Acute effects of dryland muscular endurance and maximum strength training on sprint swimming performance in young swimmers.

The study examined acute effects of dryland muscular endurance (ME) and maximum strength (MS) sessions on performance, physiological, and biomechanical variables during a subsequent sprint swimming session. Twenty-seven swimmers (16.5 ± 2.6 yrs) completed three experimental conditions including: i) ME, 55% of 1-repetition maximum, ii) MS, 90% of 1-repetition maximum, and iii) control (CON, no dry-land). Twenty minutes following ME, MS and CON sessions swimmers performed a 10-s tethered swimming sprint, four by 50-m (4 × 50-m), and a 100-m front crawl sprints. Performance time, blood lactate, heart rate (HR), stroke rate (SR), stroke length (SL), stroke index (SI), and stroke efficiency (ηF) were measured during 4 × 50-m and 100-m. Hand grip strength (HG), and shoulder muscles isometric strength (ISO) were measured after each session. Mean 4 × 50-m time increased in ME compared to CON by 1.7 ± 2.7% (p = 0.01), while 100-m time was similar among conditions (p > 0.05). ISO was lower after dry-land training in all conditions (p = 0.01). Tethered force, HG, HR, SR, SL, SI, and ηF were no different between conditions (p > 0.05). Dryland ME session decrease swimming performance; however, ME and MS sessions did not affect technical ability during a subsequent maximum intensity swimming.

Skeletal muscle fiber composition may modify the effect of nutrition on body composition in young females.

BACKGROUND AND AIM: The aim of this study was to investigate the hypothesis that healthy, normal-weight females with greater proportions and sizes of the oxidative muscle fibers would also be characterized by a healthier body composition compared with individuals with increased glycolytic fibers, even if both follow similar nutritional plans. METHODS AND RESULTS: Vastus lateralis muscle fiber-type composition, body composition through dual-energy X-ray absorptiometry, and dietary intakes through questionnaire were evaluated in twenty-two young, healthy, non-obese females (age: 21.3±1.8yrs, body mass: 67.5±6.2 kg, body height: 1.66±0.05m, body mass index (BMI): 24.2±2.6  kg m-2). The participants were allocated into two groups according to their type I muscle fibers percentage [high (HI) and low (LI)]. The participants of the LI group were characterized by significantly higher body mass, fat mass, BMI, and cross-sectional and percentage cross-sectional area (%CSA) of type IIx muscle fibers compared with participants of the HI group (p < 0.021). In contrast, the HI group was characterized by higher cross-sectional and %CSA of type I muscle fibers compared with the LI group (p < 0.038). Significant correlations were observed between body fat mass, lean body mass, total energy intake, fat energy intake, and %CSAs of type I and IIx muscle fibers (r: -0.505 to 0.685; p < 0.05). CONCLUSION: In conclusion, this study suggests that muscle fiber composition is an important factor that at least partly could explain the observed differential inter-individual responses of the body composition to nutrition in female individuals. Increased %CSAs of type I muscle fibers seem to act as a protective mechanism against obesity and favor a healthier body composition, neutralizing the negative effect of increased caloric fats intake on body composition, probably because of their greater oxidative metabolic properties and fat utilization capacities. In contrast, female individuals with low type I and high type IIx %CSAs of type I seem to be more metabolically inflexible and dietinduced obesity prone, even if they consume fewer total daily calories and fats.

The Effects of Heavy Resisted Sled Pulling on Sprint Mechanics and Spatiotemporal Parameters.

