Explosive Strength Performance Research Articles

The Effects of Different Stretching Techniques Used in Warm-Up on the Triggering of Post-Activation Performance Enhancement in Soccer Players

The aim of this research was to investigate the effects of different stretching techniques used during warm-up exercises prior to post-activation performance enhancement (PAPE) on the explosive lower extremity strength performance of soccer players. This cross-sectional study involved the participation of 13 male soccer players with an average age of 22.38 ± 1.75, body height of 174.38 ± 3.94, and body mass of 72.30 ± 4.13. To determine the participants’ maximal strength performance, one repeated maximal strength (1-RM) squat exercise was applied. The PAPE protocol was then implemented with a squat exercise consisting of three repetitions at 80% of 1-RM. The warm-up protocols consisted of 5 min of cycling, followed by dynamic stretching, static stretching, or proprioceptive neuromuscular facilitation (PNF) stretching exercises. These protocols were applied on four different days with a 72 h interval. A vertical jump test was conducted to measure the participants’ explosive strength performance. The research data were analyzed using IBM Statistics (SPSS version 26.0, Armonk, NY, USA) software. The findings of this study revealed statistically significant differences in vertical jump performance values after PAPE among participants based on the different stretching techniques used during warm-up (p = 0.00). In this context, the research concluded that dynamic stretching is the optimal stretching technique during warm-up exercises before PAPE to maximize its effects. On the other hand, static stretching was found to negatively affect performance by absorbing the PAPE effect.

Acute Effects of Combined Lower-Body High-Intensity Interval Training and Upper-Body Strength Exercise on Explosive Strength Performance in Naturally Menstruating Women.

We aimed at investigating the acute effects of lower-body high-intensity interval training (HIIT) on upper- and lower-body explosive strength assessed by mean propulsive velocity (MPV) in naturally menstruating women. In addition, we assessed the combination of lower-body HIIT and squat, as well as lower-body HIIT and bench press, on bench press and squat MPV. Thirteen women (age: 23 [2]y, menstrual cycle length: 28.4 [2.0]d) completed 2 training modalities on separate days (separated by 30 [4.2]d) consisting of HIIT followed by lower-body (HIIT + LBS) or upper-body (HIIT + UBS) strength loading. Squat and bench press MPV were assessed before HIIT (T0), after HIIT (T1), after the strength loading (T2), and 24hours postloading (T3). Mixed factorial analysis of variance indicated a significant effect for time in bench press and squat (P < .001) but not for interaction. Pairwise comparison showed that bench press MPV remained unchanged (P = 1.000) at T1 but was reduced at T2 compared with T0 (HIIT + LBS: -8.2% [3.9%], HIIT + UBS: -13.8% [12.1%], P < .001) and T1 (HIIT + LBS: -7.1% [3.2%], HIIT + UBS: -12.7% [8.7%], P < .001). Squat MPV decreased at T1 (HIIT + LBS: -6.0% [8.8%], HIIT + UBS: -4.8% [5.4%], P = .009) and was found to be decreased at T2 compared with T0 in both conditions (HIIT + LBS: -6.9% [3.3%], HIIT + UBS: -7.4% [6.1%], P < .001) but not compared with T1 (P = 1.000). Bench press and squat MPV returned to baseline at T3 compared with T0 (P > .050). Lower- but not upper-body explosive strength was reduced by HIIT. HIIT combined with upper- or lower-body strength loading resulted in a reduction of squat and bench press explosive strength.

Can the high intensity interval running in slope affect concurrently explosive strength performance?

