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Training for Muscular Power

Authors:
William J Kraemer at The Ohio State University
William J Kraemer
Robert Usher Newton at Edith Cowan University
Robert Usher Newton
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Abstract

In sport and everyday activities, the most important attribute of skeletal muscle is the ability to generate power, a product of strength and speed of movement. Many factors influence the muscle's ability to generate power. Training for muscular power requires special care in developing the proper exercise prescription. The need for muscular power runs across a spectrum of people from elite athletes attempting to optimize sports performance to the frail elderly trying to perform simple tasks. Power development is paramount to optimal neuromuscular function.
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Training for Muscular Power - Kraemer and Newton 20
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Training for Muscular Power - Kraemer and Newton 20
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All content in this area was uploaded by Robert Usher Newton on Jun 24, 2015
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Training for Muscular Power - Kraemer and Newton 20
01.pdf
Content uploaded by Robert Usher Newton
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All content in this area was uploaded by Robert Usher Newton on Jun 24, 2015
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... At the professional level, players are involved in intense physical collisions, occurring on average 2 collisions every 3 minutes, while travelling at high-speed (13,21). During rugby league matches, players rapidly generate high levels of force over a short period to quickly move off the try line in defence or recover from a tackle to rapidly play-the-ball in attack (23,35). Muscular power has previously been associated with several performance-related qualities, such as tackle ability, evasive skills, and successful carries, and has been shown to discriminate between skill level (3,9,37,39). ...
... The season was categorized as 15 weeks of pre-season (where 3 trial matches were played) and 18 weeks of competition. The competition was further categorized as early competition (;weeks [16][17][18][19][20][21], mid-competition (;weeks [22][23][24][25][26], and late competition (;weeks 27-34) (12) (Figure 1). ...
Seasonal Muscular Power Changes: Considerations of Concurrent Resistance and Field-Based Training in Professional Rugby League
Article
  • Jul 2024
  • J STRENGTH COND RES
Redman, KJ, Wade, L, Whitley, R, Connick, MJ, Kelly, VG, and Beckman, EM. Seasonal muscular power changes: considerations of concurrent resistance and field-based training in professional rugby league. J Strength Cond Res XX(X): 000-000, 2024-A rugby league player's ability to develop or maintain lower-body power will be significantly influenced by the resistance and field-based training loads completed. This study aimed to examine the power changes across a rugby league season and to investigate the relationship of concurrent training and training experience on power changes. Eighteen rugby league players participated in this study. Lower-body power was evaluated using a countermovement jump throughout the season. Four measures of external training loads were collected. A Friedman's test was used to assess differences in power throughout different phases of the season. A series of Spearman's rank-order correlations were conducted to assess the relationship between percentage changes in power during the training block, external training loads, and training experience. Countermovement jump peak velocity significantly decreased from the start (p = 0.006) and end of pre-season (p = 0.022) to the late competition. Correlation analysis revealed a large significant association between early competition field-based external loads (relative (rs = -0.571) and total distance (rs = -0.628)) and change in peak power. Very large significant negative relationships were also observed between mid-competition volume load with change in peak force (rs = -0.825) and peak power (rs = -0.736). Training experience was not significantly associated with changes in muscular power variables throughout this study. Coaches should seek to monitor changes in peak power when competition begins and to assist with decision-making for potential adjustments to running volume and intensity during field-based sessions.
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... Lower-limb muscle power is acknowledged as a proxy of overall physical performance [1] given its associations with important physical function measures, including muscle strength [18], balance [19,20], and mobility [5,21]. This highlights the importance of actively monitoring lower-limb muscle power using valid, feasible, and comparable assessment methods. ...
... We observed significant associations between lower-limb muscle power measures and physical performance. These findings are in line with several previous studies [18,[36][37][38][39] and support the view of experts in the field [1,2,39] and internationally recognized associations [40,41] that this physical capacity should be actively monitored in older adults. Bean et al. [5] examined data from the InCHIANTI study and found significant associations between leg power and global physical performance. ...
