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A Biomechanical Evaluation of Resistance: Fundamental Concepts for Training and Sports Performance
Abstract
Newton's second law of motion describes the acceleration of an object as being directly proportional to the magnitude of the net force, in the same direction as the net force and inversely proportional to its mass (a = F/m). With respect to linear motion, mass is also a numerical representation of an object's inertia, or its resistance to change in its state of motion and directly proportional to the magnitude of an object's momentum at any given velocity. To change an object's momentum, thereby increasing or decreasing its velocity, a proportional impulse must be generated. All motion is governed by these relationships, independent of the exercise being performed or the movement type being used; however, the degree to which this governance affects the associated kinematics, kinetics and muscle activity is dependent on the resistance type. Researchers have suggested that to facilitate the greatest improvements to athletic performance, the resistance-training programme employed by an athlete must be adapted to meet the specific demands of their sport. Therefore, it is conceivable that one mechanical stimulus, or resistance type, may not be appropriate for all applications. Although an excellent means of increasing maximal strength and the rate of force development, free-weight or mass-based training may not be the most conducive means to elicit velocity-specific adaptations. Attempts have been made to combat the inherent flaws of free weights, via accommodating and variable resistance-training devices; however, such approaches are not without problems that are specific to their mechanics. More recently, pneumatic-resistance devices (variable) have been introduced as a mechanical stimulus whereby the body mass of the athlete represents the only inertia that must be overcome to initiate movement, thus potentially affording the opportunity to develop velocity-specific power. However, there is no empirical evidence to support such a contention. Future research should place further emphasis on understanding the mechanical advantages/disadvantages inherent to the resistance types being used during training, so as to elicit the greatest improvements in athletic performance.
... Apart from the types of exercises these machines are designed for, the most relevant characteristic of a bodybuilding machine is the nature of the resistance source. Three different categories, based on the source of the resistance force, were described by Frost et al. (Frost, Cronin, and Newton 2010): ...
... Isoinertial or free-weight resistance is the most extended method to enhance strength and power capacity (Frost, Cronin, and Newton 2010). Free-weight resistance is also known as constant resistance, where the term "constant" may be due to the use of constant masses (weight), which do not change throughout the exercise. ...
... Since the exercise motion patterns and the muscle activation depend on the resistance source of the bodybuilding machine, new devices with different resistance force characteristics are of interest (Chen et al. 2018;Biscarini and Contemori 2018;Whinton et al. 2018). Frost et al. (Frost, Cronin, and Newton 2010) emphasizes that a greater understanding of the biomechanical properties governing each type of resistance, and/or how they can be manipulated, will provide a much greater appreciation of the benefits and limitations associated with each resistance training modality. ...
... R ecently, the focus on eccentric muscle actions and associated training techniques has increased substantially. For strength and conditioning (S&C) and sports science practitioners, this uptake is associated with the ever-growing research (4,5,14,21,22,25,30) recognizing the unique adaptations following eccentric training (21,28). Eccentric muscle lengthening occurs in several daily tasks, including walking downstairs and lowering to sit on a chair (20). ...
... Eccentric muscle lengthening occurs in several daily tasks, including walking downstairs and lowering to sit on a chair (20). Furthermore, eccentric muscle actions are present in sporting tasks, such as sprinting, landing, and downhill skiing (14,27,30,31). The muscle action is primarily believed to act as a damper to dissipate and release energy or increase concentric force output during stretch-shortening cycle (SSC) tasks (4,23,35,42). ...
... For an in-depth review of AEL, please refer to both Wagle et al. (45) and Moore et al. (32). In addition, it is important to note that during supramaximal AEL ( J Hook back squat as an example), during the initial lowering phase (top to half-squat position) as a result of mechanical advantage, individuals are stronger during this portion of an exercise (14,41). Because of this, the supramaximal concentric loads may not yield an eccentric overload during this portion of the lift. ...
Various methods of eccentric training that aim to increase muscle mass or reduce ground contact time during a landing task have been extensively researched and practically examined. However, multiple methods to implement eccentric training currently exist; they differ in execution and intended training adaptions. There is a clear differentiation between an eccentric muscle action and an eccentric motion whereby a motion alludes to a downward movement of an exercise. The proposed eccentric motions are dissipating eccentrics, deceleration eccentrics, overcoming eccentrics, maximal eccentrics, and rebound eccentrics. These motions formulate into training methods and cues to allow practitioners to clearly differentiate the various eccentric training methods used in research and practice. This review proposes a new conceptual framework that clearly outlines the different forms of eccentric motions that fall into a desired eccentric training method.
... Constant resistance is defined as a constant external load throughout the range of motion; regulated resistance is defined as a constant velocity load that provides a controlled speed throughout the range of motion; whereas fluid-based resistance is similar to regulated and variable resistance and has two types: hydraulic resistance and pneumatic resistance (McMaster et al., 2009). Variable resistance is defined as the type of resistance that changes during exercise (Frost et al., 2010). ...
... Research has demonstrated the feasibility of using kinetic data as real-time feedback information to athletes and for monitoring purposes, e.g., velocity-based resistance training uses movement speed values fed by linear sensors to keep athletes moving in specific speed intervals as much as possible to achieve training objectives (Jovanović and Flanagan, 2014). Power was assumed to be better indicator of the difference in explosive power between the two groups of athletes than speed in previous studies comparing free weight resistance with pneumatic resistance: whether monitored for a single training movement or the entire intervention (Frost et al., 2010;Franchini et al., 2011;Frost et al., 2016). In this study, power was chosen as the indicator for real-time feedback information and monitoring. ...
... 2. The downward pull of the air pressure on the light barbell is the primary source of load during squatting with pneumatic resistance. This downward pull counteracts the effects of inertia and momentum in the squatting process, resulting in a consistently high level of muscle effort throughout the centripetal phase of the squat (i.e., the muscle effort required in the second half of the squatting process is not significantly reduced by the increases in inertia and momentum) (Frost et al., 2010). Thus, the decreasing magnitude of inertia and momentum caused the difference in power output between the two groups during the centripetal phase. ...
Objective: The present study compared the effects of two different resistance types (pneumatic resistance and free weight) of 6-week squat training on the performance for young female judo athletes in linear speed and vertical jump by utilizing the maximum power of each set of squats in each training session as the monitoring vehicle. Monitoring data were used to assess the effects and trends of the two resistance types on 70% 1RM weight-bearing during the 6-week intervention training. Methods: In a 6 weeks squat training (2 reps/week with a constant load), 23 adolescent female judo athletes (Age span: 13-16 years, 14.58 ± 0.96) were randomly selected and then divided into the traditional barbell (FW) group (n = 12) and the pneumatic resistance (PN) (n = 11) group according to different resistance types (free weight and pneumatic resistance), with 10 in FW group and 9 in PN group actually completed the study. Before and after training, the 30-m Sprint time (T-30M), vertical jump height and relative power (countermovement jump, static-squat jump, and drop jump), reactive strength index (DJ-RSI), and maximal strength were assessed. One-Way ANOVA was used to examine the pre-test differences of groups (FW and PN). A 2-factor mixed-model analysis of variance was used to examine the independent effects of group (FW and PN) and time (pre and post) on each dependent measure. Scheffe post hoc comparisons were used to examine the differences. Pre-and post-experimental differences between the two groups were analyzed using independent samples t-tests and magnitude-based inferences (MBI) derived from their p values, and effect statistics were applied to compare the pre-and post-changes exhibited by each group to identify the potential beneficiary groups. Results: The PN group outperformed the FW group in terms of maximal power output per training session (822.5 ± 55.22 vs. 927.42 ± 48.15, conventional vs. pneumatic, p < 0.001, effect size = −2.02). After 6 weeks of training, the FW group showed significant increases in vertical jump height and relative strength (CMJ, SJ, DJ), with no significant gains observed in T-30 and maximal strength. The PN group showed significant improvements in maximal strength; however, no significant improvements were observed in the other tests. In addition, there was no significant difference in DJ-RSI between the two groups before and after training. (2023), Effects of lower-extremity explosive strength on youth judo athletes adopting different types of power-based resistance training.
... Over the past 160 years, various equipment has been invented to transfer external resistances onto skeletal muscles for resistance exercise [34,35]. Each equipment has advantages and disadvantages [19,34,[36][37][38]. ...
... Over the past 160 years, various equipment has been invented to transfer external resistances onto skeletal muscles for resistance exercise [34,35]. Each equipment has advantages and disadvantages [19,34,[36][37][38]. Some disadvantages might be mechanical, such as the way the resistance is transferred to the body. ...
... Other disadvantages might be practical, such as machine size, weight, and cost. Below, we focus on mechanical aspects, and we refer readers elsewhere for further discussions on practical considerations of various resistance exercise equipment [19,[34][35][36][37][38]]. ...
Eccentric resistance exercise emphasizes active muscle lengthening against resistance. In the past 15 years, researchers and practitioners have expressed considerable interest in accentuated eccentric (i.e., eccentric overload) and eccentric-only resistance exercise as strategies for enhancing performance and preventing and rehabilitating injuries. However, delivery of eccentric resistance exercise has been challenging because of equipment limitations. Previously, we briefly introduced the concept of connected adaptive resistance exercise (CARE)—the integration of software and hardware to provide a resistance that adjusts in real time and in response to the individual’s volitional force within and between repetitions. The aim of the current paper is to expand this discussion and explain the potential for CARE technology to improve the delivery of eccentric resistance exercise in various settings. First, we overview existing resistance exercise equipment and highlight its limitations for delivering eccentric resistance exercise. Second, we describe CARE and explain how it can accomplish accentuated eccentric and eccentric-only resistance exercise in a new way. We supplement this discussion with preliminary data collected with CARE technology in laboratory and non-laboratory environments. Finally, we discuss the potential for CARE technology to deliver eccentric resistance exercise for various purposes, e.g., research studies, rehabilitation programs, and home-based or telehealth interventions. Overall, CARE technology appears to permit completion of eccentric resistance exercise feasibly in both laboratory and non-laboratory environments and thus has implications for researchers and practitioners in the fields of sports medicine, physiotherapy, exercise physiology, and strength and conditioning. Nevertheless, formal investigations into the impact of CARE technology on participation in eccentric resistance exercise and clinical outcomes are still required.
Supplementary Information
The online version contains supplementary material available at 10.1007/s40279-023-01842-z.
... Constant resistance is defined as a constant external load throughout the range of motion; regulated resistance is defined as a constant velocity load that provides a controlled speed throughout the range of motion; whereas fluid-based resistance is similar to regulated and variable resistance and has two types: hydraulic resistance and pneumatic resistance (McMaster et al., 2009). Variable resistance is defined as the type of resistance that changes during exercise (Frost et al., 2010). ...
... Research has demonstrated the feasibility of using kinetic data as real-time feedback information to athletes and for monitoring purposes, e.g., velocity-based resistance training uses movement speed values fed by linear sensors to keep athletes moving in specific speed intervals as much as possible to achieve training objectives (Jovanović and Flanagan, 2014). Power was assumed to be better indicator of the difference in explosive power between the two groups of athletes than speed in previous studies comparing free weight resistance with pneumatic resistance: whether monitored for a single training movement or the entire intervention (Frost et al., 2010;Franchini et al., 2011;Frost et al., 2016). In this study, power was chosen as the indicator for real-time feedback information and monitoring. ...
... 2. The downward pull of the air pressure on the light barbell is the primary source of load during squatting with pneumatic resistance. This downward pull counteracts the effects of inertia and momentum in the squatting process, resulting in a consistently high level of muscle effort throughout the centripetal phase of the squat (i.e., the muscle effort required in the second half of the squatting process is not significantly reduced by the increases in inertia and momentum) (Frost et al., 2010). Thus, the decreasing magnitude of inertia and momentum caused the difference in power output between the two groups during the centripetal phase. ...
Objective: The present study compared the effects of two different resistance types (pneumatic resistance and free weight) of 6-week squat training on the performance for young female judo athletes in linear speed and vertical jump by utilizing the maximum power of each set of squats in each training session as the monitoring vehicle. Monitoring data were used to assess the effects and trends of the two resistance types on 70% 1RM weight-bearing during the 6-week intervention training.
Methods: In a 6 weeks squat training (2 reps/week with a constant load), 23 adolescent female judo athletes (Age span: 13–16 years, 14.58 ± 0.96) were randomly selected and then divided into the traditional barbell (FW) group (n = 12) and the pneumatic resistance (PN) (n = 11) group according to different resistance types (free weight and pneumatic resistance), with 10 in FW group and 9 in PN group actually completed the study. Before and after training, the 30-m Sprint time (T-30M), vertical jump height and relative power (countermovement jump, static-squat jump, and drop jump), reactive strength index (DJ-RSI), and maximal strength were assessed. One-Way ANOVA was used to examine the pre-test differences of groups (FW and PN). A 2-factor mixed-model analysis of variance was used to examine the independent effects of group (FW and PN) and time (pre and post) on each dependent measure. Scheffe post hoc comparisons were used to examine the differences. Pre- and post-experimental differences between the two groups were analyzed using independent samples t-tests and magnitude-based inferences (MBI) derived from their p values, and effect statistics were applied to compare the pre- and post-changes exhibited by each group to identify the potential beneficiary groups.
Results: The PN group outperformed the FW group in terms of maximal power output per training session (822.5 ± 55.22 vs. 927.42 ± 48.15, conventional vs. pneumatic, p < 0.001, effect size = −2.02). After 6 weeks of training, the FW group showed significant increases in vertical jump height and relative strength (CMJ, SJ, DJ), with no significant gains observed in T-30 and maximal strength. The PN group showed significant improvements in maximal strength; however, no significant improvements were observed in the other tests. In addition, there was no significant difference in DJ-RSI between the two groups before and after training.
Discussion: At 70% weight bearing, free weight resistance appears to be more conducive to vertical jump growth, while pneumatic resistance appears to be more conducive to maximal strength gains; however, the maximal strength gains from pneumatic resistance may not be well applied to athletic performance. In addition, the body adapts more quickly to pneumatic resistance than to free weight resistance.
... The type of device or resistance will impact on the way muscles are activated and consequently influence on the induced training outcomes [65]. Although a detailed description of the type of resistance used in strength training is beyond the scope of this chapter based on the nature of the acting forces on the musculoskeletal system, five groups of resistances can be identified: ...