Background: Physical exercise programs are typically composed of activities directed to the development of different physical abilities, usually stimulated in the same session. Objective: The aim of the study was to determine the effect of one session of aerobic exercise at high intensity to 1% and 10% gradient on the height (HJump) and kinematics of the depth jump (PExc - eccentric, concentric phase PCon, and contact time – CT). Methods: Twenty-five moderately trained men (VO2Max 53.2 ± 4.3 mL.kg-1.min-1) attended five visits in the laboratory. Familiarity with the procedures in depth jump, VO2Max measures and their velocity associated (VVO2Max), and time to exhaustion performance (TLim) were performed at two initial visits. Results: On the three subsequent visits, the volunteers were subjected to three maximum depth jumps before and 10 min after the following conditions: (1) running intervals at high intensity of 10% gradient (R10%), (2) at 1% gradient (R1%), and control condition (CON). The order of conditions was determined randomly. A running condition did not induce significant changes from HJump (R1% 1.1% vs 1.0% R10%) when expressed as percentage difference from the CON condition. The PExc, PCon, and CT also did not change after running sessions (P&gt; 0.05). None of the intervals running strategies were able to generate significant change in height and kinematics of the vertical depth jump. Conclusion: The prescription of the running at VVO2Max in 1% or 10% gradient does not seem to lead to concurrent effect, is suggested to ensure the concomitant development of maximal aerobic power and explosive strength.

The Effect of Plyometric Training on the Speed, Agility, and Explosive Strength Performance in Elite Athletes

The purpose of this study was to evaluate the speed, agility, and explosive strength performance of elite basketball players over an 8-week plyometric training program. Fifteen elite male college basketball players in Taiwan (average age 22.16 ± 0.85 years old) were publicly recruited. All participants received 24 plyometric training courses three times per week for 8 weeks, and the courses were implemented pre- and post-test. The speed and agility test items were divided into a 20 m sprint and a T-shaped run. In the explosive strength test, a force plate was used to measure countermovement jump to understand the pre- and post-test differences in all the test indicators, including the rate of force development, time of the rate of force development, ground reaction forces for the moment of jumping, duration of passage, and jump height. It was found that, after the participants underwent the plyometric training program, the body mass index and body fat percentage were significantly reduced, the skeletal muscle mass was significantly increased, and the post-test scores for speed and agility improved significantly. All the participants exhibited a steeper gradient for the rate of force development (r = −0.816~−0.963) and a shorter time for the rate of force development (0.107~0.232 s). The ground reaction forces reached 1509.61~2387.11 Newtons. The duration of passage reached 0.643 s, and the jump height reached 0.624 m. The conclusion was that the plyometric training program can increase muscle volume in the lower limbs and legs, increase the rate of force development, and shorten the jumping time, thereby enhancing explosive strength.

TREINO DE FORTALECIMENTO DO CORE NO CONDICIONAMENTO FÍSICO DE JOGADORES DE FUTEBOL UNIVERSITÁRIOS

ABSTRACT Introduction: The concept of CORE emerged in mechanical-neurological studies of rehabilitation in the 80s, referring to the central muscles of the human trunk, including the lumbar-pelvis-abdominal-perineal-hip complex responsible for the body orthostatic stability and support. Strengthening the CORE has received increasing attention from sports medicine specialists after the 2000s, and strength training is the subject of recent research in competitive sports. However, there is still a lack of conceptual studies of protocols for training focused on soccer athletes. Objective: Verify a CORE strength training protocol based on the analysis of the CORE training concept, its main functions, and introductory practical examples. Methods: Literature data collection, experimental and statistical-mathematical methods, and theoretical analysis about CORE training focused on explosive strength performance in soccer players are used. The developed protocol experiments with 44 athletes, divided into experimental and control groups, by sex. Information is collected on goal shooting, 30-meter pass, balance, stability, and symmetry. Results: The group experienced better results in both sexes(P&lt;0.05). Conclusion: The explosion strength indicators of the players were significantly improved. Whether male or female athletes, the higher the skill level, the stronger the CORE stability in players. Therefore, the CORE stability and strengthening in athletes promote a benefit in the technical level of soccer players. Evidence Level II; Therapeutic Studies - Investigating the result.

Acute Effects of Concurrent High-Intensity Interval Cycling and Bench-Press Loading on Upper- and Lower-Body Explosive Strength Performance.