ABSTRACT: Stavridis, I, Ekizos, A, Zisi, M, Agilara, G-O, Tsolakis, C, Terzis, G, and Paradisis, G. The effects of heavy resisted sled pulling on sprint mechanics and spatiotemporal parameters. J Strength Cond Res 37(12): 2346-2353, 2023-This study examines the effects of 2 resisted sled sprinting (RSS) training programs: with a load corresponding to the running velocity associated with the apex of the individual velocity-power relationship (50%vdec), with a load equal to 10% of body mass (10% BM), and of an unresisted sprint training (URS). We measured the 30-m sprint performance in intervals of 5 m examining sprint acceleration, mechanical properties (theoretical maximal horizontal power [Pmax], force [F0], velocity [v0], slope of the force-velocity relationship [SFv], maximal ratio of horizontal-to-resultant force [RFmax], rate of decrease in RF [Drf]), and spatiotemporal parameters (step frequency [SF], step length [SL], flight time [FT], and contact time [CT]). Twenty-seven sprinters were randomly assigned into the 50%vdec, 10% BM, and URS groups, performing 12 sessions over 6 consecutive weeks (2 sets of 5 sprints per session). The 50%vdec group significantly improved (p < 0.05) their performance in all 30-m intervals. Posttraining, the 50%vdec group showed significantly increased Pmax, F0, and RFmax (mean differences: 1.46 ± 1.70 W·kg-1, 0.51 ± 0.68 N·kg-1, and 0.17 ± 0.18%, respectively), compared with pretraining. The 50%vdec group achieved higher SF, whereas FT decreased postintervention. No significant changes (p > 0.05) were found in the performance and mechanical and spatiotemporal variables in the other groups. In conclusion, RSS training with a load of 50%vdec provides an effective loading stimulus to induce adaptations that improve sprint acceleration performance. The improvements are explained by greater amounts of force and power, efficient force application, and higher step frequencies.

Body composition and 6 minute walking ability in late-onset pompe disease patients after 9 years of enzyme replacement therapy.

OBJECTIVE: Pompe disease is a rare autosomal recessive disorder caused by the deficiency of acid α-glycosidase resulting in accumulation of glycogen in the lysosomes. The late-onset form of the disease (LOPD) causes primarily progressive muscle weakness and respiratory insufficiency. Enzyme replacement therapy (ERT) introduced in 2006, showed mild improvement or stabilization of the symptoms although long-term data are limited. Aim of the study was to describe the progression of body composition and walking ability in LOPD patients receiving ERT consistently for 9 years. METHODS: Lean body mass, bone mineral density, body fat and 6 min walking distance were assessed in three male and three female LOPD patients (height 165.8 ± 11.2 cm, age 42.3 ± 11.8yrs, body mass 71.1 ± 20.8 kg, at study entry), every three years, for 9 years since ERT initiation (T0, T3, T6, T9). RESULTS: Total body and upper extremities' lean mass remained unchanged (p < 0.05), but it was decreased for the lower extremities (T3:13.06 ± 3.848 kg vs. T9:11.63 ± 3.49 kg, p < 0.05). Lean body mass was not significantly different after 9 years of ERT compared to before the ERT initiation (T0 to T9). Bone mineral density remained unchanged. Percent body fat increased (T0:39.1 ± 10.3%, vs. T9:43.1 ± 10.4%, p < 0.05). Six minute walking distance tended to increase after 3 years of ERT and decreased gradually thereafter, with no difference between T0-T9. Lean mass of the lower extremities adjusted for body weight was significantly correlated with 6 min walking distance (r = 0.712, p < 0.05). CONCLUSION: The current data show that enzyme replacement therapy may preserve lean body mass, bone mineral density and walking capacity in LOPD patients.

Effects of Complex Vs. Compound Training on Competitive Throwing Performance.

ABSTRACT: Thomas, K, Spyridon, M, Nikolaos, Z, Angeliki-Nikolleta, S, Giorgos, K, Giorgos, G, and Gerasimos, T. Effects of complex vs. compound training on competitive throwing performance. J Strength Cond Res 36(7): 1866-1874, 2022-The purpose of this study was to investigate the effects of complex (CPX; strength and power exercises in pairs) vs. compound (CPD; strength and power exercises in different days) training on competitive track and field throwing performance. Ten well-trained throwers (7 male throwers and 3 female throwers) followed a 34-week periodized training program including 2 preparation periods. During the winter 4-week, precompetition phase, athletes were randomly assigned to CPX or CPD groups, while the opposite assignment was performed during the spring precompetition phase (counterbalanced design). Before and after each training period competitive track and field throwing performance, shot put throws, snatch, squat and bench press 1 repetition maximum (1RM), vertical jumps, rate of force development (RFD), and body composition were evaluated. Competitive track and field throwing performance increased significantly by 5.4 ± 2.9% and 1.9 ± 1.7%, after CPX and CPD, respectively, with a significant difference between groups (p < 0.001). Shot put throws and 1RM strength in bench press increased similarly after both programs (p < 0.05), but vertical jumps increased only after CPX training. CPX induced greater increases in 1RM strength in snatch and squat, RFD, and lean body mass compared with CPD (p < 0.005). The linear combination of training-induced changes in RFD 150ms, 1RM in squat, snatch, and total lean mass explained the 80% of the percentage increase in competitive track and field throwing performance (p = 0.007). These results suggest that 4 weeks of CPX training during the precompetition period induce greater increases in competitive track and field throwing performance, 1RM strength, power, and RFD compared with CPD training.