... 2. Variable gravitational-based resistance: Lever-arm-based systems or CAMs [56]. 3. Accommodating resistance: including two technologies systems (1) Isokinetic in which the movement velocity is controlled while the applied force changes over the range of motion at a relatively constant velocity [65] and (2) Isotonic that controls the force and measures changes in movement velocity over a range of motion at a constant force. 4. Nongravitational resistance: vibration machines [66] and rotary inertial machines (flywheel-based equipment) [67]. 5. Combining different mode of resistances: (1) hydraulic and pneumatic-based equipment which combines nongravity with accommodating resistance [65] (2) simple pieces of equipment such as bands, springs that combine non-gravity with progressive resistance [68] or chains that use gravity while is applied progressively [69]. ...
... 3. Accommodating resistance: including two technologies systems (1) Isokinetic in which the movement velocity is controlled while the applied force changes over the range of motion at a relatively constant velocity [65] and (2) Isotonic that controls the force and measures changes in movement velocity over a range of motion at a constant force. 4. Nongravitational resistance: vibration machines [66] and rotary inertial machines (flywheel-based equipment) [67]. 5. Combining different mode of resistances: (1) hydraulic and pneumatic-based equipment which combines nongravity with accommodating resistance [65] (2) simple pieces of equipment such as bands, springs that combine non-gravity with progressive resistance [68] or chains that use gravity while is applied progressively [69]. ...
Resistance training (RT) configures a specialized method of training that involves the progressive use of a wide range of resistive loads, different rate of muscle activation or movement velocities, and a variety of training modalities. RT is currently considered essential in athletic preparation. It is a key component for optimizing growth and maturation in children, promoting health and quality of life in the elderly, or to attenuate the incidence of injuries in physically active populations. Qualified professionals are necessary to design individualized RT programs for athletes from varying disciplines with very specific performance outcomes. The professional must consider specific needs for all ages, not only the athletic population, making the necessary adaptation to meet their level of ability and desired outcomes. Effective training stimuli should help increase performance and avoid overtraining. This is accomplished by manipulating physiological, neurological, and biomechanical-related variables. There is hard science behind the importance of menstrual cycle-based periodization, and—although research in this area is scarce—results suggest that designing training programs integrating the menstrual cycle hormonal fluctuation or the ingestion of triphasic contraceptives might be of relevance to optimize performance in premenopausal women.
... Resistance training has been widely used to improve strength, speed, and power in athletes, which are the main determinants of most sports that involve jumping, sprinting, and change of direction (Suchomel et al., 2018;Suchomel, Nimphius & Stone, 2016). Traditional resistance training, which employs isoinertial training, is known as constant resistance training (CRT) (Frost, Cronin & Newton, 2010). Specifically, the load lifted by an individual is constant in the range of motion. ...
... The defining characteristics of VRT include the provision of unloading where muscle force production is compromised and overloading where muscle force production is the greatest (Fleck & Kraemer, 2014). Anecdotal evidence of VRT dates back to the 1900s, when new training devices, such as cams, were developed in an attempt to combat the mechanical disadvantages associated with CRT (Frost, Cronin & Newton, 2010). However, some limitations that restrict the use of cams include the capital outlay on the device (Haff, 2000) and difficulty in combining cams with free weights (McMaster, Cronin & McGuigan, 2009). ...
... Similar to the force outcome results, evidence supporting improved velocity and power while performing VRT is also disputed (Galpin et al., 2015;Swinton et al., 2011). In particular, these inconsistent results can be attributed to the different VRT design methodologies used, including the method of equating the loading schemes (e.g., whether the relative loading is equated between VRT and CRT), the contribution of variable resistance (i.e., how much of the loading is coming from the elastic bands or chains), and variable resistance equipment differences (the training stimuli is governed by the inertial properties of these two equipment (Arandjelovic, 2010;Frost, Cronin & Newton, 2010)). For example, VRT using a relatively higher loading scheme (i.e., the loading at the bottom position is equal between VRT and CRT) significantly decreased peak velocity compared to CRT (Saeterbakken, Andersen & Van den Tillaar, 2016;Stevenson et al., 2010), some studies found that VRT using a relatively lower loading scheme (i.e., the loading at the top position is equal) increased peak and mean velocity compared to CRT (Baker & Newton, 2009;Heelas, Theis & Hughes, 2021). ...
Objective:
Acute effects of variable resistance training (VRT) and constant resistance training (CRT) on neuromuscular performance are still equivocal. We aimed to determine the differences between VRT and CRT in terms of force, velocity, and power outcomes.
Methods:
We searched PubMed, Web of Science, and SPORTDiscus electronic databases for articles until June 2021. Crossover design studies comparing force, velocity, and power outcomes while performing VRT and CRT were included. Two reviewers independently applied the modified version of the Cochrane Collaboration's tool to assess the risk of bias. A three-level random effects meta-analyses and meta-regressions were used to compute standardized mean differences (SMDs) and 95% confidence intervals.
Results:
We included 16 studies with 207 participants in the quantitative synthesis. Based on the pooled results, VRT generated greater mean velocity (SMD = 0.675; moderate Grading of Recommendations Assessment, Development and Evaluation (GRADE) quality evidence) and mean power (SMD = 1.022; low) than CRT. Subgroup analyses revealed that VRT considerably increased the mean velocity (SMD = 0.903; moderate) and mean power (SMD = 1.456; moderate) in the equated loading scheme and the mean velocity (SMD = 0.712; low) in the CRT higher loading scheme. However, VRT marginally significantly reduced peak velocity (SMD = -0.481; low) in the VRT higher loading scheme. Based on the meta-regression analysis, it was found that mean power (p = 0.014-0.043) was positively moderated by the contribution of variable resistance and peak velocity (p = 0.018) and peak power (p = 0.001-0.004) and RFD (p = 0.003) were positively moderated by variable resistance equipment, favoring elastic bands.
Conclusions:
VRT provides practitioners with the means of emphasizing specific force, velocity, and power outcomes. Different strategies should be considered in context of an individual's needs. Systematic review registration: PROSPERO CRD42021259205.
... However, constant resistance training (CRT) may not be the most conducive means to elicit maximal musculature activation as a result of mechanical disadvantages at specific joint angles (Kompf and Arandjelović, 2016). Alternatively, variable resistance training (VRT) where elastic bands are combined with free weights can vary the external load across the entire range of motion (Frost et al., 2010). Such a loading pattern is considered to greatly accommodate the exercises with an ascending strength curve, such as the back squat (Wallace et al., 2018). ...
... Furthermore, the findings with respect to power performance are also equivocal. Despite some studies supposing the superiority of VRT in terms of velocity-specific adaptation (Frost et al., 2010;Wallace et al., 2018), several studies have shown no significant differences between VRT and CRT (Andersen et al., 2015;Ataee et al., 2014;Katushabe and Kramer, 2020). The lack of powerful tasks within the intervention may result in the unchanged power outcomes. ...
... However, to date, research examining the long-term effect of complex training using VRT is scant and warrants further investigation. Previous research has utilized different VRT methodologies, and understanding acute neuromuscular responses may provide insight into how to most effectively manipulate VRT strategies (Frost et al., 2010). Andersen et al. (2016) found that a high contribution of variable resistance (81% of the total load) produced higher muscle activity compared to a medium contribution of variable resistance (49% of the total load). ...
The aim of this study was to investigate the differences in neuromuscular performance between variable resistance training and constant resistance training within complex training. Twenty-one well-trained collegiate basketball players were randomly assigned to either an experimental group (variable resistance training) or a control group (constant resistance training) and completed a twice weekly training program over an 8-week period. Training programs were the same except that the experimental group included variable resistance via elastic bands (40% of the total load). Maximum strength, vertical jump, horizontal jump, and sprint performance were assessed pre-and post-intervention. Both groups demonstrated significant increases in the back squat 1RM (experimental group +36.5% and control group +32.3%, both p < 0.001), countermovement jump (experimental group +12.9%, p = 0.002 and control group +5.6%, p = 0.02), and squat jump performance (experimental group +21.4% and control group +12.9%, both p < 0.001), whereas standing broad jump performance improved only in the experimental group (+2.9%, p = 0.029). Additionally, the experimental group showed significant improvement in the squat jump (p = 0.014) compared with the control group. However, no statistically significant differences were found between groups for countermovement jump (p = 0.06) and sprint performance at 10 m (p = 0.153) and 20 m (p = 0.076). We may conclude that both training modalities showed similar improvements in maximum strength. Performing variable resistance training within a complex training program is more efficient to enhance selective power performance in well-trained collegiate basketball players.
... Further power development, therefore, 96 typically requires the inclusion of additional lighter (e.g., 30-60% (1RM), more mechanically specific 97 training methods that optimize movement velocity as dictated by the force-velocity-power 98 relationship (9,10,27). In practice, methods to implement these faster velocity-type adaptations 99 usually include ballistic (e.g., jump squat) or explosive non-ballistic (e.g., 'speed' back squat) exercises, 100 with the main biomechanical difference being the projection of the body, system or object into free 101 space during the ballistic task (14). However, comparisons of the underpinning mechanical demands 102 of both training strategies are limited yet are vital for practitioners to make informed programming 103 decisions. ...
... Ballistic exercises typically produce higher mechanical outputs than their non-ballistic counterparts as 114 they exhibit a longer period of positive acceleration (displacement minima to velocity maxima), 115 referred to as the 'propulsion sub-phase' (8,14,26). As a result, when compared with non-ballistic 116 equivalents, ballistic exercises exhibit higher velocities and larger forces, power and muscle activity, 117 often making them the preferred choice for S&C coaches when designing 'power-type' training blocks 118 (6,11,23,26,31). ...
... Significantly more power 313 (6,35), higher velocities (6,23,35), larger forces (35) and displacements (35) have previously been 314reported across multiple loads (0-85% 1RM) in the free-weight jump squat compared to the back squat 315 when calculated over the full concentric phase(8). As ballistic exercise is accelerative, of high velocity 316 and culminates in the projection of the body, system or projectile into free space, there is a reduced 317 requirement to perform negative acceleration at the end of the concentric phase in comparison to 318 non-ballistic exercise(14). Further, this period of negative acceleration has been reported to 319 contribute from 21.9-47.7% of the concentric phase when performed across incremental loads (15-320 90% 1RM) in the free-weight bench press(15,23). This sub-phase, therefore, has been offered as a 321 reason for non-ballistic exercises having limited application when performed with maximal intent 322 under submaximal loading, particularly for the purpose of increasing force, velocity, power or impulse 323(6,31). ...
The study aim was to compare kinetics and kinematics of two, lower-body free-weight exercises, calculated from concentric and propulsion sub-phases, across multiple loads. Sixteen strength trained men performed back squat one-repetition maximum tests (1RM) (visit 1), followed by two incremental back squat and jump squat protocols (visit 2) (loads = 0% and 30-60%, back squat 1RM). Concentric and propulsion phase force-time-displacement characteristics were derived from force-plate-data and compared via analysis of variance and Hedges g effect sizes. Intra-session reliability was calculated via intraclass correlation coefficient (ICC) and coefficient of variation (CV). All dependent variables met acceptable reliability (ICC > 0.7; CV < 10%). Statistically significant three-way interactions (load phase exercise) and two-way main effects (phase exercise) were observed for mean force, velocity (30-60% 1RM), power, work, displacement, and duration (0%, 30-50% 1RM) (p < 0.05). A significant two-way interaction (load exercise) was observed for impulse (p < 0.001). Jump squat velocity (g = 0.94-3.80), impulse (g = 1.98-3.21), power (g = 0.84-2.93) and work (g = 1.09-3.56) were significantly larger across concentric and propulsion phases, as well as mean propulsion force (g = 0.30-1.06) performed over all loads (p < 0.001). No statistically significant differences were observed for mean concentric force. Statistically longer durations (g = 0.38-1.54) and larger displacements (g = 2.03-4.40) were evident for all loads and both sub-phases (p < 0.05). Ballistic, lower-body exercise produces greater kinetic and kinematic outputs than non-ballistic equivalents, irrespective of phase determination. Practitioners should therefore utilize ballistic methods when prescribing or testing lower-body exercises to maximize athlete’s force-time-displacement characteristics.
... The resistance-training volume is defined as the measure of the total amount of work carried out in a single training session or summed over weeks or months of training [5]. Work is the result of the multiplication of the total bouts of force exerted to displace a mass or exercise bar/platform to a certain distance [6,7]. In general, calculating the volume in programs focused on muscle hypertrophy is an attempt to quantify the external work carried out to then estimate the dose of stimulus imposed on targeted muscles [7][8][9][10][11][12][13]. With the advantage of portable technologies, the biomechanical outcomes to assess training work can be reliably estimated [14][15][16]; however, to assess them in a real-world setting is recognized to be difficult, even in laboratories [6]. ...
... Work is the result of the multiplication of the total bouts of force exerted to displace a mass or exercise bar/platform to a certain distance [6,7]. In general, calculating the volume in programs focused on muscle hypertrophy is an attempt to quantify the external work carried out to then estimate the dose of stimulus imposed on targeted muscles [7][8][9][10][11][12][13]. With the advantage of portable technologies, the biomechanical outcomes to assess training work can be reliably estimated [14][15][16]; however, to assess them in a real-world setting is recognized to be difficult, even in laboratories [6]. Therefore, probably for this reason, in the resistance-training literature, the volume is mostly expressed using parameters that directly affect training work [5][6][7], such as the number of sets, repetitions, and volumeload (sets*repetitions*load [kg]) [7][8][9]. ...
... In general, calculating the volume in programs focused on muscle hypertrophy is an attempt to quantify the external work carried out to then estimate the dose of stimulus imposed on targeted muscles [7][8][9][10][11][12][13]. With the advantage of portable technologies, the biomechanical outcomes to assess training work can be reliably estimated [14][15][16]; however, to assess them in a real-world setting is recognized to be difficult, even in laboratories [6]. Therefore, probably for this reason, in the resistance-training literature, the volume is mostly expressed using parameters that directly affect training work [5][6][7], such as the number of sets, repetitions, and volumeload (sets*repetitions*load [kg]) [7][8][9]. With that, it is easier to calculate the training volume and then to organize the prescription of training programs [7][8][9]. ...
Calculating resistance-training volume in programs focused on muscle hypertrophy is an attempt to quantify the external workload carried out, then to estimate the dose of stimulus imposed on targeted muscles. The volume is usually expressed in some variables that directly affected the total training work, such as the number of sets, repetitions, and volume-load. These variables are used to try to quantify the training work easily, for the subsequent organization and prescription of training programs. One of the main uses of measures of volume quantification is seen in studies in which the purpose is to compare the effects of different training protocols on muscle growth in a volume-equated format. However, it seems that not all measures of volume are always appropriate for equating training protocols. In the current paper, it is discussed what training volume is and the potentials and shortcomings of each one of the most common ways to equate it between groups depending on the independent variable to be compared (e.g., weekly frequency, intensity of load, and advanced techniques).