This study examined the acute effects of lower-body high-intensity interval loading (HIIT) on explosive upper- and lower-body strength, as well as the combined effect of HIIT and bench-press loading versus HIIT and squat loading on the explosive upper- and lower-body strength. Fifteen physically active men completed 2 sessions consisting of HIIT (4 × 4min cycling at 80% of peak power output) immediately followed by lower- (HIIT + LBS) or upper-body (HIIT + UBS) strength loading (3 × 5 + 3 × 3 repetitions at 80% 1-repetition maximum [ie,6 sets in total]) in a randomized order. Squat and bench-press mean propulsive velocity (MPV) was assessed before HIIT (T0), immediately after HIIT (T1), immediately after the strength loading (T2), and 24hours after the experimental session (T3). Squat MPV decreased to a similar magnitude at T1 in HIIT + LBS (-5.3% [7.6%], P = .117, g = .597) and HIIT + UBS (-5.7% [6.9%], P = .016, g = .484), while bench press remained unchanged (-1.4% [4.7%], P = 1.000, g = .152, and -1.0% [7.0%], P = 1.000, g = .113, respectively). Both squat and bench-press MPV were statistically reduced at T2 compared to T0 (HIIT + LBS: -7.5% [7.8%], P = .016, g = .847, and -6.8% [4.6%], P < .001, g = .724; HIIT + UBS: -3.9% [3.8%], P = .007, g = .359, and -15.5% [6.7%], P < .001, d = 1.879). Bench-press MPV at T2 was significantly lower in HIIT + UBS when compared to HIIT + LBS (P = .002, d = 1.219). These findings indicate lower- but not upper-body explosive strength to be acutely reduced by preceding lower-body HIIT. However, lower-body HIIT combined with either upper- or lower-body strength loading resulted in a similar acute reduction of both squat and bench-press explosive strength.

Acute Effects of Post-Activation Potentiation on Explosive Strength Performance in Wrestling Athletes

Background: Researching methods of improving athlete performance has always been a topical issue. When the studies conducted in this context are examined, many different applications and methods of improving sportive performance have been tested. Especially Post-Activation Potential (PAP) is a very popular subject, and the lack of consensus among researchers on how long the rest period will be after PAP application makes this subject worth investigating. Aim: The aim of this research is to determine the most appropriate resting time interval to produce the highest explosive power after the PAP protocol. Methods: The mean age of the participants group of the research was 19,31±1,21, their height was 170,31±3,42, their weight was 69,09±4,06 and their maximal squat one repetition performance (1-RM) was 86,36±5,60. In this research, measurements were completed on five separate days with 72 hour intervals. On the first measurement day, the athletes' height and weight measurements, 1-RM squat measurements, vertical jump performance measurements were taken and explosive strength levels were calculated using the Lewis formula. On the second measurement day, 5 repetitions were performed with 85% of the 1-RM squat and after 15 seconds of rest, the vertical jump performance test was measured. On the third measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 3 minutes of rest, the vertical jump performance test was measured. On the fourth measurement day, 5 repetitions of 1-RM squat with 85% were performed and after a rest period of 6 minutes, the vertical jump performance test was measured. Finally, on the fifth measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 9 minutes of rest, the vertical jump performance test was measured. After all measurements, explosive strength levels were calculated using Lewis formula. Passive rest was performed between the exercise and the measurement. Results: As a result of the findings of our research, it was determined that the 15-second rest time interval after the PAP protocol negatively affected the explosive strength performance level. In addition, there was no statistically significant difference between 3 min, 6 min and 9 min rest time intervals. Conclusion: It can be said that the most appropriate resting time is between 3-9 minutes in terms of increasing the explosive strength performance of wrestlers after the PAP protocol. Keywords: PAP, wrestlers, explosive power.