Preconditioning Strategies Before Maximum Clean Performance in Female Weightlifters.

ABSTRACT: Kelekian, GK, Zaras, N, Stasinaki, AN, Spiliopoulou, P, Karampatsos, G, Bogdanis, G, and Terzis, G. Preconditioning strategies before maximum clean performance in female weightlifters. J Strength Cond Res 36(8): 2318-2321, 2022-The aim of the study was to examine the acute effect of performing clean pulls with either 85% or 120% one repetition maximum (1RM), on subsequent clean performance, in female Olympic weightlifters. Eight competitive female Olympic weightlifters (age, 22.9 ± 5.8 years; height, 1.67 ± 0.06 m; training experience, 6.1 ± 3.9 years; clean performance, 66.3 ± 3.9 kg), performed clean pulls either with 85% or with 120% 1RM, 3 minutes before their maximum effort in clean, in 2 different days, in a counterbalanced order. The rate of perceived exertion (RPE) was provided after each intervention. Body composition (dual x-ray absorptiometry), countermovement jumping (CMJ) performance, leg press isometric rate of force development (RFD), and peak force (PF) were also evaluated on different days. Clean performance was increased by 6.1 ± 3.6% ( p = 0.002) after preconditioning with 85% 1RM and 4.7 ± 3.1% ( p = 0.004) after 120% 1RM. Rate of perceived exertion was lower after preconditioning with 85% 1RM, compared with 120% 1RM ( p = 0.015). No significant correlation was found between the changes in clean performance after 85% or 120% 1RM, with lean body mass, CMJ performance, and isometric leg press RFD, and leg press PF. These data suggest that lifting either 85% or 120% 1RM in clean pulls is an effective strategy for acute increase of clean performance in female Olympic weightlifters, whereas the use of 85% 1RM load may be performed with less exertion.

Effect of exercise training on functional capacity and body composition in myotonic dystrophy type 2 patients.

BACKGROUND: Myotonic dystrophy type 2 (DM2) is a neuromuscular disorder characterized by myotonia and muscle weakness, with no medical treatment to prevent a decline in decline. It is unknown whether exercise training is effective in DM2. The aim of this study was to investigate the effect of exercise training on functional capacity and body composition in these patients. METHODS: Body composition and functional capacity were evaluated at the beginning (T1) and end (T2) of a 12 wk control period, and again after 16 wk of exercise training (T3) in 10 patients. RESULTS: No changes were recorded after the control period. Handgrip strength, 5× sit to stand, timed up and go, 6 min walk distance, lean body mass (LBM), and bone mineral density (BMD) increased while arterial pressure decreased after training. CONCLUSIONS: These results suggest that supervised exercise training improves functional capacity, LBM, and BMD in ambulatory DM2 patients.

Changes in EMG and movement velocity during a set to failure against different loads in the bench press exercise.

This study examined changes in movement velocity and surface electromyographic (sEMG) activity of the pectoralis major (PM) and triceps brachii (TB) muscles during the bench press exercise to failure against different loads. Fourteen men performed a set to failure with maximum intended velocity, against low (40%-1 repetition maximum-RM), moderate (60%-1RM), and heavy loads (80%-1RM). Number of repetitions, volume load, mean and peak velocity, and total time increased with decreasing load (40% > 60% > 80%, p < 0.01). sEMG comparisons between different loads were performed by matching time under tension at the initial, middle, and last part of the set. sEMG was higher in the middle and last repetitions, compared with the initial, for all loads in both muscles (p < 0.001). sEMG activity of both muscles was higher in the 60% and 80%-1RM conditions compared with the 40%1-RM (p < 0.007). Also, sEMG of both muscles was similar for the 60%-1RM and 80%-1RM loads at the initial, middle, and last repetitions, with the exception of the last repetitions for the TB muscle. In contrast, sEMG integrated activity was higher for the 40% 1-RM and 60% 1-RM (p < 0.01) compared with the 80% 1-RM load. Mean velocity loss at exhaustion and drop in sEMG median frequency were greater in the 40% and 60%-1RM compared with the 80%-1RM condition (p < 0.05). It was concluded that performing a set to exhaustion with maximum intended velocity using a load of 60% 1-RM combines the characteristics of the high average sEMG activity of heavier loads, and the high total integrated sEMG observed at lighter loads.