Agreement and Associations between Countermovement Jump, 5-Time Sit-To-Stand, Lower-Limb Muscle Power Equations, and Physical Performance Tests in Community-Dwelling Older Adults
Article
Full-text available
  • Jun 2024
Objectives: The present study examined the agreement and associations of the 5-time sit-to-stand (5STS) test, the countermovement jump test, and lower-limb muscle power equations with a set of physical performance tests in older adults. Methods: Five hundred and thirty-four community-dwelling older adults were recruited for the study. Lower-limb muscle power measures included 5STS, the countermovement jump test, and muscle power equations. Isometric handgrip strength, timed “up-and-go!”, the 6 min walking test, one-leg stand, and walking speed at usual and fast paces were used to assess physical performance. Pearson’s correlations and Bland–Altman analyses were conducted to examine associations among muscle power measures. Linear and multiple regressions were run to explore associations of 5STS, the countermovement jump test, and muscle power equations with physical performance tests. Results: Weak correlations were observed among lower-limb muscle power measures. Bland–Altman results indicated important differences among the countermovement jump test, 5STS, and muscle power equations. Results of multiple linear regressions indicated that 5STS, the countermovement jump test, and muscle power equations were significantly associated with measures of muscle strength and mobility. However, only 5STS was significantly associated with balance. Conclusions: Our results indicate that the performance on the countermovement jump test and 5STS is weakly correlated with lower-limb muscle power equations. The only exception was the correlation found between the countermovement jump test and relative muscle power, highlighting the importance of accounting for body mass in muscle power evaluations. Muscle power measures were similarly associated with performance on handgrip strength, timed “up-and-go!”, and the 6 min walking test. The exclusive association of 5STS with balance suggests that a reassessment of 5STS muscle power equations may be warranted.
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... Muscular strength is the ability to exert maximal force in one single contraction [33]. Muscular power refers to a great force production over a short period of time, such as in fast leg kicks and explosive jumping [34]. Nineteen studies examined muscle power [6,[17][18][19][20][21][24][25][26][35][36][37][38][39][40][41][42][43][44]. ...
The Importance of Physical Fitness Parameters in Rhythmic Gymnastics: A Scoping Review
Article
Full-text available
  • Sep 2024
This scoping review presents an overview of physical fitness parameters in rhythmic gymnastics as well as the association of fitness with gymnasts' performance, competitive level, and age. PubMed, Scopus, and Sport Discus databases were searched. Of the 586 records retrieved, 41 studies met the inclusion criteria (n = 1915 participants). The included studies examined flexibility, aerobic capacity, muscle power, muscle endurance, muscle strength, sprint speed, agility, balance, and coordination. Performance was associated with flexibility, aerobic capacity, lower-limb muscle power, agility, muscular endurance, balance, and coordination from a young age. Flexibility, aerobic capacity, and muscle power were, in general, higher in high-level gymnasts than in low-level gymnasts or controls. Older rhythmic gymnasts demonstrated higher scores than the younger ones in flexibility, aerobic capacity, balance, and sport-specific coordination but not in muscle endurance, while some studies reported a decline in muscle power with age. Supplementary physical fitness training improved all physical abilities irrespective of the gymnasts' level. Rhythmic gymnastics training alone improved muscle power, agility, speed, muscular endurance, and balance to a lesser extent than targeted fitness training. Muscular strength, speed, and agility are largely under-researched in rhythmic gymnastics. Emphasis should be given to targeted strength and power training due to the high mechanical loads placed on skeletally immature athletes.
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... Ability to generate high muscular power is essential to success in many athletic and sporting activities [1,2]. In general, resistance training (RT) consisting of ballistic or explosive exercises are considered highly specific to maximal power movements and develops many of the components of the neuromuscular systems facilitating such actions [3]. There are two main schools of thought concerning the optimum loads for power training [1]: one is the use of light-load (<50% of one repetition maximum [1RM]) and the other heavy-load (50-70% of 1RM). ...
Resistance training leading to repetition failure increases muscle strength and size, but not power-generation capacity in judo athletes
Article
Full-text available
Strength-trained athletes has less trainability in muscle size and function, because of their adaptation to long-term advanced training. This study examined whether resistance training (RT) leading to repetition failure can be effective modality to overcome this subject. Twenty-three male judo athletes completed a 6-week unilateral dumbbell curl training with two sessions per week, being added to in-season training of judo. The participants were assigned to one of three different training programs: ballistic light-load (30% of one repetition maximum (1RM)) RT to repetition failure (RFLB) (n = 6), traditional heavy-load (80% of 1RM) RT to repetition failure (RFHT) (n = 7), and ballistic light-load (30% of 1RM) RT to non-repetition failure (NRFLB) (n = 10). Before and after the intervention period, the muscle thickness (MT) and the maximal voluntary isometric force (MVC) and rate of force development (RFDmax) of elbow flexors were determined. In addition, theoretical maximum force (F0), velocity (V0), power (Pmax), and slope were calculated from force-velocity relation during explosive elbow flexion against six different loads. For statistical analysis, p < 0.05 was considered significant. The MT and MVC had significant effect of time with greater magnitude of the gains in RFHT and NRFLB compared to RFLB. On the other hand, all parameters derived from force-velocity relation and RFDmax did not show significant effects of time. The present study indicates that ballistic light-load and traditional heavy-load resistance training programs, leading to non-repetition failure and repetition failure, respectively, can be modalities for improving muscle size and isometric strength in judo athletes, but these do not improve power generation capacity.