... Au cours de ces mouvements, le déplacement de la charge est stoppé à la fin de l'amplitude disponible, sans projection de la masse totale. La condition balistique présente donc l'avantage de ne pas être limitée par le fait de devoir décélérer la charge à la fin du mouvement (Frost et al., 2010). En d'autres termes, la production de force intervient tout au long de l'amplitude du mouvement. ...
... Ces exercices semblent également pouvoir induire des adaptations neuromusculaires plus significatives que les exercices non balistiques (Cormie et al., 2011b). En effet, ils impliquent une vitesse, une force, une puissance et une activité musculaire plus importantes qu'en condition non balistique (Frost et al., 2010). ...
... Depuis plusieurs décennies, les effets de l'entraînement en force ont été largement décrits et ont révélé des effets bénéfiques sur la capacité de production de force maximale (Folland et Williams, 2007, Komi, 2003, Kraemer, 2005. Dans ce contexte, la modalité isoinertielle non-balistique présente un pattern mécanique qui est propice à la stimulation de la force maximale, notamment en début de mouvement (Frost et al., 2010). Cependant, les exercices et les charges utilisées dans cette modalité d'exercice impliquent des mouvements et des vitesses de contraction lentes qui ne respectent pas toujours le principe de spécificité de l'activité. ...
La capacité d’un athlète à accélérer un objet ou son propre corps constitue un déterminant essentiel de la performance sportive dans de nombreuses disciplines. Cette qualité d’explosivité est liée aux limites mécaniques du système neuromusculaire et notamment à la puissance maximale que l’athlète est capable de produire. L’évaluation précise de ce paramètre peut se révéler particulièrement intéressante pour les sportifs experts de disciplines nécessitant des qualités de puissance et d’explosivité. En effet, elle permet de mieux définir leur profil athlétique et d’individualiser la calibration des contenus d’entraînement musculaire. Ce travail se proposait d’explorer les liens possibles entre des indicateurs innovants de la fonction neuromusculaire et la performance explosive appréhendée au plus près des conditions de compétition.
Dans le cadre d’une première partie expérimentale, nos travaux ont d’abord consisté à évaluer la validité et la reproductibilité de méthodes de terrain communément utilisées pour déterminer les qualités de puissance dans un mouvement explosif : le squat jump. L’effet de la charge sur les coordinations musculaires impliquées lors de la réalisation de ce mouvement balistique ont ensuite été analysées afin d’étudier les facteurs nerveux de la production d’un mouvement explosif. Les méthodes validées dans la première étude nous ont ensuite permis de montrer que les relations force-vitesse étaient dépendantes de l’activité sportive. Ces profils n’étaient par ailleurs pas systématiquement optimisés chez des sportifs très entraînés. La deuxième partie expérimentale a consisté à appliquer ces méthodes d’évaluation innovantes à l’étude de l’escrime. Dans un premier temps, les patterns mécaniques et neuromusculaires ont été décrits lors d’un assaut spécifique (i.e. marché-fente), mettant en évidence l’importance de la capacité à produire des niveaux de force élevés, notamment avec la jambe arrière, dans des mouvements exécutés à vitesse élevée. Les relations entre les profils force-puissance-vitesse optimaux, et les déterminants de la performance en escrime ont ensuite été identifiés, afin de vérifier la pertinence d’évaluer ces paramètres innovants dans cette discipline explosive. Enfin, les derniers travaux n’ont pas montré d'effet d’un entraînement musculaire balistique, calibré à partir des profils force- et puissance-vitesse des escrimeurs. Les résultats de cette étude préliminaire ouvrent toutefois des perspectives de recherche intéressantes, qui permettraient de mieux comprendre l’impact des adaptations neuromusculaires sur la performance explosive.
... The advantages of SSC augmentation on the subsequent concentric phase have been well documented [57,68], such as increased average velocity and power and higher peak force and acceleration. Interestingly, the exact mechanism of the augmentation remains uncertain [68,69]. ...
... The advantages of SSC augmentation on the subsequent concentric phase have been well documented [57,68], such as increased average velocity and power and higher peak force and acceleration. Interestingly, the exact mechanism of the augmentation remains uncertain [68,69]. Current hypotheses include increased time for force development, strain energy storage in the series elastic muscle-tendon components, heightened levels of muscle activation, and evoking of stretch reflexes [64,[69][70][71][72]. ...
... Current hypotheses include increased time for force development, strain energy storage in the series elastic muscle-tendon components, heightened levels of muscle activation, and evoking of stretch reflexes [64,[69][70][71][72]. A full examination of the research supporting each of these explanations is beyond the scope of this chapter; however, interested readers may refer to several papers dedicated to this topic [57,68,69,72]. Important for the practitioner to understand is that SSC augmentation is related to the stretch magnitude, rate, and duration of the stretch [53,57,63,[69][70][71]. ...
... The advantages of SSC augmentation on the subsequent concentric phase have been well documented [57,68], such as increased average velocity and power and higher peak force and acceleration. Interestingly, the exact mechanism of the augmentation remains uncertain [68,69]. ...
... The advantages of SSC augmentation on the subsequent concentric phase have been well documented [57,68], such as increased average velocity and power and higher peak force and acceleration. Interestingly, the exact mechanism of the augmentation remains uncertain [68,69]. Current hypotheses include increased time for force development, strain energy storage in the series elastic muscle-tendon components, heightened levels of muscle activation, and evoking of stretch reflexes [64,[69][70][71][72]. ...
... Current hypotheses include increased time for force development, strain energy storage in the series elastic muscle-tendon components, heightened levels of muscle activation, and evoking of stretch reflexes [64,[69][70][71][72]. A full examination of the research supporting each of these explanations is beyond the scope of this chapter; however, interested readers may refer to several papers dedicated to this topic [57,68,69,72]. Important for the practitioner to understand is that SSC augmentation is related to the stretch magnitude, rate, and duration of the stretch [53,57,63,[69][70][71]. ...
... His approach combines various forms of traditional resistance training with plyometric training, demonstrating its effectiveness in improving multiple physical health outcomes, including straight sprint speed, vertical jump height, and change of direction speed (CODS) (Thapa et al., 2024). The resistance training component of complex training primarily involves constant resistance, which can enhance athletic strength and power (Frost et al., 2010). In constant resistance training (CRT), the external load is typically maintained consistently throughout the range of motion. ...
... In this study, results showed that the VRT exhibited greater improvement in relative maximum punch force, punch power, and punch speed compared with the CRT. This may be because the variable resistance loads change the form of tension loading during CRT, allowing resistance adaption to leverage changes and thus reducing the mechanical disadvantages of specific angles on movement speed and providing compensatory acceleration (Frost et al., 2010). Furthermore, VRT produces a nonstable form that helps athletes enhance their capacity to tackle heavier loads, thus stimulating the neuromuscular system beyond CRT alone (Zimmermann et al., 2020). ...
Objectives
This study explored the effects of 6 weeks of variable resistance training (VRT) and constant resistance training (CRT) within complex training, on muscle strength and punch performance.
Methods
Twenty-four elite female boxers from the China National team were divided randomly between an experimental group (VRT) and a control group (CRT). Maximum strength of the upper and lower limbs, countermovement jump (CMJ) performance, and punch performance (single, 10s and 30s continuous) were assessed pre- and post- intervention.
Results
VRT and CRT showed significant increases (p < 0.001) in the bench press (ES = 1.79 and 1.07, respectively), squat (ES = 1.77 and 1.10, respectively), and CMJ (ES = 1.13 and 0.75, respectively). The bench press (p < 0.05) and squat (p < 0.05) improved significantly more following VRT compared to CRT. Additionally, single punch performance (speed, force, and power) increased significantly in the experimental group (ES = 1.17–1.79) and in the control group (ES = 0.58–1.32), except for the lead punch force in the control group (p > 0.05, ES = 0.20). 10s continuous punch performance (number, speed, force, and power) increased significantly (both p < 0.05) in the experimental group (ES = 0.52–1.65) and in the control group (ES = 0.32–0.81). 30s continuous punch performance (number, force, and power) increased significantly increased significantly (both p < 0.05). However, no statistically significant differences were found between groups for punch performance.
Conclusion
These findings provide evidence that VRT may improve maximum muscle strength in both upper and lower limbs, vertical jump and punch performance in elite amateur boxers.
... An increase in velocity would require an enhancement of the force while using the same load. Also, the joint angle is a factor determining the resistance that is applied to a muscle [52] and needs consideration. ...
... Firstly, it is questionable if they can always produce the overload needed for exercise-driven muscle changes [14]. Secondly, a disadvantage may be the necessity to overcome the elastic recoil in the movements' beginning [52]. Isokinetic training facilities regulate the movement velocity during exercise. ...
Bone metastasis (BM) is a complication in advanced cancer. Symptoms are pain, pathological fractures, hypercalcemia or spinal cord compression. Pain is experienced by 60–80% of patients and has a deteriorating effect on activities of daily life (ADL) and quality of life (QoL). Physical activity is an intervention recommended for early and advanced cancer patients. Resistance training (RT) offers different advantages for BM. It can improve muscle strength, bone density and QoL and prevent loss of functional activity. The question remains: how can RT be delivered in BM patients? Different approaches are possible: supervised in-patient and unsupervised training. Loading to BM sites may be avoided or implemented and certain precautions may be given. Various prerequisites are crucial before implementing RT in BM patient cohorts. This chapter will give an overview of the pathophysiology of BM and a description of various assessments. It will elaborate on the feasibility, safety and efficacy of different types of RT. It will investigate prescription details (intensity, exercise tools and additional requirements) to ensure safety.
... Additionally, intermittent and team sports are also benefited by resistance training due to the fact that increases in maximal muscle strength are strongly associated with improvements in muscle power (mechanical power = force × velocity) (Cormier et al., 2020(Cormier et al., , 2021. In conclusion, resistance training is capable of improving the different manifestations of strength; manipulating training variables is a key to reach the specific adaptation aimed at in distinct sports modalities (Frost et al., 2010). ...
... One of the disadvantages of traditional power training is the inability to maintain a constant torque during all phases of the movements, with some ranges of motion being more favourable to producing higher muscle torque. Typically, force and power output are reduced at the end of the concentric phase, which is considered a 'suboptimal' stimulus that could limit training responses (Anderson et al., 2008;Frost et al., 2010;Andersen et al., 2015). To circumvent this, variable resistance training has been proposed as a power training method that combines acceleration and higher load/torque during the whole range of motion by implementing chains or elastic bands to the barbell. ...
In strength and power sports, an optimal development of muscle strength, power, and speed, as well as optimal body composition, is key for performance and competitive success. Additionally, the ability to perform and sustain high-intensity exercise, either in a single bout or in multiple bouts separated by short resting intervals, is also determinant to success in a wide variety of strength and power sports. The optimal development of these capacities depends on multiple factors, with adequate training stimuli and nutritional support being two cornerstones to success. This article presents an overview of the physiology underpinning high-intensity, short-duration exercises, and discusses training methods for developing muscle strength and power, and for promoting muscle growth. Nutritional strategies, as well as supplements to aid training performance, recovery, and competition performance are discussed, with focus on high-intensity exercises, strength, and power sports.
... For example, the results from AEL with resistance bands may be influenced by the changes in band tension which is greatest at the top and decreases throughout the eccentric phase before the bands are released. 11,24 Thus, resistance banded AEL can be difficult to compare across exercises with varied movement lengths (i.e., drop jump v. countermovement jump) and to fixed loading strategies (i.e., dumbbell or barbell). Since research of AEL during jumping tasks is limited, 11 and in support of recent literature review conclusions, 9 continued research is warranted to investigate employing AEL with increased eccentric and concentric loads during jumping-based movements. ...
... It is also important to consider the use of band tension during depth jumps as the tension will be greatly reduced as the individual drops from the box through the landing phase. 11,24 Further, previous AEL research conducted with fixed dumbbell loads and elastic resistance bands incorporated full release of the weights/bands upon the concentric portion of the jump, and allowed the subjects to swing their arms upward after release. 16,[21][22][23] In contrast, by utilizing a barbell and trap bar in our study, weight was never fully released by the subjects as they had to jump with the bars which eliminated arm swing. ...
This study examined effects of accentuated eccentric loading (AEL) on barbell and trap bar loaded countermovement jumps (LCMJ). Twenty-one subjects (16 male, 5 female; Age: 23.5 ± 1.8 years; Body mass: 81.4 ± 10.6 kg; Height: 176.9 ± 7.2 cm; Training age: 7.1 ± 2.6 years) participated in this study. Upon establishing one repetition maximum and baseline jumping conditions, three experimental loading sessions were completed in random order. Barbell and trap bar LCMJ were performed with a spectrum of fixed loads from 20-50 kg during control conditions and with additional AEL loads of 10, 20, or 30 kg for experimental conditions. According to coefficients of variation (<10%), jump height, modified reactive strength index (mRSI), force, impulse, and duration measures were considered reliable across conditions. Mixed effect models analyzed effects of AEL against fixed loading in trap bar and barbell LCMJ (p < 0.05). Compared to the control condition, AEL produced negligible reductions in jump height during barbell LCMJ and small reductions during trap bar LCMJ. Modified reactive strength indexes were reduced by AEL during barbell LCMJ but not trap bar LCMJ. Average braking forces were greater in AEL conditions, while propulsive impulse was lower in the AEL conditions. The barbell LCMJ with AEL resulted in longer propulsive durations and unchanged braking durations, while propulsive and braking durations were lower during trap bar LCMJ with AEL compared to control conditions. This investigation revealed that use of AEL increases eccentric braking forces but decreases propulsive phase outputs, which subsequently may result in negligible to small acute decreases in LCMJ height. Implementing AEL during LCMJ may be an effective strategy to improve deceleration / eccentric abilities. Future research should explore longitudinal power and deceleration adaptations, while concomitantly improving acutely altered movement mechanics from AEL.
... The fixed seated position and back support is associated with higher degree of safety and lower technical demands when compared to free weight exercises. In addition, pneumatic-based resistance produces flatter force curves compared to free weighs, attenuating the high forces needed to overcome inertia in mass-based exercises (10). The lower strain on the musculoskeletal system may further reduce risk of injury and recovery time. ...