Potentiation of Bench Press Throw Performance Using a Heavy Load and Velocity-Based Repetition Control.

ABSTRACT: Tsoukos, A, Brown, LE, Terzis, G, Veligekas, P, and Bogdanis, GC. Potentiation of bench press throw performance using a heavy load and velocity-based repetition control. J Strength Cond Res 35(2S): S72-S79, 2021-The acute effects of heavy load bench press exercise on subsequent bench press throw (BPT) performance and surface electromyographic (sEMG) activity were examined using movement velocity control. Eleven resistance-trained men completed 3 conditions in randomized and counterbalanced order. In 2 conditions, bench press was performed as fast as possible against a load of 80% of 1 repetition maximum, until mean velocity dropped to 90% (C90) or 70% (C70) of the fastest repetition. In the control condition, no bench press was performed. Single maximal BPT efforts were performed in all conditions after warm-up and throughout the 12 minutes of subsequent recovery. Mean propulsive velocity (MPV), peak velocity (PV), and sEMG activity of the prime mover muscles were measured during the BPT efforts. The total number of repetitions and volume load during bench press were significantly greater in C70 compared with C90 (6.5 ± 1.9 vs. 3.4 ± 0.9 repetitions and 557.8 ± 177.8 vs. 293.8 ± 95.7 kg, p < 0.01). In C90, MPV was increased 5.3-7.4% (p < 0.01) for a prolonged period (4-12 minutes), while in C70, MPV increased only at 10 minutes (+5.9%, p < 0.01) and 12 minutes (+4.3%, p < 0.01). Peak velocity was improved only in the C90 at 8-12th min by 3.6-4.7% (p ≤ 0.05). Surface electromyographic activity of the pectoralis major muscle was significantly greater than baseline at 10 minutes of recovery only in the C90 (p < 0.01). Performance gains may be optimized by taking into account the individual fatigue profiles, allowing a percentage drop of only 10% in movement velocity during the conditioning bench press exercise.

Effects of a 25-Week Periodized Training Macrocycle on Muscle Strength, Power, Muscle Architecture, and Performance in Well-Trained Track and Field Throwers.

ABSTRACT: Anousaki, E, Zaras, N, Stasinaki A-N, Panidi, I, Terzis, T, and Karampatsos, G. Effects of a 25-week periodized training macrocycle on muscle strength, power, muscle architecture, and performance in well-trained track and field throwers. J Strength Cond Res 35(10): 2728-2736, 2021-The purpose of the study was to investigate the effect of a 25-week macrocycle on strength, power, vastus lateralis (VL) muscle architecture, and competitive track and field throwing performance, in well-trained track and field throwers. Twelve well-trained throwers (age: 24.3 ± 5.5 years, mass: 96.6 ± 9.9 kg, and height: 1.82 ± 0.02 m), participated in the study. All athletes followed a 25-week periodized training program divided into 3 training phases: the hypertrophy/maximum strength phase, the maximum strength/power phase, and the power/speed phase. Measurements were performed at the beginning of the training period (T1), after the first training phase (T2), and after the end of the training period (T3). Measurements included the following: competitive track and field throwing performance; shot put throws; maximum strength (1-RM) in snatch, clean, and squat; countermovement jump (CMJ); and VL muscle architecture. Competitive track and field throwing performance and shot put throws increased from T1 to T3 by 10.9 ± 3.2% (p = 0.001) and 5.1 ± 6.4% (P = 0.049), respectively. 1 RM strength in snatch and squat increased significantly from T1 to T3 by 9.7 ± 8.9% (p = 0.001) and 9.9 ± 7.1% (p = 0.002), respectively. Countermovement jump height increased only from T1 to T2 by 10.9 ± 11.8% (p = 0.026). A significant increase was found for VL fascicle length between T1 and T3 (9.6 ± 11.1%, p = 0.049). Strong correlations were found between the percentage increase of competitive track and field throwing performance with 1 RM snatch (r = 0.571, p = 0.046) and with shot put throws (r = 0.715, p = 0.001). Twenty five weeks of training may increase performance and VL fascicle length, whereas increases in 1 RM snatch and in shot put throws are associated with competitive track and field throwing performance in well-trained throwers.

Effect of Concurrent Power Training and High-Intensity Interval Cycling on Muscle Morphology and Performance.