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... Traditional resistance training exercises (e.g., squats) involve individuals lifting moderate to heavy weights (e.g., 60-90% of one repetition maximum [1RM]), generating constant tension in the musculature, usually through the use of external loads (e.g., barbells and dumbbells) (C. S. Santosh et al., 2022). In contrast, ballistic training exercises involve the projection of the individual's own body (e.g., plyometric jump) or an external implement (e.g., barbell, medicine ball; usually at ≤ 30%1RM (Kraemer & Newton, 2000)) into a flight phase (Moir et al., 2018), thus attaining a higher movement velocity. The key difference between the two training methods is the load magnitude (moderate-heavy vs. low), which leads to the exercises being performed at different velocities (e.g., squat vs. squat jump [SJ]) . ...
Effects of complex training compared to resistance training alone on physical fitness of healthy individuals: A systematic review with meta-analysis
Article
Combining traditional resistance and ballistic exercises in a complex training (CT) format has shown improved physical fitness compared to the control conditions. However, no meta-analysis has directly compared CT with traditional resistance training (RT) alone. A systematic search was conducted in PubMed, Scopus, and WoS. Thirty-two studies involving 726 participants were included. Both RT and CT similarly improved one-repetition maximum (1RM) squat and bench press, 10 m and 30-60 m linear sprint time, squat jump height, jump power, reactive strength index, and standing long jump distance. Compared to RT, CT favoured 5-m (ES=0.96) and 20-m linear sprint (ES=0.52), change-of-direction speed (CODS; ES=0.39), and countermovement jump height (CMJ; ES=0.36). Furthermore, moderating effects of training frequency, duration, and complex training type were reported. Certainty of evidence was considered low for 5-m and 20-m linear sprints and CODS and very low for other outcomes. Compared to traditional resistance training, complex training may improve 5-m and 20-m linear sprints, CODS, and CMJ height. The effects of complex training may be optimised by longer interventions (≥7 weeks), with ~3 weekly training sessions, and using ascending and contrast training formats. However, the certainty of evidence ranges from very low to low.
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... Zumba fitness is known for its dynamic integration of movement and music, providing a stimulating experience that encourages self-expression and activates different aspects of one's personality (Kaufmann, 2011;Studer-Lüthi & Züger, 2012). Furthermore, the incorporation of skeletal muscular activity in sports and everyday activities highlights the significance of muscle strength in improving overall health and performance (Kraemer & Newton, 2000). In the study conducted by Puspodari et al. (2022), titled "Effectiveness of Zumba Exercise on Maximum Oxygen Volume, Agility, and Muscle Power in Female Students, " it was found that Zumba exercise, performed for 30 minutes at 80% of maximum heart rate (HRmax), three times per week over an 8-week period, led to significant improvements in maximum oxygen volume (VO 2 max), agility, and muscle power among female students at Universitas Nusantara PGRI Kediri, East Java, Indonesia. ...
Physiological Effects of Zumba Exercise on Male College Students: An Intervention Study
Article
Full-text available
  • Jun 2024
Objectives. This study aimed to assess the effectiveness of Zumba exercise in improving physiological parameters among male students enrolled in an aerobic exercise program in Gwalior, Madhya Pradesh, India. Materials and methods. A one-group pre-post-test design was used, involving fifteen male students aged betweennineteen and twenty-four years old. The participants engaged in Zumba sessions supervised by health professionals three times per week for eight weeks. A series of measurements, including VO₂max, agility, and muscle strength, was evaluated at pretest and posttest stages using various equipment and methods. Results. Statistical analysis using SPSS version 26 software included normality testing with the Shapiro-Wilk test and a significance level set at p ≥ 0.05. A paired sample t-test was performed to compare pretest and posttest measurements of VO₂max, agility, and muscle strength. The results are presented as Mean ± Standard Deviation (SD). The findings reveal significant improvements in all parameters assessed post-intervention. VO₂max increased from 26.5 ± 4.5 to 30.8 ± 4.2 mL/kg/min, agility improved from 15.8 ± 1.2 to 14.6 ± 1.3 seconds, limb muscle strength increased from 394.2 ± 66.4 to 411.1 ± 67.5 joules, and arm muscle strength increased from 123.5 ± 17.1 to 138.2 ± 13.9 joules (all p ≤ 0.001). These results demonstrate the effectiveness of Zumba exercise in enhancing physical fitness among male college students. Conclusions. The findings suggest that Zumba exercise is an effective non-pharmacological intervention for enhancing cardiovascular fitness, agility, and muscular strength among male students. Integrating Zumba exercise into regular physical activity routines may contribute to stimulating an active lifestyle and improving overall health outcomes.