... Estimation of 1RM from the L-V relationship is typically based on given threshold velocity (TV) (e.g., 2,10,11,19). Because no previous studies have calculated TV for 1RM testing in 1RM prediction of lower-limb strength tests 7 the Keiser A420 aparatus (TV is highly exercise specific), a mean TV value of 0.23 m·s -1 derived from preliminary pilot testing was applied. ...
The aim of this study was to explore the reliability and validity of different lower-limb strength tests to determine the one-repetition maximum (1RM) value in the Keiser A300 leg press. Twenty-eight recreationally active subjects performed load-velocity (L-V) relationship, 1RM, isometric midthigh pull (IMTP), and maximal repetitions to failure (MRF) tests on three separated sessions. Predicted 1RMs for the L-V relationship were estimated from a linear regression equation, correlating movement velocity and relative loads. Number of repetitions from the MRF tests (at loads relative to bodyweight) and peak force from the IMTP tests were used in regression equations to predict 1RM. The level of significance was set to ρ ≤ 0.05. All 1RM prediction methods were highly comparable to the traditional 1RM test, as only trivial and non-significant differences were observed. Furthermore, the L-V relationship was the most reliable (intraclass correlation coefficient [± 95%CI] = 0.99 [0.98-0.996]; effect size =-0.01 [-0.38, 0.36], standard error of the measurement = 6.4 kg; coefficient of variation = 3.0 [2.2-3.8]% and valid (r = 0.95 [0.89-0.98], effect size = 0.08 [-0.29, 0.45], standard error of the 1RM prediction of lower-limb strength tests 2 estimate = 20.4 kg; coefficient of variation = 7.4 [5.5-9.3]%) when compared to direct 1RM measurements. The L-V relationship test showed a significant change score relationship (r = 0.41 [0.04, 0.68]) against the direct 1RM measurements. In conclusion, the tests used in this study cannot be used interchangeably, but they represent a good alternative in training settings where 1RM testing is not feasible.
... Constant external resistance (CR) is the most commonly used resistance mode for inducing musculoskeletal adaptation and is characterized by exercise in which the total resistance depends on the mass of the object to be lifted (Frost et al., 2010), demanding uniform resistance to the muscles and joints, despite the considerable strength of muscle changes throughout this range of motion (ROM). Alternatively, accommodating resistance (AR) (i.e., elastic bands [EBs] or chains attached to the barbell) has been used to provide variation in the resistance (load) throughout the ROM when performing movement (McMaster et al., 2009) by overcoming the mechanical disadvantages related to specific joint angles during exercise (Ebben & Jensen., 2002;Smith et al., 2019;Wallace et al., 2006). ...
... In addition, the load is being lifted due to the coefficient of elasticity; thus, the force required to elicit movement proportionally increases with the amount of band deformation. Therefore, EB can increase the tension as the joint angle becomes more advantageous (Frost et al., 2010). Hence, EB has been shown to augment the range of the concentric portion of exercise in which the barbell is accelerated and therefore cope with deceleration at the end of the concentric phase of the lift, during which the skeletal muscles are not optimally contracting because the lifter unintentionally decelerated the barbell (García-López et al. , 2016). ...
Purpose: This study aimed to compare the effects of free-weight resistance with and without elastic band (EB) tension on upper-body maximal strength and strength endurance during bench press (BP) exercise.
Methods: Twenty-six trained males (age: 26 ± 2.4 years; body mass: 73 ± 7.6 kg; stature: 172 ± 5.8 cm) were randomly assigned to two groups, CON (n = 13) and EXP (n = 13). BP sessions were performed twice weekly over 12 weeks. Both groups followed the same training program except that the EXP group executed BP with 30% of the prescribed load originating from the use of EB. BP one repetition maximum (1RM) and the maximum number of repetitions (MNR) for muscular fatigue were tested before and after the intervention.
Results: Analysis of covariance with the pretest value as the covariate revealed that both the CON and EXP groups demonstrated improvements in maximal strength and muscular endurance. However, the EXP group exhibited significantly greater improvements in 1RM (14% vs. 12%) and MNR (27% vs. 7%).
Conclusion: A combination of free-weight and elastic bands may provide a greater training stimulus than free-weight resistance alone to improve upper-body strength and muscular endurance in trained adult men.
... Resistance bands have been used during AEL to provide resistance during the eccentric phase of a countermovement jump and drop jump [102,103]. This method would accelerate an individual's mass faster during the eccentric phase than weighted AEL [104], with the aim of accelerating an athlete incorporating the velocity measure in the force-velocity curve [34]. Therefore, it is recommended that if bands are used instead of increasing mass during AEL, then the term 'accelerated eccentric loading' (ACEL) should be used as this gives further credence to the training method. ...
... Additionally, during accelerated eccentric motions, mass travels at a greater velocity. If two objects are the same mass and travel the same displacement, if one has a greater acceleration, then momentum will increase, so a greater impulse (impulse = force × ∆time) is required to stop the mass in motion [104]. This was shown by Van den Tillaar [43], who identified that, when participants performed back squats with different eccentric execution velocities, faster eccentric actions achieved the greatest force as the two faster velocities achieved a greater peak force during the lowest displacement (bottom) of a back squat [7]. ...
Eccentric training as a method to enhance athletic performance is a topic of increasing interest to both practitioners and researchers. However, data regarding the effects of performing the eccentric actions of an exercise at increased velocities are limited. This narrative review aimed to provide greater clarity for eccentric methods and classification with regard to temporal phases of exercises. Between March and April 2021, we used key terms to search the PubMed, SPORTDiscus, and Google Scholar databases within the years 1950–2021. Search terms included ‘fast eccentric’, ‘fast velocity eccentric’, ‘dynamic eccentric’, ‘accentuated eccentric loading’, and ‘isokinetic eccentric’, analysing both the acute and the chronic effects of accelerated eccentric training in human participants. Review of the 26 studies that met the inclusion criteria identified that completing eccentric tempos of < 2 s increased subsequent concentric one repetition maximum performance, velocity, and power compared with > 4 s tempos. Tempos of > 4 s duration increased time under tension (TUT), whereas reduced tempos allowed for greater volume to be completed. Greater TUT led to larger accumulation of blood lactate, growth hormone, and testosterone when volume was matched to that of the reduced tempos. Overall, evidence supports eccentric actions of < 2 s duration to improve subsequent concentric performance. There is no clear difference between using eccentric tempos of 2–6 s if the aim is to increase hypertrophic response and strength. Future research should analyse the performance of eccentric actions at greater velocities or reduced time durations to determine more factors such as strength response. Tempo studies should aim to complete the same TUT for protocols to determine measures for hypertrophic response.
... 16,31 This observation can be utilised with that of PAPE and the incorporation of resistance bands. Resistance bands would allow for an increase in acceleration because they apply the mass of interest with an additional force (Fapplied = Fmass + Fband), 1,14 where Fmass ...
... is the mass of the object that is applied by gravity (ie, barbell load) and Fband is the load that is applied by the bands. 1,14 The incorporation of bands could result in less load being needed, so that PAPE could be achieved among athletes; however, band tension is difficult to quantify, and a practitioner would need a suitable place to anchor the bands. Therefore, more research regarding PAPE protocols using resistance bands is warranted before a conclusion can be made. ...
Post-activation performance enhancement (PAPE) can be used in jump performance. This review recommends that PAPE be subcategorised into two groups: training PAPE and performance PAPE. Training PAPE methods can be incorporated for training purposes where more select equipment, time, and space is available. Performance PAPE can be utilised to enhance competition performance in which limited, or no equipment, is required and can be easily performed before an event. The authors found that isoinertial methods are commonly employed for both performance and training PAPE; however, plyometric training appears a more favourable form of performance PAPE. Furthermore, accentuated eccentric loading could be coupled with plyometric training to achieve the highest PAPE response, but further work is required.
... 10,14 Preferably, the FV profile should include measurements close to both F 0 and V 0 , as previous studies have shown that extensive extrapolation of the regression line may lead to inaccuracies in estimations of F 0 and V 0 , which in turn affects the reliability and validity of the S FV and P max . 15,16 The pneumatic resistance-based Keiser leg press (utilizing air pressure as a means of resistance 17 ) is a commercial device available in many sports and research facilities all over the world (applied in over 30 original, peer-reviewed papers the last 4 y). 5,[18][19][20][21][22] Compared with weight-based exercises, the resistance from the pneumatic leg press is minimally influenced by inertia and bodyweight. ...
... 10,22 The pneumatic device measures compression forces of the piston in the air cylinder. 17 This measurement of force is arguably less direct than other approaches such as reaction forces obtained with force plates, which are commonly considered gold standard for force measurements during ballistic movements. 23 For athletes and coaches, it is imperative to know whether values obtained from testing are accurate, and how these values can be interpreted, for example, compared with force plate data. ...
Purpose:
The aim of this study was to examine the concurrent validity of force-velocity (FV) variables assessed across 5 Keiser leg press devices.
Methods:
A linear encoder and 2 independent force plates (MuscleLab devices) were mounted on each of the 5 leg press devices. A total of 997 leg press executions, covering a wide range of forces and velocities, were performed by 14 participants (29 [7] y, 181 [5] cm, 82 [8] kg) across the 5 devices. Average and peak force, velocity, and power values were collected simultaneously from the Keiser and MuscleLab devices for each repetition. Individual FV profiles were fitted to each participant from peak and average force and velocity measurements. Theoretical maximal force, velocity, and power were deduced from the FV relationship.
Results:
Average and peak force and velocity had a coefficient of variation of 1.5% to 8.6%, near-perfect correlations (.994-.999), and a systematic bias of 0.7% to 7.1% when compared with reference measurements. Average and peak power showed larger coefficient of variations (11.6% and 17.2%), despite excellent correlations (.977 and .952), and trivial to small biases (3.9% and 8.4%). Extrapolated FV variables showed near-perfect correlations (.983-.997) with trivial to small biases (1.4%-11.2%) and a coefficient of variation of 1.4% to 5.9%.
Conclusions:
The Keiser leg press device can obtain valid measurements over a wide range of forces and velocities across different devices. To accurately measure power, theoretical maximal power calculated from the FV profile is recommended over average and peak power values from single repetitions, due to the lower random error observed for theoretical maximal power.
... he development of high-power values through the action of the neuromuscular system is considered a primary objective to improve performance in various sports practices [1,2,3]. This capacity is usually estimated indirectly by the height reached in vertical jumps [4,5,6,7,8,9,10,11,12,13]. ...
... The studies of vertical jumps with added load allow to evaluate changes in the force-velocity and power-velocity curves and, therefore, contribute to a better understanding of the relationships between the action of the neuromuscular system and the mechanical properties and functional performance on sports [22,23,24,25,26]. External load inevitably affects the kinematic pattern and the overall efficiency of the muscular system [1,23]. For example, the evidence suggests that the addition of loads of about 30% of body weight causes drastic changes in the jump pattern [10]. ...
The coordination between lower limb segments and power output developed during Squat Jumps in different load conditions was analyzed in ten trained male subjects (age 22.5±2.1 years; body height 176.5 ±5.4 cm; body mass 75.8 ±5.8; BMI 24.3± 1.8). We used a functional electromechanical dynamometer to control added load, 0% to 30% of body weight during the push-off phase. Significant differences between load conditions were evaluated by one-way repeated-measures ANOVA, p <0.05, for jump height, maximum vertical force, maximum vertical speed, and maximum angular speeds of the hip, knee and ankle. Pearson correlation coefficients were calculated to examine the relationships between jump height and the other variables. Angular velocities that presented significant differences between conditions were considered to analyze coordination through the graphs of the angular speed average values per condition during push-off phase. Power output decreased with the load and showed higher correlation with jump height at 30% load. This indicates that power training with SJ must be carried out without load, but to evaluate the power through the SJ height, a load of at least 30% should be used. Maximum articular velocities of hip and knee changed with increasing load and were correlated with height at 30% load. The final values and slope at the beginning of the push-off phase of relationship between hip and knee speed, indicate different coordination for 0% and load conditions and suggest a greater transfer from rotational to vertical speed in jumps without added load.
Keywords-Vertical jump, human coordination, performance evaluation.
... When performing an exercise with free weights, the maximal load lifted is often dictated by a short section within the range of motion (ROM) called the sticking region (van den Tillaar et al., 2014). Beyond the sticking region there will be a mismatch between the external torque and the potential of the muscular torque (Gabriel et al., 2006;Frost et al., 2010). That is, when you have crossed the sticking region, the lift becomes quite easy. ...
... That is, when you have crossed the sticking region, the lift becomes quite easy. In exercises with an ascending force curve such as deadlift, squat, and bench press, combining free weights and elastic bands have been proposed as an alternative to reduce this mismatch and therefore optimize the relationship between muscle-and free weight torque (Frost et al., 2010;Wallace et al., 2018). The elastic bands induce a variable resistance as they are stretched due to their elasticity (McMaster et al., 2010), eliciting increasing muscular demand throughout the ROM. ...
The aim of the study was to compare neuromuscular activation, kinetics and kinematics in three variations of the deadlift: (1) free weights, (2) free weights with elastic bands as resistance (bands anchored to the ground) and (3) free weights with elastic bands as assistance (bands attached above the bar). Sixteen resistance-trained men performed one repetition of the three variations as fast as possible using a 2-repetition maximum load in randomized and counterbalanced order. Muscle activation (gluteus maximus, semitendinosus, biceps femoris, erector spinae, vastus lateralis, and vastus medialis), kinematics (average-, peak-, and time to peak velocity), and kinetics (average-, peak,-and time to peak force) were measured during the ascending movement. Resisted and assisted deadlifts led to higher average and peak force outputs (p < 0.001–0.037, ES = 0.29–0.58), and time to peak velocity was shorter when compared to the free weights deadlift (p = 0.005–0.010, ES = 0.83–1.01). However, peak force was achieved faster when using free weights (p < 0.001, ES = 1.58–2.10) and assisted deadlifts had a lower peak velocity compared to resisted and free weights deadlift (p = 0.004–0.046, ES = 0.43–0.60). There were no significant differences in muscle activation between the different conditions (p = 0.082–1.000). In conclusion, the assisted and resisted deadlift produced higher force when compared to free weights. However, free weight and resisted deadlift seem more favorable for the barbell velocity. These findings are of importance for athletes and coaches which should select exercise depending on the goal of the session.