ABSTRACT: Spiliopoulou, P, Zaras, N, Methenitis, S, Papadimas, G, Papadopoulos, C, Bogdanis, GC, and Terzis, G. Effect of concurrent power training and high-intensity interval cycling on muscle morphology and performance. J Strength Cond Res 35(9): 2464-2471, 2021-The aim of the study was to examine the effect of performing high-intensity interval cycling on muscle morphology and performance immediately after power training (PT). Twenty healthy female physical education students were assigned into 2 training groups. One group performed PT, and the other group performed the same PT followed by high-intensity interval aerobic training on a cycle ergometer (PTC). Training was performed 3 days per week for 6 weeks. Countermovement jump (CMJ) height and CMJ power, half-squat maximal strength (1 repetition maximum), maximum aerobic power, vastus lateralis muscle fiber composition, and cross-sectional area (CSA) were evaluated before and after the intervention. Countermovement jump height increased after PT (10.1 ± 6.6%, p = 0.002) but not after PTC (-5.1 ± 10.5%, p = 0.099), with significant difference between groups (p = 0.001). Countermovement jump power increased after PT (4.5 ± 4.9%, p = 0.021) but not after PTC (-2.4 ± 6.4, p = 0.278), with significant difference between groups (p = 0.017). One repetition maximum increased similarly in both groups. Muscle fiber composition was not altered after either PT or PTC. Vastus lateralis muscle fiber CSA increased significantly and similarly after both PT (I: 16.9 ± 16.2%, p = 0.035, ΙΙΑ: 12.7 ± 10.9%, p = 0.008,ΙΙΧ: 15.5 ± 17.1%, p = 0.021) and PTC (Ι: 18.0 ± 23.7%, p = 0.033,ΙΙΑ: 18.2 ± 11.4%, p = 0.001,ΙΙΧ: 25.5 ± 19.6%, p = 0.003). These results suggest that the addition of high-intensity interval cycling to PT inhibits the anticipated increase in jumping performance induced by PT per se. This inhibition is not explained by changes in muscle fiber type composition or vastus lateralis muscle fiber CSA adaptations.

Comparison Between Unilateral and Bilateral Plyometric Training on Single- and Double-Leg Jumping Performance and Strength.

Bogdanis, GC, Tsoukos, A, Kaloheri, O, Terzis, G, Veligekas, P, and Brown, LE. Comparison between unilateral and bilateral plyometric training on single- and double-leg jumping performance and strength. J Strength Cond Res 33(3): 633-640, 2019-This study compared the effects of unilateral and bilateral plyometric training on single- and double-leg jumping performance, maximal strength, and rate of force development (RFD). Fifteen moderately trained subjects were randomly assigned to either a unilateral (U, n = 7) or bilateral group (B, n = 8). Both groups performed maximal effort plyometric leg exercises 2 times per week for 6 weeks. The B group performed all exercises with both legs, whereas the U group performed half the repetitions with each leg, so that total exercise volume was the same. Jumping performance was assessed by countermovement jumps (CMJs) and drop jumps (DJs), whereas maximal isometric leg press strength and RFD were measured before and after training for each leg separately and both legs together. Countermovement jump improvement with both legs was not significantly different between U (12.1 ± 7.2%) and B (11.0 ± 5.5%) groups. However, the sum of right- and left-leg CMJ only improved in the U group (19.0 ± 7.1%, p < 0.001) and was unchanged in the B group (3.4 ± 8.4%, p = 0.80). Maximal isometric leg press force with both legs was increased similarly between groups (B: 20.1 ± 6.5%, U: 19.9 ± 6.2%). However, the sum of right- and left-leg maximal force increased more in U compared with B group (23.8 ± 9.1% vs. 11.9 ± 6.2%, p = 0.009, respectively). Similarly, the sum of right- and left-leg RFD0-50 and RFD0-100 were improved only in the U group (34-36%, p < 0.01). Unilateral plyometric training was more effective at increasing both single- and double-leg jumping performance, isometric leg press maximal force, and RFD when compared with bilateral training.

Fiber Type Composition and Rate of Force Development in Endurance- and Resistance-Trained Individuals.