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... Improving power can result in enhanced athletic performance in disciplines that demand speed and explosive strength. Power can be measured and evaluated through various tests and methods, such as the vertical jump (e.g., CMJ) and short-distance sprinting (Kraemer & Newton, 2000). CMJ serves as a reliable measure for assessing an athlete's explosive power and lower-body strength (Bosco et al., 1983).These assessments assist coaches and athletes in understanding the level of explosive capability and in designing specific training programs to enhance it. ...
Efectos del entrenamiento combinado pliométrico, de fuerza, velocidad y cambio de dirección en el rendimiento físico de jugadores jóvenes de fútbol masculino: Un ensayo controlado aleatorio (Effects of combined plyometric, strength, speed and change of direction training on youth male soccer players physical performance: A randomised controlled trial)
Article
Full-text available
  • May 2024
El objetivo de este estudio es determinar la influencia del entrenamiento pliométrico a corto plazo o del entrenamiento combinado (6 semanas) dentro de la práctica regular de fútbol en los saltos y las acciones de cambio de dirección de jóvenes jugadores de fútbol durante la temporada. Treinta jugadores fueron asignados al azar a tres grupos: pliometría (PL), pliometría + velocidad + cambio de dirección (COD) (COMB1) o PL + velocidad + COD + fuerza (COMB2). Todos los jugadores entrenaron 3 veces por semana y los grupos experimentales cambiaron el calentamiento táctico típico por un programa propuesto de pliometría o entrenamiento combinado durante 20 minutos (2 días por semana) durante 6 semanas. Antes y después del entrenamiento, se analizaron los saltos con contramovimiento con brazos libres (CMJA) y las pruebas L-RUN. El análisis dentro de los grupos mostró mejoras significativas en CMJA (ES: 0.73;1.27;1.16) en COMB1, COMB2 y PL, mientras que COMB1 y COMB2 también mostraron mejoras significativas en las pruebas COD (ES: 3.75; 2.15). El análisis entre grupos mostró mejoras significativas mayores en las variables de COD (p ≤ 0.001; p ≤ 0.001) en los grupos experimentales en comparación con PL. Finalmente, COMB1 y COMB2 no mostraron mejoras significativas en L-Run (p ≤0.234). La sustitución de algunos ejercicios de fútbol de baja intensidad con pliometría combinada con fuerza, sprints y COD durante el calentamiento podría ser una opción posible para optimizar la capacidad de salto y cambio de dirección durante el entrenamiento de fútbol en temporada. Palabras clave: agilidad, salto vertical, velocidad, aceleración, jugador de fútbol, pliometría, fuerza. Abstract. The objective of this study is to determine the influence of short-term plyometric or combined training (6 weeks) within regular soccer practice on the jumping and change of direction actions of young soccer players during the season. Thirty players were randomly assigned to three groups: plyometrics (PL), plyometrics + speed + Change of direction (COD) (COMB1), or PL + speed + COD + strength (COMB2). All players trained soccer 3 times per week and the experimental groups change the typical tactical warm up with a proposed PL or combined training program for 20 minutes (2 days per weeks) for 6 weeks. Before, after training, free-arm countermovement jump (CMJA) and L-RUN tests were analysed. Within-group analysis showed substantial improvements in CMJA (ES: 0.73;1.27;1.16) in COMB1, COMB2 and PL while COMB1 and COMB2 also showed substantial enhancements in COD tests (ES: 3.75; 2.15). Between-group analysis showed substantially greater improvements in COD variables (p ≤ 0.001; p ≤ 0.001) in experimental groups in comparison to PL. Finally, COMB1 and COMB2 showed no significant enhancements in L-Run (p ≤0.234). The replacement of some low-intensity football drills with PL combined with strength, sprints and COD. during warm-up may be a possible option to optimise jumping and change of direction ability during in-season football training. Keywords: agility, vertical jump, speed, acceleration, soccer player, plyometrics, strength.