Acute Effects of Postactivation Potantiation on Explosive Strength Performance in Fitness Athletes

Aim: The aim of this research is to examine the effects of postactivation potantiation (PAP) on explosive strength performance in terms of the rest period and also to determine the optimal resting time for generating explosive strength after the PAP protocol. Methods: Ten fitness athletes were recruited for this study. The mean age of the participants group of the research was 26.60±1.07, their height was 178.50±3.02, their weight was 80.00±4.49, their maximal squat repetition performance (1-RM) was 130±7.45, their vertical jump performance was 53.80±1.98 and their explosive strength performance was 14.50±.47. In this research, measurements were completed on five seperate days with 72 hours intervals. On the first measurement day, the athletes' height and weight measurements, 1-RM squat measurements, vertical jump performance measurements were taken and explosive strength levels were calculated using the Lewis formula. On the second measurement day, 5 repetitions were performed with 85% of the 1-RM squat and after 15 seconds of rest, the vertical jump performance test was measured. On the third measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 3 minutes of rest, the vertical jump performance test was measured. On the fourth measurement day, 5 repetitions of 1-RM squat with 85% were performed and after a rest period of 6 minutes, the vertical jump performance test was measured. Finally, on the fifth measurement day, 5 repetitions of 1-RM squats with 85% were performed and after 9 minutes of rest, the vertical jump performance test was measured. After all measurements, explosive strength levels were calculated using Lewis formula. Passive rest was performed between the exercise and the measurement. Results: It was determined that explosive strength performance was negatively affected 15 seconds after the loading applied within the scope of the PAP protocol, and the difference between the pre-test and the post-test was statistically significant. Bat it was determined that there was no statistical difference between the pre-test and post-test in explosive strength performance 3 minutes after the loads applied within the scope of the PAP protocol. But also it was observed that the explosive strength performance was positively affected 6 minutes after the loading applied within the scope of the PAP protocol, and the difference between the pre-test and the post-test was statistically significant. Finally, it was determined that there was no statistical difference between the pre-test and post-test in explosive strength performance 9 minutes after the loading applied within the scope of the PAP protocol. Conclusion: As a result of this research, it has been determined that the optimal resting time for explosive strength generation is 6 minutes after the loading applied within the scope of the PAP protocol. In addition, it was determined that explosive strength performance was negatively affected after a short rest period of 15 seconds after the loading applied within the scope of the PAP protocol. In this context, it can be said that optimum performance can occur when fatigue is greatly reduced but the PAP effect is still present. Keywords: Postactivation Potantiation, Explosive Strength Performance, Complex Training

Effect of four different hamstring and quadriceps training protocols on explosive strength

The main objective of this study was to analyze more effective muscle work on some explosive strength performance variables. The secondary objectives were to determine how gender influences results and influence of the muscle work type on physiological parameters. Randomized controlled trial single-blind clinical trial, allocated by blocks and by sex. The study sample consisted of 80 healthy and active subjects divided into four muscle work groups: concentric, eccentric, concentric-eccentric and isometric. 4 sets of 12 repetitions, 1-min rest between series, were performed for dynamic workgroups. For the isometric work 6 s with 20 rest. 12-min time in 12 consecutive days. Main Outcomes Measures: sex, age, weight, height, body mass index, blood pressure and heart rate, jumping power, vertical jumping, horizontal jumping and speed 60 m. The concentric-eccentric group achieved the best results without statistically significant differences. The men improved the speed more by 60 m. Women improved in jumping power, vertical jumping and horizontal jumping. Results were statistically significant if p < 0.05. The group that performed the dynamic concentric-eccentric muscle work improved the performance variables analyzed further. Women are equally improved by men and heart rate dropped to the same extent. ClinicalTrials.gov ID: NCT03973060 (June 1; 2019)

Relationship between energy availability, energy conservation and cognitive restraint with performance measures in male endurance athletes