Methenitis, S, Spengos, K, Zaras, N, Stasinaki, A-N, Papadimas, G, Karampatsos, G, Arnaoutis, G, and Terzis, G. Fiber type composition and rate of force development in endurance- and resistance-trained individuals. J Strength Cond Res 33(9): 2388-2397, 2019-The purpose of the study was to investigate the relationship between muscle fiber composition and the rate of force development (RFD) in well-trained individuals with different training background. Thirty-eight young men with different training background participated: 9 endurance runners, 10 power-trained individuals, 9 strength-trained individuals, and 10 sedentary individuals. They performed maximal isometric leg press for the measurement of RFD. Body composition (dual x-ray absorptiometry) and vastus lateralis fiber type composition were also evaluated. When all participants were examined as a group, moderate correlations were found between the percent of type II muscle fibers and RFD between 100 and 600 milliseconds (r = 0.321-0.497; p ≤ 0.05). The correlation coefficients were higher for the cross-sectional area (CSA) and the %CSA of type II and IIx muscle fibers (r = 0.599-0.847; p < 0.001). For the power group, RFD up to 250 milliseconds highly correlated with % type IIx muscle fibers and type IIx fiber CSA (r = 0.670-0.826; p ≤ 0.05), as well as with %CSA of type IIx fibers (r = 0.714-0.975; p ≤ 0.05). Significant correlations were found between the relative RFD (·kg lower extremities lean mass) and CSA-%CSA of type II and IIx fibers for the power group (r = 0.676-0.903; p ≤ 0.05). No significant correlations were found between muscle morphology and RFD for the other groups. In conclusion, the present data suggest that there is a strong link between the type IIx muscle fibers and early RFD and relative RFD in power-trained participants. Type II fibers seem to be moderately linked with RFD in non-power-trained individuals.

High-intensity Interval Training Frequency: Cardiometabolic Effects and Quality of Life.

The effects of high intensity interval training (HIIT) frequency on cardiometabolic health and quality of life were examined in 35 healthy inactive adults (age: 31.7±2.6 yrs, VO2peak: 32.7±7.4 ml·: kg-1 ·: min-1). Participants were randomly assigned to a control (CON) and two training groups, which performed 10×60-s cycling at ~83% of peak power, two (HIIT-2) or three times per week (HIIT-3) for eight weeks. Compared with CON, both training regimes resulted in similar improvements in VO2peak (HIIT-2: 10.8%, p=0.048, HIIT-3: 13.6%, p=0.017), waist circumference (HIIT-2: -1.4 cm, p=0.048, HIIT-3: -2.4 cm, p=0.028), thigh cross-sectional area (HIIT-2: 11.4 cm2, p=0.001, HIIT-3: 9.3 cm2, p=0.001) and the physical health component of quality of life (HIIT-2: 8.4, p=0.001, HIIT-3: 12.2, p=0.001). However, HIIT-3 conferred additional health-related benefits by reducing total body and trunk fat percentage (p<0.05, compared with CON), total cholesterol and low-density lipoprotein-cholesterol (p<0.02, compared with CON) and by improving the mental component of quality of life (p=0.045, compared with CON). In conclusion, performing HIIT only twice per week is effective in promoting cardiometabolic health-related adaptations and quality of life in inactive adults. However, higher HIIT frequency is required for an effect on fat deposits, cholesterol and mental component of well-being.

Delayed Effects of a Low-Volume, Power-Type Resistance Exercise Session on Explosive Performance.

Tsoukos, A, Veligekas, P, Brown, LE, Terzis, G, and Bogdanis, GC. Delayed effects of a low-volume, power-type resistance exercise session on explosive performance. J Strength Cond Res 32(3): 643-650, 2018-This study examined the delayed effects of a power-type training session on explosive performance. Seventeen well-trained male power and team sport athletes (age: 22.7 ± 5.5 years, height: 181 ± 8 cm, body mass: 80.7 ± 8.6 kg, body fat: 9.2 ± 1.7%, 1 repetition maximum (1RM) half-squat: 163 ± 29 kg) performed 4 sessions (2 experimental and 2 control) 1 week apart in a randomized and counterbalanced order. Explosive performance was assessed before, 24 and 48 hours after a low-volume, power-type training session (5 × 4 jump squats at 40% 1RM with 3 minutes rest), as well as before and after 24 and 48 hours of rest (control). Dependent variables were as follows: countermovement jump (CMJ), reactive strength index (RSI) during a drop jump, leg press maximum isometric force, and rate of force development (RFD) at 3 time windows: 0-100, 0-200, and 0-300 milliseconds. Analysis of variance revealed no changes in the control conditions. In contrast after training, CMJ was improved by 5.1 ± 1.0% and 3.0 ± 1.0% at 24 and 48 hours, respectively, compared with baseline. The RSI improved by 10.7 ± 2.1% only at 24 hours. The RFD increased at all time windows at 24 hours (range of improvement: 9.7 ± 3.4% to 18.3 ± 4.1%, p < 0.01). However, at 48 hours, improvement was only seen in RFD0-100 (9.8 ± 3.1%, p < 0.01). These findings suggest that a low-volume, power-type training session results in delayed enhancement of explosive muscle performance, which is greatest at 24 hours after the activity. Athletes are advised to perform power-type training 1 day before competition or a high-quality training session to improve their performances.

