HF was not different. Future work should explore the implications of this observation.

Muscle fiber composition, jumping performance, and rate of force development adaptations induced by different power training volumes in females.

This study aimed to investigate the effect of 3 different eccentric-only power training volumes on muscle fiber type composition and power performance. Twenty-nine females were assigned into 3 groups and performed 10 weeks of either 3 (low volume), 6 (moderate volume), or 9 (high volume) sets/session of 4 fast-velocity eccentric-only half-squats against 70% of concentric 1-repetition maximum (1RM), followed by 3 maximum countermovement jumps (CMJs) after each set. Half-squat 1RM, CMJ height/power, maximum isometric force, rate of force development (RFD) and muscle fiber cross-sectional area (CSA) were increased in all groups (p = 0.001). Low-volume training induced higher increases in CMJ height/power and early RFD, compared with the moderate- and high-volume training programs (p < 0.001). Significant reductions in type IIx muscle fiber percentages and %CSAs were found after moderate- and high-volume training, with concomitant increases in type IIa fibers (p = 0.001). Significant correlations were found between the changes in type IIa and type IIx percentages, fiber CSA, %CSA, and the changes in performance (r: -0.787 to 0.792; p < 0.05). These results suggest that relatively large eccentric power training volumes may result in detrimental neuromuscular adaptations, minimal changes in early RFD, and a reduction of type IIx muscle fiber percentage. Novelty Low but not high volume of power training maintains type IIx muscle fibers. Early rate of force development increases after a low- or moderate-power training volume, but not after a high-power training volume. Training-induced changes in type IIx muscle fiber percentage is related with changes in early rate of force development.

Application of critical intensity model during slide board skating.

Critical cadence (CC), critical power (CP), and the work above CP (W') were determined from linear and hyperbolic modelling during skating on a slide board, in 13 well-trained speed skaters. Three to 4 trials to exhaustion were used for the fitting. CC from the linear model was higher than the hyperbolic model (56.0 ± 4.8 vs 55.0 ± 4.5 push-offs/min, p = 0.01). No differences were found for CP and W' parameters from the models analyzed.

Dominant and nondominant leg press training induce similar contralateral and ipsilateral limb training adaptations with children.

Cross-education has been extensively investigated with adults. Adult studies report asymmetrical cross-education adaptations predominately after dominant limb training. The objective of the study was to examine unilateral leg press (LP) training of the dominant or nondominant leg on contralateral and ipsilateral strength and balance measures. Forty-two youth (10-13 years) were placed (random allocation) into a dominant (n = 15) or nondominant (n = 14) leg press training group or nontraining control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pre-/post-training for ipsilateral and contralateral 1-repetition maximum (RM) horizontal LP, maximum voluntary isometric contraction (MVIC) of knee extensors (KE) and flexors (KF), countermovement jump (CMJ), triple hop test (THT), MVIC strength of elbow flexors (EF) and handgrip, as well as the stork and Y balance tests. Both dominant and nondominant LP training significantly (p < 0.05) increased both ipsilateral and contralateral lower body strength (LP 1RM (dominant: 59.6%-81.8%; nondominant: 59.5%-96.3%), KE MVIC (dominant: 12.4%-18.3%; nondominant: 8.6%-18.6%), KF MVIC (dominant: 7.9%-22.3%; nondominant: nonsignificant-3.8%), and power (CMJ: dominant: 11.1%-18.1%; nondominant: 7.7%-16.6%)). The exception was that nondominant LP training demonstrated a nonsignificant change with the contralateral KF MVIC. Other significant improvements were with nondominant LP training on ipsilateral EF 1RM (6.2%) and THT (9.6%). There were no significant changes with EF and handgrip MVIC. The contralateral leg stork balance test was impaired following dominant LP training. KF MVIC exhibited the only significant relative post-training to pretraining (post-test/pre-test) ratio differences between dominant versus nondominant LP cross-education training effects. In conclusion, children exhibit symmetrical cross-education or global training adaptations with unilateral training of dominant or nondominant upper leg.

Acetaminophen ingestion improves muscle activation and performance during a 3-min all-out cycling test.

Acute acetaminophen (ACT) ingestion has been shown to enhance cycling time-trial performance. The purpose of this study was to assess whether ACT ingestion enhances muscle activation and critical power (CP) during maximal cycling exercise. Sixteen active male participants completed two 3-min all-out tests against a fixed resistance on an electronically braked cycle ergometer 60 min after ingestion of 1 g of ACT or placebo (maltodextrin, PL). CP was estimated as the mean power output over the final 30 s of the test and W' (the curvature constant of the power-duration relationship) was estimated as the work done above CP. The femoral nerve was stimulated every 30 s to measure membrane excitability (M-wave) and surface electromyography (EMGRMS) was recorded continuously to infer muscle activation. Compared with PL, ACT ingestion increased CP (ACT: 297 ± 32 W vs. PL: 288 ± 31 W, P < 0.001) and total work done (ACT: 66.4 ± 6.5 kJ vs. PL: 65.4 ± 6.4 kJ, P = 0.03) without impacting W' (ACT: 13.1 ± 2.9 kJ vs. PL: 13.6 ± 2.4 kJ, P = 0.19) or the M-wave amplitude (P = 0.66) during the 3-min all-out cycling test. Normalised EMGRMS amplitude declined throughout the 3-min protocol in both PL and ACT conditions; however, the decline in EMGRMS amplitude was attenuated in the ACT condition, such that the EMGRMS amplitude was greater in ACT compared with PL over the last 60 s of the test (P = 0.04). These findings indicate that acute ACT ingestion might increase performance and CP during maximal cycling exercise by enhancing muscle activation.