... The use of hydraulics could provide an alternative that enables affordable, yet consistent, precise and adjustable resistance force. 16 Although hydraulic-type resistance has been previously used for the purpose of strength training, 17,18 currently there are no hydraulic devices that allow the application of resistance while sprinting. Hydraulic knee extension resistance machines have been found to provide resistance force consistently and produce comparable forces to isokinetic devices. ...
The hydraulic resistance device (HRD), a state-of-the-art device developed primarily for resisted sprint training, lacks exploration of its force-generating properties. This technical note aims to evaluate these properties in vitro. In a laboratory experiment, the HRD was pulled with a motorised winch at four speeds (1–4 m s ⁻¹ ) and 12 different HRD resistance levels (low, medium and high). The resistance force induced by the HRD was measured using a force plate mounted under the device, and calculated as mean horizontal force produced at a constant pulling speed. Resistance force repeatability between pulling speeds at specific resistance levels was assessed using the coefficient of variation (CV) whereas the intraclass correlation coefficient (ICC 3,1 ) was calculated to determine the consistency. A linear regression model quantified resistance force as a function of HRD resistance level. Accuracy of the model was assessed using root mean square error (RMSE). Across 12 resistance levels, the HRD produced resistance forces ranging from 22.57 ± 4.84 to 164.57 ± 4.84 N. The CV decreased from 21.5% at the lowest resistance to 0.4% at the highest. The HRD produced resistance force with high consistency (ICC 3,1 CI = 0.990–0.999). The linear regression model showed a near-perfect fit ( R ² = 0.99) and predicted resistance force more accurately at medium and high resistance (RMSE range = 0.97–4.57 N). The HRD provides favourable force-generating properties for resisted sprint training and testing, warranting further studies on its exploration in vivo.
... These distinctions may be a product of the temporal and mechanical differences in the ballistic and nonballistic nature of the jump and the 1 repetition maximum, respectively. Specifically, ballistic movements allow for greater propulsive forces and velocity because of the increased acceleration at the end of the movement compared with nonballistic movements (9). Despite these mechanistic differences in ballistic and nonballistic movements, it is recommended that additional research investigate the relationships between ballistic movements (i.e., CMJs) under heavier loads (e.g., 80-120% BM) and 1repetition maximum tests for the purpose of measuring heavy dynamic strength. ...
Geneau, MC, Carey, DL, Gastin, PB, Robertson, S, and James, LP. Classification of force-time metrics into lower-body strength domains. J Strength Cond Res XX(X): 000–000, 2024—The purpose of this study was to classify force-time metrics into distinct lower-body strength domains using a systematic data reduction analysis. A cross-sectional design was used, whereby competitive field sport athletes ( F = 39, M = 96) completed a series of drop jumps, squat jumps, countermovement jumps (CMJs), loaded CMJs, and 2 isometric tasks on portable force platforms, resulting in a total of 285 force-time performance metrics. The metrics were split into 4 test “families” and each was entered into a sparse principal component analysis (sPCA) model. A single metric from each component of each family-specific sPCA were selected based on the loading, reliability, and simplicity of the metric and entered into a second sPCA that included metrics across all tests. The final sPCA revealed 7 principal components each containing 2 metrics and explained a total of 53% variance of the dataset. The final principal components were interpreted as 7 lower-body strength domains: (a) dynamic force, (b) dynamic timing, (c) early isometric, (d) maximal isometric, (e) countermovement velocity, (f) reactive output, and (g) reactive timing. The findings demonstrate that a total of 7 metrics from a drop jump, CMJ, and isometric test can be used to represent ∼50% of variance in lower-body strength performance of field sport athletes. These results can help guide and simplify the lower-body strength diagnosis process in field sport athletes.
... High performance levels can be achieved by combining muscle strength and task specificity [31,32]. Strength is important in tasks that require moving the body while maintaining velocity [35]. For individuals with athletic experience, the simple task of SLJ, which requires explosive horizontal jumping power, may directly involve muscle strength and may be a disadvantage for muscle mass. ...
Muscle strength and mass strongly influence performance. The role of the trunk, upper limbs, and lower limbs in a specific performance is important but unclear in terms of muscle strength, muscle mass, and the degree of influence of each part. Standing long jump is a performance that produces results by not only the muscles of the lower limbs working together but also the entire body, including the trunk and upper limbs. To determine the influence of muscle strength and the mass of each body part on standing long jump, 31 healthy young adults (18 males and 13 females) participated in this study. Abdominal trunk muscle strength, grip strength, and knee extension muscle strength were measured, each of which was defined as trunk, upper limb, and lower limb muscle strength. The trunk, upper limb, and lower limb muscle masses were measured using a body composition analyzer. Performance was measured using the standing long jump test (jumping power). Factors influencing standing long jump were examined. A multiple regression analysis revealed that trunk (β = 0.367, p = 0.006) and upper limb (β = 0.608, p < 0.001) muscle strength values were extracted for standing long jump (adjusted R2 = 0.574, p < 0.01). Trunk and upper limb muscle strength influence standing long jumps.
... Resistance training includes any physical activity performed against an opposing force 2 (resistance). Despite the several types of resistances investigated [1], the commercial 3 availability of free-weights, weight-stack and plate-loaded [2] machines allowed the large 4 application of gravitational and isotonic-like resistances in sport [3] and fitness [4], with 5 a huge potential also for rehabilitation purposes [5]. In general, free-weights are thought to provide constant (gravitational) resistance to the movement, while weight stack 7 machines, thanks to the presence of specifically designed asymmetric pulleys, are 8 deemed to generate isotonic resistance profiles. ...
This study investigated the effect of the inertial component of the resistance ( INERTIA ) at different intensity levels ( LOAD ) on force ( FORCE ), velocity ( VELOCITY ), power ( POWER ), and the muscle activity of the pectoralis major ( EMG PM ), anterior deltoid ( EMG DA ) and triceps brachii ( EMG TB ) muscles during a chest press exercise.
A motor-driven exercise apparatus was programmed to offer resistance with different inertial profiles over the range of movement ( ROM ): gravitational-type constant inertia ( I FULL ); no-inertia ( I ZERO ); linearly descending inertia along the ROM ( I VAR ). Nine healthy adults performed five, maximal-effort, explosive movements with each inertial profile at 30, 50 and 70% of their 1 repetition maximum. Meanwhile, the EMG PM , EMG DA and EMG TB signals were obtained jointly with the FORCE, VELOCITY and POWER readings returned by the exercise apparatus.
One-dimensional statistical non-parametric maps based on 2-way repeated measures ANOVA ( SnPM ) were employed to evaluate the effect of LOAD and INERTIA on the collected timeseries. Paired t-tests were then used as post-hoc tests on the portions of the ROM denoting significant differences in the SnPM .
Higher LOAD resulted in elevated outcomes over large portions of the ROM in all the investigated timeseries. Compared to I FULL , I ZERO allowed greater VELOCITY at the cost of lower FORCE throughout the ROM , while I VAR , despite the lower VELOCITY than I ZERO , resulted in higher FORCE and POWER output. In addition, I ZERO and I VAR elevated EMG TB at the end of the ROM with respect to I FULL . I VAR overcame both I FULL and I ZERO in terms of FORCE and POWER , which indicates that variable inertial profiles might be effectively integrated into resistance exercise programs. Ultimately, this study suggested that INERTIA acts independently to the imposed LOAD on the FORCE, VELOCITY and POWER production. Coaches and therapists are encouraged to account for the type of INERTIA as one of the parameters considered during the exercise selection for their athletes or patients.
... Beyond this region, there is a mismatch between the capacity of the muscle to develop force/torque and the force/torque created by the equipment/external load in favor of the muscle 2, 3 . Variable resistance training (VRT) can be defined as resistance training where the resistance/load varies throughout the joint range of motion to match the external load and the changing muscle force potential 2,4 . VRT has become a popular training modality to ensure that the force capacity of the muscle is sufficiently stimulated throughout the whole joint range of motion 5,6 . ...
Objectives
The aim of the study was to systematically screen the literature and aggregate different effects between variable resistance training (VRT) and traditional resistance training (TRT) on maximal muscle strength and muscle power and identify potential sex- and training program-related moderator variables.
Method
A systematic literature search was conducted in SPORTDiscus, PubMed, and Web of Science. Interventions were included if they compared VRT and TRT in healthy adults and examined the effects on measures of maximal muscle strength and/or muscle power of the lower and/or upper body. A random-effects model was used to calculate weighted and averaged standardized mean differences (SMD). Additionally, univariate sub-group analyses were independently computed for sex and training-related moderator variables.
Results
Seventeen studies comprising a total of 491 participants (341 men and 150 women, age 18–37 years) were included in the analyses. In terms of maximal muscle strength, there were no statistically significant differences between VRT and TRT for the lower (p = 0.46, SMD = -0.10) or the upper body (p = 0.14, SMD = -0.17). Additionally, there were no significant training-related differences in muscle power for the lower (p = 0.16, SMD = 0.21) or upper body (p = 0.81, SMD = 0.05). Sub-group analyses showed a significant moderator effect for training period and repetitions per set for maximal muscle strength in the lower body (p = 0.03–0.04) with larger strength gains following TRT when performing more repetitions per set (p = 0.02, SMD = 0.43). No other significant sub-group effects were found (p = 0.18–0.82).
Conclusions
Our results suggest that VRT and TRT are equally effective in improving maximal muscle strength and muscle power in healthy adults.
... Many studies point out that the development of large impulses, and thus the consequent acceleration of CM, depends on the power capacities of the neuromuscular system (Samozino, et al., 2012). Power is a physical quantity that denotes the amount of work done in a unit of time, i.e., it is a product of inversely proportional quantities of force (F) and velocity (v) (Frost, Cronin, & Newton, 2010). Accordingly, it is possible to generate identical maximum power (Pmax) of the vertical jump, but with different combinations of force and velocity values, i.e., with different mechanical F-v profile of the lower extremities. ...
A detailed review of literature revealed that there is no study of the influence of different types of loads on the performance of a bilateral vertical jump examined on subjects of the same type of F-v profile. Therefore, the aim of this study was to evaluate the influence of two different load-types on the squat-jump performance in force-deficient subjects. During the seven-week training program, the 15 participants of force group performed a half back squat with a load of 80-85% 1RM, while the 15 participants of velocity group performed squat jumps with an unloading of 25% of body weight during the same period of time. The force group significantly improved height of the squat jump (+12.43 ± 6.98%; p <0.001), with a large effect (ES = 1.92 ± 0.72), while in the velocity group were recorded non-significant change (+2.02 ± 5.92%; p = 0.26), with a small effect (ES = 0.30 ± 0.60). These results in the force group were accompanied by a significant optimization of the F-v profile (+31.53 ± 34.91%; p = 0.003), with the attribute of large effect (ES = 1.10 ± 0.65), and the velocity group again recorded non-significant change (-2.20 ± 34.34%; p = 0.70), with a trivial effect (ES = -0.13 ± 0.60). The results of the force group support the hypothesis of the effectiveness of a training program aimed at developing a deficient component of the F-v profile.
... Variable resistance has been introduced as an alternative to constant resistance and a strategy to overcome the sticking region. Variable resistance can be defined as a modality where the resistance/load varies throughout the range of motion [6,7]. It has been reported that, when conducting resistance training at maximal intended velocities, variable resistance leads to faster acceleration and a shorter deceleration phase of the barbell [8]. ...
The aim of the study was to investigate the acute effects of attaching chains on barbell kinematics and muscle activation in the bench press. Twelve resistance-trained men (height: 1.79 ± 0.05 m, weight: 84.3 ± 13.5 kg, one repetition maximum (1-RM) bench press of 105 ± 17.1 kg) lifted three repetitions of bench press in three conditions: (1) conventional bench press at 85% of 1-RM and bench press with chains that were (2) top-matched and (3) bottom-matched with the resistance from the conventional resistance lift. Barbell kinematics and the muscle activity of eight muscles were measured at different heights during lowering and lifting in the three conditions of the bench press. The main findings were that barbell kinematics were altered using the chains, especially the 85% bottom-matched condition that resulted in lower peak velocities and longer lifting times compared with the conventional 85% condition (p ≤ 0.043). However, muscle activity was mainly only affected during the lowering phase. Based upon the findings, it was concluded that using chains during the bench press alters barbell kinematics, especially when the resistance is matched in the bottom position. Furthermore, muscle activation was only altered during the lowering phase when adding chains to the barbell.
... Therefore, the lower force and thus also velocity and power values of FAST-NB compared to FAST-B contractions appear to be a direct consequence of the need to decelerate and avoid projecting the load. The current findings, therefore, support the hypothesis that FAST-B contractions produce superior mean power, force and velocity due to the greater time spent accelerating the load throughout the whole range of motion (Frost et al., 2010). ...
Purpose
Neuromuscular power is critical for healthy ageing. Conventional older adult resistance training (RT) guidelines typically recommend lifting slowly (2-s; CONV), whereas fast/explosive contractions performed either non-ballistically (FAST-NB) or ballistically (FAST-B, attempting to throw the load) may involve greater acute power production, and could ultimately provide a greater chronic power adaptation stimulus. To compare the neuromechanics (power, force, velocity, and muscle activation) of different types of concentric isoinertial RT contractions in older adults.
Methods
Twelve active older adult males completed three sessions, each randomly assigned to one type of concentric contraction (CONV or FAST-NB or FAST-B). Each session involved lifting a range of loads (20–80%1RM) using an instrumented isoinertial leg press dynamometer that measured power, force, and velocity. Muscle activation was assessed with surface electromyography (sEMG).
Results
Peak and mean power were markedly different, according to the concentric contraction explosive intent FAST-B > FAST-NB > CONV, with FAST-B producing substantially more power (+ 49 to 1172%, P ≤ 0.023), force (+ 10 to 136%, P < 0.05) and velocity (+ 55 to 483%, P ≤ 0.025) than CONV and FAST-NB contractions. Knee and hip extensor sEMG were typically higher during FAST-B than CON (all P < 0.02) and FAST-NB (≤ 50%1RM, P ≤ 0.001).
Conclusions
FAST-B contractions produced markedly greater power, force, velocity and muscle activation across a range of loads than both CONV or FAST-NB and could provide a more potent RT stimulus for the chronic development of older adult power.
... Acceleration is therefore a = F /m, i.e., force relative to mass. These laws of mechanics properly explain, for example, how, in the 20-m shuttle run test, a participant with larger fat mass has higher requirements for force production when accelerating their running speed during the test (Frost et al. 2010). Therefore, the test is more strenuous for those individuals with excess adiposity, resulting in a lower performance level. ...