The Effect of Short-Term Sport-Specific Strength and Conditioning Training on Physical Fitness of Well-Trained Mixed Martial Arts Athletes.

The purpose of the present study was to investigate the effect of a short-term, high-intensity, low-volume Mixed Martial Arts (MMA) specific strength and conditioning training program on performance in national level MMA athletes. Seventeen experienced fighters were divided into two groups: (A) Specific Training Group (STG; n = 10), which followed a specific strength and conditioning program designed according to the demands of MMA competition and (B) Regular Training Group (RTG; n = 7), in which participants followed a regular strength and conditioning program commonly used by MMA athletes. Before and after the four-week training period (3 days per week), body composition, aerobic fitness, strength, power and speed were evaluated. Significant improvements in estimated VO2max, average power during the 2000 m rowing, bench press, back squat and deadlift 1RM, SJ power, CMJ height power, medicine ball throw velocity, 10 m sprint and 2 m take down speed and fat-free mass were found only in the STG (3.7 to 22.2%; p < 0.05; Hedge's g = -0.42 - 4.1). No significant changes were found for the RTG (p = 0.225 to 0.811). Significant differences between the groups were found for almost all post-training assessments (p < 0.05; Hedge's g = 0.25 - 1.45) as well as for the percentage changes from pre to post training (p < 0.05; Hedge's g: 0.25 - 1.45). Significant relationships were found between percentage changes in fat-free mass, endurance capacity, muscle strength/power and speed (r: -0.475 to 0.758; p < 0.05). These results suggest that a high-intensity low-volume strength and conditioning training intervention designed according to the demands of MMA competition may result in significant performance improvements for well-trained fighters.

Protein ingestion preserves proteasome activity during intense aseptic inflammation and facilitates skeletal muscle recovery in humans.

The ubiquitin-proteasome system (UPS) is the main cellular proteolytic system responsible for the degradation of normal and abnormal (e.g. oxidised) proteins. Under catabolic conditions characterised by chronic inflammation, the UPS is activated resulting in proteolysis, muscle wasting and impaired muscle function. Milk proteins provide sulphur-containing amino acid and have been proposed to affect muscle inflammation. However, the response of the UPS to aseptic inflammation and protein supplementation is largely unknown. The aim of this study was to investigate how milk protein supplementation affects UPS activity and skeletal muscle function under conditions of aseptic injury induced by intense, eccentric exercise. In a double-blind, cross-over, repeated measures design, eleven men received either placebo (PLA) or milk protein concentrate (PRO, 4×20 g on exercise day and 20 g/d for the following 8 days), following an acute bout of eccentric exercise (twenty sets of fifteen eccentric contractions at 30°/s) on an isokinetic dynamometer. In each trial, muscle biopsies were obtained from the vastus lateralis muscle at baseline, as well as at 2 and 8 d post exercise, whereas blood samples were collected before exercise and at 6 h, 1 d, 2 d and 8 d post exercise. Muscle strength and soreness were assessed before exercise, 6 h post exercise and then daily for 8 consecutive days. PRO preserved chymotrypsin-like activity and attenuated the decrease of strength, facilitating its recovery. PRO also prevented the increase of NF-κB phosphorylation and HSP70 expression throughout recovery. We conclude that milk PRO supplementation following exercise-induced muscle trauma preserves proteasome activity and attenuates strength decline during the pro-inflammatory phase.

Acute Effect of Countermovement Jumping on Throwing Performance in Track and Field Athletes During Competition.