BackgroundLow energy availability in male athletes has gained a lot of attention in recent years, but direct evidence of its effects on health and performance is lacking. The aim of this research was to objectively measure energy availability (EA) in healthy male endurance athletes without pre-existing relative energy deficiency signs during pre-race season.MethodsTwelve trained endurance athletes (performance level 3, 4, and 5) participated in the cross-sectional controlled laboratory study. Fat-free mass, exercise energy expenditure, and energy intake were measured to calculate EA. Resting energy expenditure was measured and estimated to assess energy conservation. Three specific performance tests were used to assess endurance, agility, and explosive strength performance. For psychological evaluation, the Three Factor Eating Questionnaire and a short Well-being questionnaire were completed.ResultsMean EA was 29.5 kcal/kg FFM/day. The majority (66.6%) had EA under the threshold for low EA in females. Critical cognitive restraint (≥13) was reported by 75% of participants. There were no differences in performance, blood values, or psychological evaluation when subjects were divided into two groups divided by EA = 30 kcal/kg FFM/day. Cognitive restraint was negatively associated with measured resting energy expenditure and energy conservation (r = −.578, p = .025 and r = −.549, p = .032, respectively).ConclusionsThe mean EA measured in this study supports the theory that the threshold for low EA in endurance male athletes might be under the threshold for females. In addition, we confirmed cognitive restraint could be useful for early detection of energy conservation. The high cognitive restraint as measured in our sample stressed the need of eating behavior screening in endurance athletes in order to reduce risk of any disordered eating patterns.

Acute effect of a static- and dynamic-based stretching warm-up on standing long jump performance in primary schoolchildren.

The aim of the present study was to compare the acute effect of a static- vs dynamic-based stretching warm-up on standing long jump (SLJ) performance in primary schoolchildren. The sample was composed of 76 schoolchildren, 43 girls and 33 boys, aged 9–10 years old from three fourth-grade classes of Primary Education. The three groups were cluster-randomly assigned to the control (CG), static (SG) or dynamic (DG) groups. All the schoolchildren performed a standardized warm-up consisting of mobility exercises (five minutes), jogging (five minutes) and the SLJ test. Afterwards the CG schoolchildren received jump theory (eight minutes), the SG performed static stretching (eight minutes) and the DG performed dynamic-bounces stretching (eight minutes). Afterwards, all of them performed the SLJ test again. The results of the one-way ANOVA (F2,73 = 34.184; p < 0.001; η2p = 0.484), followed by the pairwise comparisons with the Bonferroni adjustment, showed that the DG students (MΔ = 11.07, SE = 1.42) made a significant statistical improvement in their SJL levels compared with the CG (MΔ = -3.00, SE = 1.89; p < 0.001, d = 1.51) and SG students (MΔ = -1.85, SE = 0.67; p < 0.001, d = 1.38). However, statistically significant differences between the CG and SG students were not found (p > 0.05, d = 0.12). The dynamic-bouncing stretch as a final part of a warm-up improves explosive strength performance in primary schoolchildren, and seems to be a good option before carrying out explosive strength activities of the lower body.

Intermittent Resistance Training at Moderate Altitude: Effects on the Force-Velocity Relationship, Isometric Strength and Muscle Architecture.

Intermittent hypoxic resistance training (IHRT) may help to maximize the adaptations following resistance training, although conflicting evidence is available. The aim of this study was to explore the influence of moderate altitude on the functional, neural and muscle architecture responses of the quadriceps muscles following a power-oriented IHRT intervention. Twenty-four active males completed two 4-week consecutive training blocks comprising general strengthening exercises (weeks 1–4) and power-oriented resistance training (weeks 5–8). Training sessions were conducted twice a week at moderate altitude (2320 m; IHRT, n = 13) or normoxia (690 m; NT, n = 11). Training intensity during the second training block was set to the individual load corresponding to a barbell mean propulsive velocity of 1 m·s−1. Pre-post assessments, performed under normoxic conditions, comprised quadriceps muscle architecture (thickness, pennation angle and fascicle length), isometric maximal (MVF) and explosive strength, and voluntary muscle activation. Dynamic strength performance was assessed through the force-velocity relationship (F0, V0, P0) and a repeated CMJ test (CMJ15MP). Region-specific muscle thickness changes were observed in both training groups (p < 0.001, = 0.02). A small opposite trend in pennation angle changes was observed (ES [90% CI]: −0.33 [−0.65, −0.01] vs. 0.11 [−0.44, 0.6], in the IHRT and NT group, respectively; p = 0.094, = 0.02). Both training groups showed similar improvements in MVF (ES: 0.38 [0.20, 0.56] vs. 0.55 [0.29, 0.80], in the IHRT and NT group, respectively; p = 0.645, < 0.01), F0 (ES: 0.41 [−0.03, 0.85] vs. 0.52 [0.04, 0.99], in the IHRT and NT group, respectively; p = 0.569, < 0.01) and P0 (ES: 0.53 [0.07, 0.98] vs. 0.19 [−0.06, 0.44], in the IHRT and NT group, respectively; p = 0.320, < 0.01). No meaningful changes in explosive strength performance were observed. In conclusion, contrary to earlier adverse associations between altitude and resistance-training muscle adaptations, similar anatomical and functional muscle strength responses can be achieved in both environmental conditions. The observed region-specific muscle thickness changes may encourage further research on the potential influence of IHRT on muscle morphological changes.