This study entity evaluated how body composition, physical activity (PA) and
maturity are associated with physical fitness (PF) status and development during
adolescence. We furthermore examined PF development on an individual level
and in adolescents with impaired PF. Additionally, we estimated longitudinal
associations between PF and self-rated health (SRH). This study entity was
designed to provide novel information related to the Finnish national Move! −
monitoring system for physical functional capacity and to help interpret the
results at the practical level.
Data from a 2-year longitudinal observational study were used (2013–2015,
n = 970, 12.6 ± 1.3 years, 52.4% girls). Participants completed annual assessments
of PF (Move! measurements: cardiorespiratory fitness (20-m shuttle run),
muscular fitness (push-up, curl-up), fundamental movement skills (throwing�catching combination test, 5-leaps jump), and flexibility (squat, lower back
extension, shoulder stretch)), body composition (bioimpedance), maturity status
(Tanner scale), PA (accelerometer, self-reported) and SRH.
The main findings reveal that PF develops naturally during adolescence,
but that both PF status and development are systematically with practical
relevance attenuated by excess adiposity. Low PF tends to be sustained during
adolescence in a group and at an individual level. PF is cross-sectionally
associated with SRH but does not explain SRH at the 2-year follow-up.
In conclusion, PF measured with weight-bearing assessments reflects an
individual's ability to perform physically demanding tasks. PF attainment can be
supported by healthy weight gain during growth and maturation. PF does not
explain future SRH in this study sample, but PA does, and most coherent
favourable associations are observed with self-rated PA. It is therefore important
to evaluate which variables are the best predictors for health outcomes in specific
populations.
... Moreover, simple ballistic exercises could be considered as safe choices since the external load is projected onto the flight phase (e.g., ball throws), allowing to omit repetitive cycles of hard braking required during high-velocity non-ballistic and plyometric exercises. The advantage is that ballistic exercise was found to generate greater speed and power than the non-ballistic alternative [55,56]. The rationale for these increments is the need to accelerate during the concentric phase of movement to project the object onto the flight phase. ...
With age, many physiological changes occur in the human body, leading to a decline in biological functions, and those related to the locomotor system are some of the most visible. Hence, there is a particular need to provide simple and safe exercises for the comprehensive development of physical fitness among elderly adults. The latest recommendations for the elderly suggest that the main goal of training should be to increase muscle power. The post-activation performance enhancement effect underpinning complex training might be an approach that will allow for the development of both muscle strength and velocity of movement, which will result in an increase in muscle power and improve the ability to perform daily activities and decrease injury risk. This article briefly introduces a complex training model adapted to the elderly with its potential benefits and proposes a direction for further studies.
... According to the latest position of the American College of Sports Medicine on the progression of RT for older adults, an RT program performed with machines and free weights is recommended for older adult beginners . Recently, pneumatic machines have also been used as a device for RT, whereby the body mass represents the only inertia that must be overcome to perform the movement, supposedly reducing the risk of injury (Frost, Cronin, & Newton, 2010;Peltonen, Häkkinen, & Avela, 2013). The RT dose-response relationship to improve muscle strength and physical functioning in healthy older adults has recently been developed (Borde et al., 2015b;Kneffel et al., 2021). ...
The aim of the present study is to compare the effects of 12 weeks of resistance training with machines and elastic tubes on functional capacity and muscular strength in older women aged 60 years or over. The participants were randomized into two groups: a machine group ( n = 23) and an elastic group ( n = 20). They performed 12 weeks of progressive resistance training, twice a week, with similar exercises. Outcomes were assessed at three time points: baseline, postintervention, and 8 weeks after the end of the training. A significant intragroup effect was demonstrated for both groups at postintervention on functional tests and muscle strength. For the functional reach test and elbow flexion strength (180°/s), only the machine group demonstrated significant intragroup differences. No differences were observed between groups for any outcome. At the 8-week follow-up, functional capacity outcome values were maintained. The muscle strength outcome values decreased to baseline scores, without differences between groups.
... These biomechanical differences probably explain why the leg press has the largest bias of all the tested methods (Table 6). Another explanation is the pneumatic resistance in the present leg press apparatus, allowing higher average velocities for a given force due to the absence of inertia [55]. Additionally, the software excludes 5% of the range of motion from the start and end of the movement, inevitably affecting the average values in the lighter resistance conditions to a greater degree compared to the higher resistance conditions, resulting in higher V 0 . ...
The aim of the study was to examine the test-retest reliability and agreement across methods for assessing individual force-velocity (FV) profiles of the lower limbs in athletes. Using a multicenter approach, 27 male athletes completed all measurements for the main analysis, with up to 82 male and female athletes on some measurements. The athletes were tested twice before and twice after a 2- to 6-month period of regular training and sport participation. The double testing sessions were separated by ~1 week. Individual FV-profiles were acquired from incremental loading protocols in squat jump (SJ), countermovement jump (CMJ) and leg press. A force plate, linear encoder and a flight time calculation method were used for measuring force and velocity during SJ and CMJ. A linear regression was fitted to the average force and velocity values for each individual test to extrapolate the FV-variables: theoretical maximal force (F0), velocity (V0), power (Pmax), and the slope of the FV-profile (SFV). Despite strong linearity (R²>0.95) for individual FV-profiles, the SFV was unreliable for all measurement methods assessed during vertical jumping (coefficient of variation (CV): 14–30%, interclass correlation coefficient (ICC): 0.36–0.79). Only the leg press exercise, of the four FV-variables, showed acceptable reliability (CV:3.7–8.3%, ICC:0.82–0.98). The agreement across methods for F0 and Pmax ranged from (Pearson r): 0.56–0.95, standard error of estimate (SEE%): 5.8–18.8, and for V0 and SFV r: -0.39–0.78, SEE%: 12.2–37.2. With a typical error of 1.5 cm (5–10% CV) in jump height, SFV and V0 cannot be accurately obtained, regardless of the measurement method, using a loading range corresponding to 40–70% of F0. Efforts should be made to either reduce the variation in jumping performance or to assess loads closer to the FV-intercepts. Coaches and researchers should be aware of the poor reliability of the FV-variables obtained from vertical jumping, and of the differences across measurement methods.
... Ballistic exercises, where the external load is projected into a flight phase (e.g., throws), are the most commonly prescribed for the development of power output (Suchomel et al., 2018). They have been shown to produce greater velocity and power output than non-ballistic resistance exercises (Frost et al., 2010;Requena et al., 2011). The rationale for these increments is the requirement to accelerate throughout the entire concentric movement in order to project the load into the flight phase. ...
Background: Mechanical power output is recognized as a critical characteristic of an athlete with regard to superior performance during a competition. It seems fully justified that ballistic exercises, in which the external load is projected into a flight phase, as in the bench press throw (BPT), are the most commonly prescribed exercises for the development of power output. In addition, the muscular phenomenon known as post-activation performance enhancement (PAPE), which is an acute improvement in strength and power performance as a result of recent voluntary contractile history, has become the focus of many strength and conditioning training programs. Although the PAPE phenomenon is widely used in the upper-body training regimens, there are still several issues regarding training variables that facilitate the greatest increase in power output and need to be resolved.
Objective: The purposes of this meta-analysis were to determine the effect of performing a conditioning activity (CA) on subsequent BPT performances and the influence of different types of CA, intra-complex rest intervals, and intensities during the CA on the upper-body PAPE effect in resistance-trained men.
Methods: A search of electronic databases (MEDLINE, PubMed, and SPORTDiscus) was conducted to identify all studies that investigated the PAPE in the BPT up to August 2020. Eleven articles, which met the inclusion criteria, were consequently included for quality assessment and data extraction. All studies included 174 resistance-trained men [age: 25.2 ± 2.1 years; weight: 88.4 ± 7.5 kg; height: 1.82 ± 0.03 m; bench press (BP) relative strength: 1.31 ± 0.14 kg ± kg⁻¹] as participants. Meta-analyses of standardized mean effect size (ES) between pre-CA mean and post-CA mean from individual studies were conducted using the random-effects model.
Results: The effect of PAPE in the BPT was small (ES = 0.33; p < 0.01). The BP exercise as a CA at an intensity of 60–84% one-repetition maximum (1RM) (ES = 0.43) induced slightly greater PAPE effect than a ballistic–plyometric (ES = 0.29) and a BP exercise at ≥85% 1RM and at >100% 1RM as well as a concentric-only BP (ES = 0.23 and 0.22; ES = 0.11, respectively). A single set (ES = 0.37) of the CA resulted in a slightly greater effect than a multiple set (ES = 0.29). Moderate rest intervals induced a slightly greater PAPE effect for intensity below 85% 1RM (5–7 min, ES = 0.48) than shorter (0.15–4 min, ES = 0.4) and longer (≥8 min, ES = 0.36) intra-complex rest intervals. Considering an intensity above 85% 1RM during the CA, a moderate rest interval resulted in a similar PAPE effect (5–7 min, ES = 0.3) compared with longer (8 min, ES = 0.29) intra-complex rest interval, whereas shorter rest intervals resulted in a negative effect on BPT performance (0.15–4 min, ES = −0.13).
Conclusion: The presented meta-analysis shows that performing a CA induces a small PAPE effect for the BPT performance in resistance-trained men. Individuals seeking to improve their BPT performance should consider preceding them with a single set of the BP exercise at moderate intensity (60–84% 1RM), performed 5–7 min before the explosive activity.
... 61.3Parameters to consider when classifying, selecting, or designing the exercises Furthermore, we have to contemplate the type of resistance to maximize the objectives of the exercise. Resistance can be classified into the following three different categories[14]: ...
The main goal of a strength program, and especially at high-performance level, is to provide the optimal conditions to allow the players to achieve, maintain, or enhance the proper performance of functional movements significant for basketball.
... The optimization of the bench press exercise studied in this document is intended at understanding the appropriate performance of the bench press exercise in conditions of training to gain endurance or to perform the exercise in the safest manner, that is avoiding overloads. This method can be used to study the muscular response to different resistance systems [28] and define the most appropriate exercise realization in each case. Specifically, in the case of under-studied resistance devices such as the constant-force resistance [29] ; or even for the development of future user-defined variableforce resistance devices based on nonlinear springs [30,31] . ...
The bench press exercise on a Smith machine, frequently used in training programs, can be analyzed as a redundantly actuated biomechanical system. In this exercise, a simplified model having one degree of freedom, actuated at the shoulder and the elbow, provides a meaningful representation of its dynamics. Due to the actuation redundancy, many different combinations of actuations that lead to the same motion can be found. The present optimization framework for the bench press exercise is intended at understanding the appropriate performance of this exercise when it is used to gain endurance or to perform the exercise in the safest manner, that is, avoiding overloads. The dynamic simulation is solved by parameter optimization and direct collocation. The kinematics of the bench press exercise performed by a trained subject and recorded with an electro-goniometer is used as a reference motion for the optimization. The results show that it is possible to mathematically obtain better realizations of the exercise, what suggests the potential of this methodology in the design of training programs in sports or rehabilitation exercises.
The chapter aims to discuss the pivotal role of biomechanics in optimizing athletic capabilities. It seeks to explore how an understanding of human movement mechanics can be leveraged to enhance sports performance across various disciplines. Through biomechanical analysis and application, this proposal intends to uncover insights into technique refinement, injury prevention, and performance optimization strategies. By delving into the intricacies of biomechanics, this chapter aims to provide coaches, athletes, and sports scientists with valuable insights to unlock the full potential of human performance in sports.
Optimizing training to minimize injuries among Ghanaian athletes is the primary focus of this research. This study, conducted at Kumasi Academy, highlights the introduction of revised training protocols that led to a substantial 15% reduction in injury rates, particularly targeting minor injuries such as hamstring strains and knee pains. The research addresses critical aspects such as muscle adaptation, joint health, and the implementation of preventive measures tailored specifically for athletes in Ghana. By focusing on dynamic warm-ups, periodization of training, and advanced biomechanics, the study aims to address common injury issues and enhance overall athlete performance. The revised protocols incorporated strength training, injury prevention strategies, and improved recovery practices, which were shown to be effective in reducing the incidence of minor injuries. The findings of this study not only reflect the benefits of a structured and scientifically informed training regimen and offer valuable insights into how these methods can be adapted and applied across various team sports and athletic disciplines. The results underscore the importance of evidence-based approaches in improving athletic health and extending the career longevity of athletes in Ghana, contributing significantly to sports science and injury prevention. This research provides a model for other institutions seeking to implement effective injury reduction strategies and enhance the well-being of their athletes.
Purpose
Various training factors in combination with high intensity methodologies and techniques have been extensively investigated, with the intention of increasing anabolic, endocrine responses and subsequent structural adaptations. Variable resistance training allows the demands of an exercise to be matched to the muscle’s ability to exert force. The aim of this article is to examine whether variable resistance training produces significant gains in muscle mass compared to conventional resistance training.
Methods
A literature search was performed via PubMed, Web of Science, Cochrane and Scopus with search terms including “variable resistance”, “accommodating resistance”, “flywheel resistance”, “bands resistance”, “eccentric overloading resistance”, “isokinetic resistance”, “elastic resistance”, “variable cam”, “chain loaded resistance training”, “hypertrophy”, “resistance training”, strength training” and “power training” in July 2023. Inclusion criteria were studies that measured direct data related to muscle hypertrophy, compared variable resistance training and conventional resistance training and measured body composition using tape measures, ultrasound, dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging and bioimpedance metres.
Results
Our search identified a total of 528 articles, and 12 studies met the inclusion criteria. The results of the studies analysed show that similar improvements occur, with no significant differences between the two training protocols.
Conclusion
This systematic review revealed that variable resistance training does not produce a greater gain in muscle mass compared to conventional training over a short–medium period of time and with untrained subjects. Therefore, it is necessary to compare these two training methods over longer training periods and with subjects with more experience in resistance training.
Purpose:
To determine the utility of countermovement-jump and Keiser leg-press tests for tracking changes in elite athletes of different sports.
Methods:
Elite athletes of the Norwegian Olympic Federation (126 individuals from 18 sports) performed countermovement-jump and Keiser tests on 2 to 11 occasions between 2014 and 2021. Separate analyses were performed for male and female alpine skiing, male and female handball, male ice hockey, and males and females of other sports. Means and standard deviations of consecutive change scores were combined with short-term error of measurement (3.7%-7.0%) and smallest important changes (2.0%-3.6%, defined by standardization) to determine the proportions of athletes who experienced decisive changes in 2 senses: first, the athlete did not get substantially worse or better (>90% chance of either), and second, the athlete did get substantially worse or better (>90% chance of either).