Karampatsos, GP, Korfiatis, PG, Zaras, ND, Georgiadis, GV, and Terzis, GD. Acute effect of countermovement jumping on throwing performance in track and field athletes during competition. J Strength Cond Res 32(1): 359-364, 2017-The purpose of the study was to investigate whether performing 3 consecutive countermovement jumps (CMJs) just before an attempt enhances performance in track and field throwers during competition. Twelve shot putters, 8 hammer throwers, 9 discus throwers, and 3 javelin throwers of both sexes participated in the study. They performed 3 maximal CMJs 85 ± 12 seconds before the second, fourth, and sixth attempt during 3 different official competitions of national level. Maximal strength (1 repetition maximum [1RM]) in squat and bench press was measured 1 week after the competition. Mean throwing performance was significantly higher after the CMJs intervention (2.66 ± 4.3%, range of increase 0.02-18.98%, p = 0.0001). Similarly, maximum throwing performance was significantly higher after the CMJs (2.76 ± 3.29%, range of increase 0.09-13.93%, p = 0.0009). All but 2 athletes increased their best performance after the CMJs. The percentage increase in performance was similar between sexes (male athletes 2.56 ± 3.01%; female athletes 3.06 ± 3.76%, p = 0.677), but it was higher for the "lighter throws" (discus and javelin throw: 4.66 ± 4.11%) compared with the "heavier throws" (shot and hammer throw: 1.62 ± 2.04%, p = 0.008). The percentage increase in performance was not significantly correlated with 1RM squat or bench press, anthropometric characteristics, and personal best performance. These results suggest that performing 3 CMJs approximately 1 minute before an attempt may increase track and field throwing performance during competition.

The Acute Impact of Different Types of Aerobic Exercise on Arterial Wave Reflections and Inflammation.

OBJECTIVES: Whilst physical activity is linked to cardiovascular health, it has lately been recognized that different types of exercise exert diverse effects on the cardiovascular system. Therefore, we investigated the acute effects of continuous moderate-intensity aerobic exercise (CAE) and high-intensity interval aerobic exercise (hIAE) on arterial function and inflammation. METHODS: Twenty healthy men (mean age 22.6 ± 3.3 years) were recruited in this crossover study. Each of the 20 volunteers participated in two separate sessions (hIAE and CAE). The augmentation index (AIx) of aortic pressure waveforms and serum levels of interleukin-17 (IL-17) were measured before and after each exercise session. RESULTS: There were no significant differences in baseline hemodynamic and inflammatory measurements before CAE and hIAE. Compared to baseline, AIx was significantly improved after CAE (p = 0.04), while there was no significant change after hIAE (p = 0.65). Serum levels of IL-17 were significantly elevated after CAE (p = 0.042), while hIAE had no significant effect on IL-17 levels (p = 0.47). Interestingly, there was an inverse association between the elevation of IL-17 levels and the AIx improvement after CAE (p = 0.05). CONCLUSION: These findings provide additional evidence concerning the cardiovascular effects of different types of exercise training through modification of peripheral hemodynamics and the inflammatory process.

Early phase interference between low-intensity running and power training in moderately trained females.

PURPOSE: The aim of the study was to investigate the effects of low-intensity running performed immediately after lower-body power-training sessions on power development. METHODS: Twenty young females participated in 6 weeks, 3/week, of either lower body power training (PT) or lower body power training followed by 30 min of low-intensity running (PET) eliciting 60-70 % of maximal heart rate. The following were measured before and after the training period: counter-movement jump, isometric leg press force and rate of force development (RFD), half squat 1-RM, vastus lateralis fiber type composition and cross sectional area, resting intramuscular fiber conduction velocity (MFCV), and heart rate during the modified Bruce treadmill test. RESULTS: Counter-movement jump height and peak power increased after PT (10.7 ± 6.2 and 12.9 ± 18.7 %, p < 0.05) but not after PET (3.4 ± 7.6 and 5.11 ± 10.94 %, p > 0.05). Maximum isometric force, RFD, and half squat 1-RM increased similarly in both groups. Muscle fiber type composition was not altered in either group. Muscle fiber cross sectional area increased only after PT (17.5 ± 17.4, 14.5 ± 10.4, 20.36 ± 11.3 %, in type I, IIA, and IIX fibers, respectively, p < 0.05). Likewise, mean MFCV increased with PT only (before: 4.53 ± 0.38 m s(-1), after: 5.09 ± 0.39 m s(-1), p = 0.027). Submaximal heart rate during the Bruce treadmill test remained unchanged after PT but decreased after PET. CONCLUSION: These results suggest that low-intensity running performed after lower-body power training impairs the exercise-induced adaptation in stretch-shortening cycle jumping performance (vertical jump height, peak power), during the first 6 weeks of training, which may be partially linked to inhibited muscle fiber hypertrophy and muscle fiber conduction velocity.