Effect of Different Core Exercises Applied During the Season on Strength and Technical Skills of Young Footballers

The aim of this study is to investigate the effect of two different types of core training applied during the season on the strength performance and football technical skills of young footballers. A total of 18 footballers average age was 15±0.8years voluntarily participated in the study. Two different core trainings were applied in addition to football technical skills. Before and after the study, the sit-up, standing long jump, push-up, dribbling, passing and shooting performances of players were observed. Data were assessed with the SPSS. In the dynamic group there were statistically significant improvements in all variables apart from shooting and passing, while the static group had statistically significant development of all variables apart from shooting. The control group only had statistically significant development for sit-up performance. While development sufficient to form significant differences between the variables observed in the experimental groups was not observed, there were significant differences for all variables when compared with the control group apart from shooting performance. In conclusion, footballers with eight-week dynamic and static core training added to in-season football training had similar levels of development in terms of strength and football technical skills, with significant development of strength, dribbling and passing skills when compared to a group without core training. In light of this data, eight-week dynamic and static strength training applied to footballers in the development period may be said to be an effective method to develop abdominal muscle strength and explosive strength performance and to develop dribbling and passing skills unique to football.

Acute changes in neuromuscular activity in vertical jump and flexibility after exposure to whole body vibration.

This study was aimed to investigate the neuromuscular activity after 10 minutes of exposure to a whole body vibration (WBV) session.Twenty male young adults (24.8 ± 2.5 year olds) were randomized and divided into 2 groups: the vibration group (VG) was exposed to 10 minutes of WBV at 35 Hz; performed 10 minutes of WBV at 35 Hz (displacement = 5 mm; magnitude = 5 g); the nonvibrated group (NVG) was the placebo group that maintained the same position on the plate but without exposure to any type of vibration. Subjects were evaluated with counter movement jump (CMJ) and muscular flexibility by means of electromyographic (EMG) analysis recorded on the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and gastrocnemius lateralis (LG).The 10 minutes of WBV showed an increase in muscular flexibility, associated with a decrease of EMG activity in BF (P < .01) and jump height. The latter was associated with a reduction of EMGs activity in BF (P < .01). The control group did not show any significant difference in all considered parameters.These results support the hypothesis that 10 minutes of WBV had effects on flexibility and explosive strength performance influencing neuromuscular behavior through inhibitor effects on antagonist muscles more than the stretch reflex activity on agonist muscles.

Comparative Recovery Periods in Men and Women to Optimize Post-Activation Potentiation via the Back Squat