Results:
Averaged over sports, Keiser peak power and relative peak power had the highest proportions of decisive changes in the first (60% and 55%) and second senses (25% and 28%). The velocity intercept of the force-velocity relationship had the lowest proportions in the first and second senses (29% and 11%), while jump height, Keiser mean power, relative mean power, the force intercept, and the slope of the force-velocity relationship had similar proportions (40%-53% and 15%-21%).
Conclusions:
With the possible exception of the Keiser test velocity intercept, the proportions of observed decisive changes in elite athletes using Keiser measures and countermovement-jump height between tests appear adequate for the measures to be useful for routine monitoring.
Background: the focus of this research is to evaluate the effectiveness of Resistance and Aqua resistance training packages and its impact on selected functional variables among men Basketball players. Method: The purpose of the study is to investigate the Resistance and Aqua resistance training on cardio respiratory endurance and vital capacity among men basketball players. Randomly selected subject was (N=45). This subject has classified into three equal groups of fifteen each (n=15). Age limit of this subjects was between 15 to 17 years. Group-I named as Resistance training, Group-II named as Aqua resistance training, and Group III named as control group. Timeline: The resistance and aqua resistance training had given 50 minutes per day for 3 days alternatively in a week. Likely this training had continued for twelve weeks in Hyderabad, Telangana, India. Functional variables completed of the both groups at zero time. Results: The results on functional variables of cardio respiratory endurance and vital capacity of men basketball players produced significant changes. Conclusion: The advantage of aqua resistance training group had shown significant improvement compared by all the other groups of selected functional variables. Therefore effect of aqua resistance training and resistance training covered in this study is beneficial for the men basketball players.
Background: the main aim of this research is to evaluate the effectiveness of Resistance and Aqua resistance training packages and its impact on selected kinanthropometric variables among Basketball players. Method: Therefore the purpose of the study is to investigate the Resistance and Aqua resistance training on arm span and hand span among men basketball players. The selected subjects (N=45) would be classified into three equal groups of fifteen each (n=15) at random, Age ranged between 15 to 17 years. Group-I undergo Resistance training, Group-II Aqua resistance training, and Group III act as control group. Timeline: The resistance and aqua resistance training consisted of 50 min/day, 3 days in a week till twelve weeks from the Hyderabad, Telangana, India. kinanthropometric variables completed of the both groups at zero time and after twelve weeks of aqua resistance and resistance training intervention group. Results: The results on kinanthropometric variables of arm span and hand length of men basketball players produced significant changes. Conclusion: The advantage of aqua resistance training group had shown significant improvement compared in all the other groups the selected kinanthropometric variables. Therefore effect of aqua resistance training and resistance training covered in this study is beneficial for the men basketball players.
Background: the main aim of this research is to evaluate the effectiveness of Resistance and Aquaresistance training packages and its impact on selected corporeal variables among men Basketballplayers.Method: Therefore the purpose of the study is to investigate the Resistance and Aqua resistancetraining on explosive power and strength endurance among men basketball players. The selectedsubjects (N=45) would be classified into three equal groups of fifteen each (n=15) at random, Ageranged between 15 to 17 years. Group-I undergo Resistance training, Group-II Aqua resistancetraining, and Group III act as control group.Timeline: The resistance and aqua resistance training consisted of 50 min/day, 3 days in a week tilltwelve weeks from the Hyderabad, Telangana, India. Corporeal variables completed of the bothgroups at zero time and after twelve weeks of aqua resistance and resistance training interventiongroup.Results: The results on corporeal variables of explosive power and strength endurance of menbasketball players produced significant changes.Conclusion: The advantage of aqua resistance training group had shown significant improvementcompared in all the other groups the selected corporeal variables. Therefore effect of aqua resistancetraining and resistance training covered in this study is beneficial for the men basketball players.
Keywords: Aqua resistance training, Resistance Training, corporeal variables, Men Basketballplayers.
This chapter introduces the importance to study movement in the sports context, where human performance focuses on the continuous optimization of the physical condition of athletes in specific situations, which often require to be performed at high intensities. To optimize these actions, it is necessary to prioritize strength training, focused on improving useful strength, understood as the application of strength under specific time and velocity conditions per training to competitive exercise (issues reflected in force–velocity and force–time curves). To carry out from practice, it is necessary to monitor, quantify, adapt and prescribe strength training to understand the existing relationship between the external load proposed for the subject and its organic consequences to achieve the adaptations sought and thus optimize performance. To achieve this, it is important to measure and control movement from a mechanical perspective. In this sense, in this chapter, an initial analysis of different methods of strength training through kinetics and kinematics will be proposed.
This narrative review evaluates strength or resistance training on cardiorespiratory endurance, blood pressure, contractile function, contractile protein synthesis rate, bone turnover, gait and balance, and neuromuscular adaptations in elderly populations. Seventy-eight studies spanning from 1999 through 2020 were reviewed. Database sources including PubMed, Science Direct, Web of Knowledge and Google Scholar were searched in accordance with the purpose of the study. A majority of the studies reported that resistance training reduces blood pressure and increases contractile functions, contractile protein synthesis rate, bone turnover, gait and balance, cardiorespiratory endurance, and neuromuscular adaptations in the elderly. Furthermore, combined training (CT), also known as concurrent training (strength plus endurance training) may also be as effective as traditional endurance training or traditional strength/resistance training alone for improving cardiorespiratory endurance and functional performance. According to the evaluation of studies included in this review, we concluded that training modalities that involve low-load, high velocity strength training combined with endurance training might be the best training strategy in improving cardiovascular fitness, functional capacity and musculoskeletal health in the elderly populations. Elderly people should be encouraged to participate in a concurrent training or a combination of strength and endurance training to delay, or even reverse the negative effects of aging.
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The purpose of the study was to nd out the effect of resistance training on selected corporeal variables among Basketball players. For the present study 30 Basketball players from Alagappa University College of Physical Education, Alagappa University, Karaikudi, Tamil Nadu, India were selected at random and their age ranged from 18 to 22 years. The subjects were divided into two equal groups of fteen each. Group-I acted as experimental group (Resistance training group) and Group-II acted as control group. The requirement of the experiment procedure testing as well as training schedule was explained to the subjects so as to get full co-operation of the effort required on their part and before the administration of the study. The study was formulated as a post test only random group design. The duration of the experimental training was eight weeks. After the experimental treatment, all the subjects were tested on corporeal variables namely leg explosive power, cardio vascular endurance and muscular strength. This nal test scores formed as post test scores of the subjects. The post test scores were subjected to statistical analysis using “t” ratio test. In all case 0.05 level of condence was xed to test hypotheses. The resistance training has been established as an effective means to improve explosive power, cardio vascular endurance and muscular strength among Basketball players after undergoing resistance training for eight weeks.
This work aimed to study the influence of velocity on lower limbs force production capabilities during single
and repeated high-intensity exercises (i.e. strength-endurance).
The first part of this work (Partie 1) focused on the type of modeling to draw the force-velocity
relationship during acyclic ballistic lower limb extensions. This first part has brought original results that
support the linearity of the force-velocity relationship, especially on the velocity end of the relationship.
Considering all the force and velocity conditions explored, the linearity was confirmed experimentally over
80% of the total spectrum of the force-velocity relationship (i.e. from 6 to 86% of the theoretical maximal
velocity), even in comparison to a curvilinear modeling.
The second part (Partie 2a) aimed to i) investigate the effect of the force-velocity condition on strength-
endurance (i.e. the maximum number of repetitions), controlling the effect of movement frequency and ii) to
revisit the effect of exercise intensity, commonly expressed relatively to the maximum power obtained at
optimal velocity (Pmax). The results obtained showed that strength-endurance was more affected by exercise
intensity when power output was expressed relative to the maximum power specific to the velocity condition
(Pmaxv) than when it was expressed relatively to Pmax. The results also showed that strength- endurance between
different force-velocity-power conditions was explained at 88% by Pmaxv and at 10% by the force-velocity
condition, in which this relative power is developed. Strength-endurance was greater when Pmaxv was lower and
in high force-low velocity conditions. In addition to the maximum number of repetitions, the high force-low
velocity conditions allowed a greater total mechanical work for a given Pmaxv.
The third part (Partie 2b) aimed at studying the inter-individual variability of the effect of the force-
velocity condition on strength-endurance. Following this study, it was pointed out that the effect of the force-
velocity condition on strength-endurance was not the same for all individuals and in particular that exist different
athlete profiles: some individuals are better in high force-low velocity conditions or in low force-high velocity
conditions. This individual force-velocity-endurance profile gives an indication of the orientation of endurance
capabilities toward high force-low velocity conditions, or vice versa. From a practical point of view, these results
showed that an individual with the best endurance performance in a force-velocity condition and for a given
Pmaxv was not always the best in all force-velocity conditions. In addition to depend on the intensity of exercise,
strength-endurance also depends on this force-velocity-endurance profile.
To conclude, this thesis work has confirmed that the effect of velocity on the lower limbs force production
capabilities during single ballistic movements was linear over all the functional conditions of velocity, in
particular at very high velocities. This work has also shown that in the context of repeated high intensity
exercises, the force-velocity condition in which the power is developed influences strength-endurance
independently of power output and the movement frequency. In addition, the influence of force-velocity
condition on strength-endurance is not similar for all individuals: each individual is characterized by its own
force-velocity-endurance profile. An accurate determination of the force-velocity-power conditions seems
interesting for the evaluation and training of force production capabilities with an individualized approach.
The use of bands in strength training may provide more resistance in sport-specific training, but they may also hinder range of motion and muscle growth.
This experiment investigated the effects of varying bench inclination and hand spacing on the EMG activity of five muscles acting at the shoulder joint. Six male weight trainers performed presses under four conditions of trunk inclination and two of hand spacing at 80% of their predetermined max. Preamplified surface EMG electrodes were placed over the five muscles in question. The EMG signals during the 2-sec lift indicated some significant effects of trunk inclination and hand spacing. The sternocostal head of the pectoralis major was more active during the press from a horizontal bench than from a decline bench. Also, the clavicular head of the pectoralis major was no more active during the incline bench press than during the horizontal one, but it was less active during the decline bench press. The clavicular head of the pectoralis major was more active with a narrow hand spacing. Anterior deltoid activity tended to increase as trunk inclination increased. The long head of the triceps brachii was more active during the decline and flat bench presses than the other two conditions, and was also more active with a narrow hand spacing. Latissimus dorsi exhibited low activity in all conditions.
(C) 1995 National Strength and Conditioning Association
Many authors have recommended the use of surgical tubing, light resistance or isokinetic devices to enhance action and velocity-specific strength gains. The purpose of the present study was to compare the effectiveness of these three types of exercises. Subjects were placed on a 10-week resistance training program, training three times per week using a shoulder press action at approximately 50 percent of their one repetition maximum (1 RM). The training speed was restricted with the use of a metronome to an average angular speed of 3.14 rad[middle dot]s-1. Subjects were randomly assigned to three training groups; Hydragym shoulder press (H), Universal shoulder press (U) or surgical tubing shoulder press (ST). Strength was measured pre- and posttraining on a Cybex isokinetic device (shoulder abduction) and a Universal shoulder press station. Isokinetic torque increased 13.2 percent (p < 0.01) overall (results collapsed over training groups and training speeds). There were no significant differences among groups. Universal shoulder press 1 RM increased 14.8 percent (p < 0.01). Specifically, the Universal training group increased 17.5 percent (p < 0.05), the Hydragym group 14 percent (p < 0.05) and surgical tubing group 13.8 percent (p < 0.05). Training mode differences were not significant. There was no velocity-specific response to training. Thus for the training methods compared there was no evidance of movement-specific or velocity-specific training responses. It can be concluded that all three training methods are equally effective in promoting strength gains.
(C) 1991 National Strength and Conditioning Association
Strength gains have been attributed to neural adaptations such as alterations in recruitment, rate coding, synchronization of motor units, reflex potentiation, co-contraction of antagonists, and synergistic muscle activity. Although most training studies show increases in EMG, a few have shown increase in strength with no apparent changes in neural drive. This may highlight the importance of motor control and the reorganization of supraspinal inputs. High intensity concentric and eccentric contractions with arousal and imagery techniques merit further study in promoting optimal neural adaptations. Specificity of training mode, type of contraction, and angle and velocity have been documented. Most velocity specificity studies have emphasized movement rather than contraction speed, which may be the predominant factor. The high rate of force development achieved with ballistic contractions should serve as a template for power training. The extent of muscle hypertrophy is dependent upon protein degradation and synthesis, which may be enhanced through high intensity, high volume eccentric and concentric contractions.
(C) 1995 National Strength and Conditioning Association
Muscle power diminishes with increasing age and inactivity. The capacity for older adults to increase muscle power with resistance exercise has not been examined; therefore, we examined the influence of progressive resistance training (PRT) on muscle power output in 17 men and women aged 56-66 years, and compared their responses to 15 men and women aged 21-30 years.
All subjects performed 12 weeks of PRT at a workload equivalent to 80% of the one repetition maximum (1RM). All training and assessments of 1RM and power were made on Keiser pneumatic resistance machines. Subjects performed five exercises, three sets per exercise, twice weekly. Muscle power was measured (isotonically) at resistances equivalent to 40, 60, and 80% of the 1RM, on the knee extension and arm pull machines.
All subjects increased arm pull power similarly at 40 and 60% of 1RM, independent of age or sex. There was not a significant increase in arm pull power at 80% of 1RM. Older and younger subjects also had similar absolute increases in leg extensor power at 40 and 60% of 1RM, but men responded with greater absolute gains than women at these percentages (p < .05). The increase in leg extensor power at 80% of 1RM was similar in all groups. Older and younger subjects increased strength similarly in all exercises except the left knee extension. Independent of age, men increased strength more than women in all exercises except the double leg press.
These data demonstrate that individuals in their sixth decade can still improve muscle power (and strength); however, men may realize greater absolute gains than women.
The aim of this study was to investigate the kinematics, kinetics, and neural activation of the traditional bench press movement performed explosively and the explosive bench throw in which the barbell was projected from the hands. Seventeen male subjects completed three trials with a bar weight of 45% of the subject's previously determined lRM. Performance was significantly higher during the throw movement compared to the press for average velocity, peak velocity, average force, average power, and peak power. Average muscle activity during the concentric phase for pectoralis major, anterior deltoid, triceps brachii, and biceps brachii was higher for the throw condition. It was concluded that performing traditional press movements rapidly with light loads does not create ideal loading conditions for the neuromuscular system with regard to explosive strength production, especially in the final stages of the movement, because ballistic weight loading conditions where the resistance was accelerated throughout the movement resulted in a greater velocity of movement, force output, and EMG activity.