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... Further study limitations that complicate the between-study comparison can be assumed to be high heterogeneity in the participants' strength levels, sports, or ages [23]. Suchomel [24] hypothesized a non-linear relationship between back squat performance and speed-strength capability, like sprinting or jumping, since a diminished influence of maximal strength in high strength level athletes is expected [25], due to a saturation effect. Suchomel [24] categorizes REL into three different strength levels for the squat performance. ...
Do small samples bias the correlation between strength and jump performance? Multivariate insights into age and sex amidst strength saturation: an analysis of 1,544 participants from different sports
Article
Full-text available
  • May 2024
  • BIOL SPORT
Objectives Maximal strength is considered a fundamental aspect of athletic performance across a wide range of sports and is also needed for a range of activities of daily life. Yet, compared to males there are fewer publications examining females, with most showing similar coefficients of correlation between dynamic strength and different athletic performances. In both, males and females, results are biased by mostly small sample sizes (sample bias) leading to a fluctuation around the true correlation coefficient of the entire population. Material and methods This cross-sectional analysis involving 1544 participants employed multivariate and correlative analyses to clarify the importance of maximum strength in the parallel back squats on the jump performance controlling for variables such as type of sport, sex, age, and performance level. Results The analysis revealed two principal components that reflect distinct types of variability within the dataset: the first, primarily associated with performance capabilities, accounts for 58.45% of the variance, while the second, emphasizing demographic differences, accounts for a considerably lower variance of 25.08%. The correlation analyses in this study identified maximal strength as a significant factor influencing jumping performance, accounting for 48-53% of the variance in jump height. Conclusions The analysis presents a saturation curve, with potential diminishing returns at higher strength levels. Age and sex had little to no effect on overall correlation coefficients. The overall correlation coefficients and the analyses for the subgroups (by sport and performance level) can differ considerably, which can be explained (mathematically) by the artificial formation of clusters, homogeneous subject groups, or small sample sizes.
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Acute effect of adding whole body vibration exercise during inter-sets recovery period on muscular performance during high velocity—low resistance weightlifting exercisesAkuter Effekt der Hinzufügung einer Ganzkörper-Vibrationsübung während der Erholungsphase auf die Muskelleistung bei Gewichtheberübungen, die mit hoher Geschwindigkeit und gegen geringen Widerstand ausgeführt werden
Article
  • Nov 2024
Numerous studies have shown that whole-body vibration exercise can result in performance benefits. This potential effect when practicing repeated exercises nevertheless remains poorly understood. The purpose of this study was to evaluate the acute effect of adding whole-body vibration exercise during the recovery period on power, kinetic, and muscular activity during repeated weightlifting exercises at high speed and against a low resistance. Thirteen male physical education students completed 3 training sessions in bench press and/or squat during which they had to perform 10 sets of 6 repetitions with the highest possible speed during the concentric phases (load equal to ~33 ± 6% 1 RM). Series were separated by 3 min of passive recovery. During 2 of the 3 training sessions, participants were asked to perform 30 s of push-ups or dynamic squats in the middle of the recovery time on a vibrating platform with or without vibrations (frequency: 40 Hz; amplitude: 2 mm). Power output, vertical velocity and muscular activity of the upper or lower limbs were measured during each bench press or squat movement. Statistical analysis revealed that peak and average power and velocity as well as muscle activation levels were not significantly different between the 3 training sessions. Several factors related to the characteristics of the vibration stimulus, the modalities of recovery and the design of the training session could explain in the present study the absence of effect on performance. The potential positive effect of a whole-body vibration exercise on performance during repeated strength training exercises therefore remains to be demonstrated.