Post-activation potentiation (PAP) is a theory that purports that the contractile history of a muscle can increase both peak force and rate of force development during subsequent contractions. PAP can benefit explosive athletes during competition or training by utilizing a conditioning contraction (CC), such as the back squat. Few (if any) studies, however, have examined gender differences in a protocol designed to maximize PAP. PURPOSE: To identify gender-specific recovery periods that maximize PAP during a countermovement jump (CMJ) following a 5RM back squat. METHODS: Twenty-four trained subjects (12M, 12F, 22 right leg dominant, 2 left leg dominant, Age = 21.2 ± 1.4 years, height = 1.70 ± 0.09 m, weight = 72.8 ± 14.2 kg) performed three maximal CMJs followed by a warm up set of 8-10 repetitions and a 5RM back squat CC. After seated recoveries of 5, 10, or 15 min, subjects performed three additional CMJs. Recovery periods were randomized among testing days. Individual 2x2 ANOVAs were conducted to evaluate the effects of gender and time on vertical jump height (VJH) and normalized electromyographical activity (NrmsEMG) of the right and left vastus lateralis (RVL, LVL) and medial gastrocnemii (RGM, LGM). RESULTS: For the entire sample, a significant increase VJH was observed with 5min recovery only (F(1,22) = 22.108, Meandiff = .017, p < .001, ηp2=.501). A significant decrease 10 min post CC was also seen in RVL NrmsEMG (F(1,22) = 6.111, Meandiff = -0.179, p = .022, ηp2=.217). A significant gender x time interaction was observed for RGM NrmsEMG at 10 min (F(1,22) = 10.742, p = .003, ηp2 = .328) with men showing an increase (pre = 2.87 ± 1.78, post = 3.12 ± 2.12) and women showing a decrease (pre = 1.93 ± .99, post = 1.66 ± .88). CONCLUSION: While gender differences were seen for EMG at 10 min, the only performance change was an increase in VJH by both genders after 5 min recovery. Thus, post-activation potentiation may be a viable method of acutely enhancing explosive strength performance in both trained men and women 5 minutes before the subsequent activity, but may cause increased fatigue and decreased muscle activity with extended rest (10+ min), particularly in the dominant leg.

Repeated sprint ability in soccer players: associations with physiological and neuromuscular factors.

The aim of this study was to examine the relationship between repeated sprint ability (RSA, 6×40 m [20+20 m] with 20-s recovery) and neuromuscular and aerobic fitness variables in male collegiate soccer players. Twenty-six players (age 22.5±3.6 years) were tested on separate days for countermovement jump (CMJ), squat jump (SJ), and standing long jump (LJ), and for maximal oxygen consumption (V̇O2max), velocity at onset of blood lactate accumulation (vOBLA), maximal aerobic speed (vV̇O2max), and peak blood lactate concentration (peak [La]). They were also tested for best and mean times on a repeated shuttle sprint ability test. RSA best time (r=-0.73 and r=-0.54) and RSA mean sprint time (r=-0.69 and r=-0.62) were significantly (P<0.01) correlated with LJ and CMJ, respectively. Significant correlations (P<0.05) were also found between RSA mean sprint time and sprint decrement with vOBLA (r=-0.44) and peak [La] (r=0.47), respectively. This study showed that RSA performance had a large to very large association with the individual level of jump performance and to a smaller extent to aerobic fitness variables in male collegiate soccer players. Given this finding, lower limbs' explosive-strength performance should be regarded as a relevant factor for male soccer.

Effects of Plyometric Training on Endurance and Explosive Strength Performance in Competitive Middle- and Long-Distance Runners

The purpose of this study was to examine the effect of a short-term plyometric training program on explosive strength and endurance performance in highly competitive middle- and long-distance runners. Athletes were randomly assigned to a control group (CG, n = 18, 12 men) and an explosive strength training group (TG, n = 18, 10 men). Drop jump (DJ) from 20 (DJ20) and 40 cm (DJ40), countermovement jump with arms (CMJA), 20-m sprint time, and 2.4-km endurance run time test were carried out before and after 6 weeks of explosive strength training. Also, the combined standardized performance (CSP) in the endurance and explosive strength test was analyzed. After intervention, the CG did not show any significant change in performance, whereas the TG showed a significant reduction in 2.4-km endurance run time (-3.9%) and 20-m sprint time (-2.3%) and an increase in CMJA (+8.9%), DJ20 (+12.7%), and DJ40 (16.7%) explosive performance. Strength training group also exhibited a significant increase in CSP, although the CG showed significant reduction. We conclude that properly programmed concurrent explosive strength and endurance training could be advantageous for middle- and long-distance runners in their competitive performance, especially in events characterized by sprinting actions with small time differences at the end of the race.