The aim of this study was to investigate the kinematics, kinetics, and neural activation of the traditional bench press movement performed explosively and the explosive bench throw in which the barbell was projected from the hands. Seventeen male subjects completed three trials with a bar weight of 45% of the subject's previously determined 1RM. Performance was significantly higher during the throw movement compared to tile press for average velocity, peak velocity, average force, average power, and peak power. Average muscle activity during the concentric phase for pectoralis major, anterior deltoid, triceps brachii, and biceps brachii was higher for the throw condition. It was concluded that performing traditional press movements rapidly with light lends does not create ideal loading conditions for the neuromuscular system with regard to explosive strength production, especially in the final stages of the movement, because ballistic weight loading conditions where the resistance was accelerated throughout the movement resulted in a greater velocity of movement, force output, and EMG activity.
This study investigated the effects of short duration, high intensity training on skeletal muscle. The extensors and flexors of the knee were tested and exercised by means of an isokinetic dynamometer. Measurements of peak torque were obtained at velocities ranging from 0 degrees/sec (isometric) to 300 degrees/sec through a distance of 90 degrees. Total work output was measured during repeated knee extensions and flexions for work tasks of 6 sec and 30 sec duration. A 1-min test of repeated maximal contractions was administered to examine muscular fatiguability before and after training. The subjects trained one leg with repeated 6 sec exercise bouts, while the other leg was trained using repeated 30 sec bouts. All training and testing was executed at near maximal force and at a constant velocity (180 degrees/sec). The subjects trained four times per week for a period of seven weeks. The daily work output was equal for the 6 and 30 sec training legs. Results indicate that: (1) isokinetic training programs of 6 and 30 seconds duration can significantly (P less than .05) increase peak muscular torque; (2) training velocity may be an important consideration in improving peak torque; (3) total work output was increased an average of 30% with either training at relatively slow (60 degrees/sec) or fast (180 degrees/sec) velocities; (4) both training programs significantly reduced the fatiguability of the knee extensor muscles.
Sixteen experienced male powerlifters served as subjects in a training study designed to examine the effect of flexibility training on: (i) the stiffness of the series elastic components (SEC) of the upper body musculature and (ii) rebound and purely concentric bench press performance. Nine of the subjects participated in two sessions of flexibility training twice per week for 8 wk. Prior to and after the training period the subjects' static flexibility, SEC stiffness, rebound bench press (RBP), and purely concentric bench press (PCBP) performance were recorded. The flexibility training induced a significant reduction in the maximal stiffness of the SEC. Furthermore, the experimental subjects produced significantly more work during the initial concentric portion of the RBP lift, enabling a significantly greater load to be lifted in the post-training testing occasion. The benefits to performance achieved by the experimental group consequent to flexibility training were greater during the RBP lift as compared with the PCBP lift. The control subjects exhibited no change in any variable over the training period. These results implied that the RBP performance enhancement observed consequent to flexibility training was directly caused by a reduction in SEC stiffness, increasing the utilization of elastic strain energy during the RBP lift.
Twelve experienced male weight lifters of varying ability completed a series of bench press lifts at 95% of maximum. These lifts included a rebound bench press, which was performed without a delay between the downward and upward components of the lift, a bench press performed without a downward phase, and two bench press movements performed with various pause periods imposed between the downward and upward phases of the lift. Force and cinematographic data were collected during each lift. The augmentation to performance derived from prior stretch was observed to decay as a function of the pause duration. This relationship was accurately described (P less than 0.01) by a negative exponential equation with a half-life of 0.85 s. The nature of this decay is discussed with reference to the implications for stretch-shorten cycle movements that are performed with a period of pause between the eccentric and concentric phases and for stretch-shorten cycle research paradigms.
Twelve experienced male weight lifters performed a rebound bench press and a purely concentric bench press lift. Data were obtained pertaining to 1) the benefits to concentric motion derived from a prior stretch and 2) the movement frequency adopted during performance of the stretch-shorten cycle (SSC) portion of the rebound bench press lift. The subjects also performed a series of quasi-static muscular actions in a position specific to the bench press movement. A brief perturbation was applied to the bar while these isometric efforts were maintained, and the resulting damped oscillations provided data pertaining to each subject's series elastic component (SEC) stiffness and natural frequency of oscillation. A significant correlation (r = -0.718, P less than 0.01) between maximal SEC stiffness and augmentation to concentric motion derived from prior stretch was observed. Subjects were also observed to perform the SSC portion of the rebound bench press movement to coincide with the natural frequency of oscillation of their SEC. These results are interpreted as demonstrating that the optimal stiffness in a rebound bench press lift was a resonant-compliant SEC.
The performance of ten elite powerlifters were analyzed in a simulated competition environment using three-dimensional cinematography and surface electromyography while bench pressing approximately 80% of maximum, a maximal load, and an unsuccessful supramaximal attempt. The resultant moment arm (from the sagittal and transverse planes) of the weight about the shoulder axis decreased throughout the upward movement of the bar. The resultant moment arm of the weight about the elbow axis decreased throughout the initial portion of the ascent of the bar, recording a minimum value during the sticking region, and subsequently increased throughout the remainder of the ascent of the bar. The electromyograms produced by the prime mover muscles (sternal portion of pectoralis major, anterior deltoid, long head of triceps brachii) achieved maximal activation at the commencement of the ascent phase of the lift and maintained this level essentially unchanged throughout the upward movement of the bar. The sticking region, therefore, did not appear to be caused by an increase in the moment arm of the weight about the shoulder or elbow joints or by a minimization of muscular activity during this region. A possible mechanism which envisages the sticking region as a force-reduced transition phase between a strain energy-assisted acceleration phase and a mechanically advantageous maximum strength region is postulated.
The purpose of this study was to investigate the force-velocity response of the neuromuscular system to a variety of concentric only, stretch-shorten cycle, and ballistic bench press movements. Twenty-seven men of an athletic background (21.9 +/- 3.1 years, 89.0 +/- 12.5 kg, 86.3 +/- 13.6 kg 1 repetition maximum [1RM]) performed 4 types of bench presses, concentric only, concentric throw, rebound, and rebound throw, across loads of 30-80% 1RM. Average force output was unaffected by the technique used across all loads. Greater force output was recorded using higher loading intensities. The use of rebound was found to produce greater average velocities (12.3% higher mean across loads) and peak forces (14.1% higher mean across loads). Throw or ballistic training generated greater velocities across all loads (4.4% higher average velocity and 6.7% higher peak velocity), and acceleration-deceleration profiles provided greater movement pattern specificity. However, the movement velocities (0.69-1.68 m.s(-1)) associated with the loads used in this study did not approach actual movement velocities associated with functional performance. Suggestions were made as to how these findings may be applied to improve strength, power, and functional performance.
Athletic strength and power refer to the forces or torques generated during sporting activity. Their assessment can be used for strength diagnosis or talent identification, to monitor the effects of training interventions and to estimate the relative significance of strength and power to particular athletic pursuits. However, strength and power assessment is a difficult task. Reasons for this include: the fledgling status of research within the area, our limited understanding of the mechanisms underpinning strength and power performance and development, and limitations associated with various forms of dynamometry. This article describes a frame work for the collection of data which may ultimately lead to recommendations for the assessment of strength and power in sporting contexts. Such a framework will be evolutionary and depends upon synergistic improvements in our understanding of: the physiological mechanisms underpinning strength and power development; the effect that various training regimens have upon the development of strength and power; and factors influencing the validity and reliability of dynamometry.
Currently, isometric, isoinertial and isokinetic dynamometry are employed in assessment. Each form has its supporters and detractors. Basically, proponents and critics of isokinetic and isometric dynamometry emphasise their apparently high external and apparently low internal validity respectively. While the converse applies for isoinertial dynamometry. It appears that all 3 modalities can have acceptable reliability, however this should be established rather than assumed, as the reliability of each can be threatened by a number of considerations (e.g. instruction for isometric tasks, the impact of weight used during weighted jumping tasks, and the effects of gravity and feedback on isokinetic performance). While reliability is a seminal issue in assessment, it is not the only critical issue. Specifically, there has been little research into the correlation between strength and power measures and athletic performance. This work is central to the use of such indices in talent identification. To date, this work has generally been limited to heterogeneous rather than homogeneous groups. More work is required in this area. Furthermore, not all modes of assessment are sensitive or similarly sensitive to various training interventions. This suggests that these modalities are measuring different neuromuscular qualities. How these qualities relate to performance requires more work, and will determine the contexts in which various strength and power assessment modalities and protocols are used. Following are conclusions from the review: (i) it is unlikely that one assessment procedure can be used for a multitude of ends (e.g. talent identification and monitoring the effects of training); (ii) different levels of athlete ability within a given sport may require different assessment regimens; (iii) minor changes in procedure may alter the usefulness of a procedure and (iv) we must be prepared to question assumptions pervading the field which are based upon anecdotal evidence. There are limitations with, and should be delimitations in the use of the various protocols and forms of dynamometry.
The purposes of this investigation were to assess whether maximal isoinertial (triceps pushdown [TP] and triceps extension [TE]), isometric and isokinetic (1.04, 2.08, 3.14, 4.16, and 5.20 rad·s-1) forearm extension strength measures: 1) presented statistical generality when they were correlated prior to and following 4, 8, and 12 wk of resistance training; 2) were similarly affected by training; and 3) presented statistical generality when their changes as a consequence of training were intercorrelated. Fifteen men (11 experimental and 4 controls) without a history of resistance training participated in the study. Training involved four sets of 8-12 repetitions, each followed by 90-s recovery, at 70-75% one repetition maximum (1RM), three times a week, for 12 wk. Training incorporated the TP, close-grip bench press, and triceps kickback exercises. Prior to and after 4, 8, and 12 wk of training, the intercorrelations among the TP, isometric, and isokinetic indices almost always achieved statistical generality (i.e., r2 > 0.5). It was concluded that the strength measures generally discriminated similarly between subjects. However, the sensitivity of the strength measures to the effects of training were dissimilar. While all strength indices increased with the training, the timing(isoinertial prior to isometric and isokinetic adaptations) and magnitude(TP>TE> isometric>isokinetic) of these adaptations varied greatly. None of the intercorrelations between changes in the strength indices achieved statistical generality. Furthermore, factor (F)-analyses on these changes indicated that in the initial and later stages of training, there were three and four discrete factors, respectively, accounting for strength development. These factors were thought to reflect differential effects of training on the structural, neural (including learning), and mechanical mechanisms underpinning each strength index. Possible applications of this research design in better understanding strength development were also canvassed.
summary: The use of bands in strength training may provide more resistance in sport-specific training, but they may also hinder range of motion and muscle growth.
The purpose of this study was to compare dynamic pushup (DPU) and plyometric push-up (PPU) training programs on 2 criterion measures: (a) the distance achieved on a sitting, 2-handed medicine ball put, and (b) the maximum weight for 1 repetition of a sitting, 2-handed chest press. Thirty-five healthy women completed 18 training sessions over a 6-week period, with training time and repetitions matched for the DPU (n = 17) and PPU (n = 18) groups. Dynamic push-ups were completed from the knees, using a 2-second-up-2-second-down cadence. Plyometric push-ups were also completed from the knees, with the subjects allowing themselves to fall forward onto their hands and then propelling themselves upward and back to the starting position, with 1 push-up completed every 4 seconds. The PPU group experienced significantly greater improvements than the DPU group on the medicine ball put (p = 0.03). There was no significant difference between groups for the chest press, although the PPU group experienced greater increases.
(C) 2000 National Strength and Conditioning Association
Ten untrained 18- to 22-year-old subjects trained one leg using isoinertial fixed-mass (FM) and the other leg using hydraulic resistance (HR) to determine the effect on the torque-position knee flexion curve. Three sets of 10 reps were performed three times a week for 8 weeks. Strength was evaluated using a 1-RM test at 60 and 240[degrees]/sec isokinetically. Both legs increased in 1-RM and isokinetic strength. The FM leg increased more than the HR leg in the 1-RM test and across the range of motion for both isokinetic test velocities. Increases in strength were similar at the different joint positions in the range of motion for both legs. The results indicate that FM training can increase strength at the strongest as well as the weakest points in the range of motion, and that at least for this training protocol and this population of subjects, FM training may induce greater increases in strength than HR training.
(C) 1995 National Strength and Conditioning Association
“Balanced, total body conditioning;” “functional strength, power, muscle endurance and flexibility;” and “cardiovascular/cardiorespiratory efficiency” are the watchwords of Universal’s training philosophy. Muscle strength alone is not enough for optimal athletic performance. What is crucial for the athlete is the ability to use that strength in competitive situations and to “go the distance” successfully. High standards of health and physical fitness, as well as strength, are integral to Universal’s conditioning programs.
The bench press is the current topic for the NSCA Journal feature "Bridging the Gap." Drs. Tom McLaughlin and Nels Madsen discuss the factors influencing performance and injury risk in the bench press. In the companion article, Dave Williams presents the practical applications of training football linemen in the bench press.
(C) 1984 National Strength and Conditioning Association
Traditionally, near maximal isometric efforts have been used to elicit the beneficial facilitations and inhibitions associated with strength and flexibility improvements using proprio-ceptive neuromuscular facilitation (PNF) and modified PNF techniques. Although concentric reversal of antagonists has been used clinically, there is little evidence regarding the concentric contraction speed and resistance levels necessary to elicit an augmented neuromuscular response. This study addresses the question of speed and resistance specificity and their subsequent PNF effects on strength and power outputs. This was accomplished through the use of a double-acting concentric dynamometer (DACD). Twelve males, aged 18-25 years, participated in this study. Each subject performed a reversal of an antagonist maneuver simulating a horizontal bench pull and bench press, all using combinations of slow speed of contraction, fast speed of contraction, and isometric contraction. Within the limitations of this study, it appears that a low-resistance, fast speed of antagonistic contraction significantly increases both peak and average force during a fast agonistic effort (p < 0.05). Neither maximal isometric nor slow concentric contraction of the antagonist (against heavy resistance) seemed to augment the succeeding concentric effort of the agonist under either slow or fast conditions.
(C) 1999 National Strength and Conditioning Association