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Effect of combined concentric and eccentric strength training and detraining on force-time, musele fiber and metabolic characteristics of leg extensor muscles
Article
Full-text available
  • Jan 1981
1 Finland HÄKKINEN K., KOMI P.V. & TESCH P.A. Effect of ccmbined concentric ard eccentric strength training and detraining on force-time, muscle fiber-and metabolic characteristics of leg extensor muscles. Scand. J ,Sports Sci. 3 (2): 50-58, 1981. Prog¡essive strength training of combined concentric and eccentric contractions were performed three times a week for 16 weeks by 14 males {20-30 yrs of age) accustomed to weight training. The training peeriod was iollowed bv 8 weeks of detraining. The training program consisted mainly of dynamic exeicises for the ieg-extensovs with loads of 80 to 120 of one maximum repetition The training caused significant improvements in-maximal force (p < 0.001) and various force-time (p (0.05-4.01) para¡àeters. Du¡ing thg I'ast trarning àionìh tbe inãrease in force was gireatly tri¡nited' and there was ¿ decrease in th,e force-time parameters. The marked improvements in mwcle strength were accompanied by ccnsiderable intemål qdaptatioos ,Ín-ttre tnaCned muscle, as Judged from l¡rcreases (p < 0-001) ,iqr. the fibet ãeas ôt tËe Ïast fi¡¡itch (FT) and slow twitch (ST) fibers. Durlng early conditioning improvement i! the qqgs! jump w,as related to tl.e relãtive hypertrop]ty of tr1l ii¡eis fo <0.01). No sier¡j-Êi,cå,r¡t ct¡anges ,in tJre er¡zyme aittv¡tiês oi mÍoki¡¡ase-a¡¡d creatine kirmse were found as a result of-tra¡rrir}g, but i,ndividt¡al charrges in my-o-kinase activity $/ere related to the relative. hypertrop'hy of FT fibers-(p ç 0.05) and Improvernent i+ the squat jump (p < O.Of)-during early conditiontuag. All the ada,p-iatlo:ns'-incilcating musõle hypertrophy occurred. prtm@lv during the last two training mo¡rths. Decreases (p (0.001) in maxirnal force during the detrairring were accompâ-nied bv a sisrificår¡t rediuction in the fi¡b,er areas of ttle fC tp < 0.01) and ST (p < 0.05) tvpes end by a change in bödy-antliropometry.-A periodiè-and partial usage. of àccentr-ic contráctions,-together with conèentric training' is suggested to be effectiùe in training for-maximal force and äso for force-time eharacteristics. In training of longer durations the specific effects of strength trainlng are-obviot¡s and explaiñable by adaptatlons in the trained muscle. Keg tenns: erìzJûne actlvities, muscle mechanics, muscle metabollsn, muscle streng:th.
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Specific Movement Power Related to Athletic Performance in Weight Lifting
Article
Full-text available
  • Feb 1996
In order to evaluate how mechanical power relates to athletic performance in weight lifting, specific movement power (SMP) was investigated using a newly developed dynamometer. Four simulated pull movements in weight lifting were measured: weight lifting pull (WL), second pull, back strength pull, and shoulder shrug pull. Subjects included 12 elite (EL) and 14 district (DI) level Japanese weight lifters. Athletic performance was defined as the highest total combined weight (snatch plus clean and jerk) lifted during competition. The highest SMP was observed in the WL. Force, velocity, and power relations were derived from the WL, showing higher velocity and power values in EL than DI at an identical force level. SMP in WL was found to be significantly correlated to athletic performance. SMP measured as a simulated pull movement in weight lifting employing the present dynamometer appears useful in evaluating athletic performance. Furthermore, this dynamometer provides force-velocity relationships during multiarticular explosive movements.
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Changes in electrical and mechanical behavior of leg extensor muscles during heavy resistance strength training
Article
  • Jan 1985
To investigate the influence of strength training on the electrical and mechanical behaviour of leg extensor muscles during concentric and various stretch-shortening cycles exercises, eleven male subjects went through dynamic heavy resistance strength training with loads of 70 to 120% one maximum repetition three times a week for 24 weeks. The heavy resistance strength training resulted in specific changes in neuromuscular performance. This was demonstrated by the great (p< 0.001) shift of primarily the high force portions of the force velocity curves measured both during squat (SJ) and counter movement jumping (CMJ) conditions. An increase of 30.2% (p<0.001) in maximal strength was noted during the training, while the increases became gradually smaller near the high velocity portions of the curve, where an increase of 7.3% (p<0.05) in the jumping height in SJ and a non-significant increase in the maximal extension velocity with free loads were noted. The increases in positive work phases of force production were accompanied by significant (p<0.05) increases in the neural activation (IEMG) of primarily the vasti medialis and lateralis muscle, while only slight changes were noted in the RF muscle. Only minor and mostly nonsignificant changes were observed during the strength training in the neural activation and force production of the leg extensor muscles in various drop jumps, in which high contraction velocities are utilized. When the training was followed by a 12-week detraining, a great (p<0.001) decrease in maximal strength was observed, while the changes in various parameters of explosive force production were either small (p<0.05) or nonsignificant. The present findings regarding the changes in the electrical and mechanical behaviour of the leg extensor muscles during heavy resistance strength training give additional support to the concept of specificity of training.
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