An Analysis of the Use of Proprioceptive Neuromuscular Facilitated Stretching Methods on Explosive Strength Performance in Wrestling

This paper is trying to analyze how proprioceptive neuromuscular facilitation (PNF) methods can improve muscular diastolic capacity. The research aims to identify the effect of using one of PNF method (Hold – Relax with agonist contraction) on explosive strength for wrestlers, and the Efficiency of the Reverse Body Lift skill performance for 16 volunteered healthy male wrestlers. Subjects classified into two Groups: Experimental and Control Group. Results reveal that post-measurement of 3 times of Bridge up test (Sec) significantly decreased (7.17±0.33, 6.4±0.37) for post and pre-measurements respectively. Flexible of spine (cm) significantly decreased (22.3±0.93, 20.57±1.01) for post and pre-measurements respectively, with improvement percentage of (7.09%) .Vertical distance (cm) significantly increased (18.61±0.90, 20.33±1.02) for pre and post-measurements respectively, with improvement percentage of (8.46%). Explosive strength (Sec) significantly decreased (13.61±1.41, 11.7±0.71) for post and pre-measurements respectively, with improvement percentage of (14.03%). Reverse Body Lift skill (cm) significantly increased (6.03 ± 0.57, 7.76 ± 0.97) for pre and post-measurements respectively, with improvement percentage of (22.29%), the most important conclusion was that applying training program that contains PNF exercises lead to an improvement of all physical variables, and led to the significant improvement in performance.

Influencia del estiramiento en el calentamiento para el salto y la velocidad

El objetivo del estudio es determinar si la realización de estiramientos pasivos, incluidos como parte del calentamiento, influyen en el rendimiento de la fuerza explosiva, en este caso en varios tests de salto vertical: Squat Jump (SJ), Countermouvement Jump (CMJ) y Reactive Jump (RJ); y también en un test de velocidad de 30 metros (mts.) con salida lanzada de 5 mts. Para ello, 9 jugadores del Málaga Club de Fútbol de categoría juvenil (18,22 ± 0,441 años) realizaron 2 protocolos de calentamiento en dos semanas consecutivas en su día de recuperación. Los jugadores de fútbol utilizan los estiramientos pasivos en su calentamiento y el tipo de esfuerzo al que se someten durante su actividad tiene un alto componente de fuerza explosiva de tipo balístico, movimientos que se ejecutan con gran intensidad y corta duración, tales como golpear el balón, sprints, cambios de dirección, saltos, etc. Se han encontrado disminuciones en el rendimiento de los test de SJ y RJ, así como también en el test de velocidad, obteniéndose valores significativos (p&lt;0,05) tanto para la potencia y el tiempo de vuelo del test RJ, como también para el test de velocidad. En cuanto al test CMJ, se han obtenido beneficios aunque las diferencias no han sido significativas. Por tanto, la realización de estiramientos pasivos influye de forma negativa en el rendimiento de la fuerza explosiva y la velocidad en una muestra de futbolistas entrenados.

Postactivation Potentiation Response in Athletic and Recreationally Trained Individuals

To determine if training status directly impacted the response to postactivation potentiation, athletes in sports requiring explosive strength (ATH; n = 7) were compared to recreationally trained (RT; n = 17) individuals. Over the course of 4 sessions, subjects performed rebound and concentric-only jump squats with 30%, 50%, and 70% 1 RM loads. Jump squats were performed 5 minutes and 18.5 minutes following control or heavy load warm-ups. Heavy load warm-up consisted of 5 sets of 1 repetition at 90% 1 RM back squat. Jump squat performance was assessed with a force platform and position transducer. Heavy load warm-up did not have an effect on the subjects as a single sample. However, when percent potentiation was compared between ATH and RT groups, force and power parameters were significantly greater for ATH (p < 0.05). Postactivation potentiation may be a viable method of acutely enhancing explosive strength performance in athletic but not recreationally trained individuals.