Acute caffeine supplementation promotes small to moderate improvements in performance tests indicative of in-game success in professional female basketball players.

The aim of this study was to determine the effect of acute caffeine supplementation on anaerobic performance in professional female basketball players. A double-blind, placebo-controlled, experimental design was used in a randomized counterbalanced manner. In separate sessions, 10 professional basketball players ingested caffeine (3 mg/kg body mass) or a placebo (dextrose: 3 mg/kg body mass) 60 min before completing countermovement jumps (CMJ) with and without arm swing, a squat jump (SJ), the Lane Agility Drill, 20-m sprints (with 5-m and 10-m split times recorded) with and without dribbling a ball, and a suicide run. Participants provided ratings of perceived exertion (RPE) and ratings of perceived performance 30 min following testing. Data analyses included the use of effect size (ES) and significance. Caffeine supplementation produced small nonsignificant (p > 0.05) increases in CMJ without arm swing (ES = 0.30), CMJ with arm swing (ES = 0.29), SJ (ES = 0.33), and the lane agility drill (ES = -0.27). Caffeine supplementation produced small to moderate significant improvements in 10-m (ES = -0.63; p = 0.05) and 20-m (ES = -0.41; p = 0.04) sprint times without dribbling. Caffeine supplementation promoted a moderate significant reduction in RPE during the test battery (ES = -1.18; p = 0.04) and a small nonsignificant improvement in perceived performance (ES = 0.23; p = 0.53). Acute caffeine supplementation may produce small to moderate improvements in key performance attributes required for basketball while reducing RPE.

Comparison of 2 weekly-equalized volume resistance-training routines using different frequencies on body composition and performance in trained males.

The present study compared the effects of 2 weekly-equalized volume and relative load interventions on body composition, strength, and power. Based on individual baseline maximal strength values, 18 recreationally trained men were pair-matched and consequently randomly assigned to one of the following experimental groups: a low volume per session with a high frequency (LV-HF, n = 9) group who trained for 4 days (Mondays, Tuesdays, Thursdays, and Fridays) or a high volume per session and low frequency (HV-LF, n = 9) group who trained for 2 days (Mondays and Thursdays). Both groups performed 2 different routines over 6 weeks. Participants were tested pre- and post- intervention for maximal strength, upper body power, fat-free mass, limb circumferences, and muscle thickness. Compared with baseline values, both groups increased their fat-free mass (HV-LF: +1.19 ± 1.94; LV-HF: +1.36 ± 1.06 kg, p < 0.05) and vastus medialis thickness (HV-LF: +2.18 ± 1.88, p < 0.01; LV-HF: +1.82 ± 2.43 mm, p < 0.05), but only the HV-LF group enhanced arm circumference (1.08 ± 1.47 cm, p < 0.05) and elbow flexors thickness (2.21 ± 2.81 mm, P < 0.01) values and decreased their fat mass (-2.41 ± 1.10, P < 0.01). Both groups improved (p < 0.01) the maximal loads lifted in the bench press (LV-HF: +0.14 ± 0.01; HV-LF: +0.14 ± 0.01 kg·body mass-1) and the squat (LV-HF: +0.14 ± 0.06; HV-LF: 0.17 ± 0.01 kg·body mass-1) exercises as well as in upper body power (LV-HF: +0.22 ± 0.25; HV-LF: +0.27 ± 0.22 W·body mass-1) Although both training strategies improved performance and lower body muscle mass, only the HV-LF protocol increased upper body hypertrophy and improved body composition.

Evidence of homologous and heterologous effects after unilateral leg training in youth.

The positive effects of unilateral training on contralateral muscles (cross education) has been demonstrated with adults for over a century. There is limited evidence for cross education of heterologous muscles. Cross education has not been demonstrated with children. It was the objective of this study to investigate cross-education training in children examining ipsilateral and contralateral homologous and heterologous muscles. Forty-eight male children (aged 10-13 years) were assessed for unilateral, ipsilateral and contralateral lower limb strength, power and endurance (1-repetition maximum (RM) leg press, knee extensors (KE) and flexors (KF) maximum voluntary isometric contractions (MVIC), countermovement jump, muscle endurance test (leg press repetitions with 60% 1RM)), and upper body unilateral MVIC elbow flexors (EF) and handgrip strength. An 8-week training program involved 2 unilateral leg press resistance-training groups (high load/low repetitions: 4-8 sets of 5RM, and low load/high repetitions: 1-2 sets of 20RM) and control (untrained) group. All muscles exhibited improvements of 6.1% to 89.1%. The trained limb exhibited greater adaptations than the untrained limb for leg press 1RM (40.3% vs. 25.2%; p = 0.005), and 60% 1RM leg press (104.1% vs. 73.4%; p = 0.0001). The high load/low repetition training induced (p < 0.0001) greater improvements than low load/high repetition with KE, KF, EF MVIC and leg press 1RM. This is the first study to demonstrate cross-education effects with children and that the effects of unilateral training involve both contralateral homologous and heterologous muscles with the greatest strength-training responses from high-load/low-repetition training.