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Complex Training with Male Rugby Players: Complex training involves the integration of strength training, plyometrics, and sport-specific movements. A single workout may involve intense strength exercises followed by a plyometric exercise to simultaneously train the nervous system and fast twitch muscle fibers. A slow, heavy strength exercise such as a squat, and a lighter fast, repetition of a sprint, plyometric jump or Olympic lift, can be combined. A heavy, slow movement is followed by a fast repetition. Alternating both plyometric and resistance training with other stretch-shortening activities in the same workout has been shown to be an effective technique.

A study by Comyns, et. al. examined the effect of various resistive loads on the biomechanics of performance of a fast stretch–shortening cycle activity to determine if an optimal resistive load exists for complex training. Twelve elite rugby players performed three drop jumps before and after three back squat resistive loads of 65%, 80%, and 93% of a single repetition maximum (1-RM) load. All drop jumps were performed on a specially constructed sledge and force platform apparatus. Flight time, ground contact time, peak ground reaction force, reactive strength index, and leg stiffness were the dependent variables. Repeated-measures analysis of variance found that all resistive loads reduced (P < 0.01) flight time, and that lifting at the 93% load resulted in an improvement (P < 0.05) in ground contact time and leg stiffness. From a training perspective, the results indicate that the heavy lifting will encourage the fast stretch–shortening cycle activity to be performed with a stiffer leg spring action, which in turn may benefit performance. However, it is unknown if these acute changes will produce any long-term adaptations to muscle function. *Coaching Application: Research suggests that complex training has an acute ergogenic effect on upper body power which also includes improved jumping performance. Improved performance may require 3-4 minute rest intervals between the weight training and plyometrics sets and the use of heavy weight training loads. Studies indicate that complex training is equally or more effective than strength training or plyometric training alone in increasing speed strength and maximum speed.

Reference

Comyns, Thomas M., Harrison, Andrew J., Hennessy, Liam, and Randal Jensen. 2007. Identifying the optimal resistive load for complex training in male rugby players. Sports Biomechanics, Vol. 6, Issue 1.

The importance of ground reaction force (GRF) and the speed with which force is applied during the pushing action away from the ground cannot be overemphasized.These two factors are major determinants of sprint performance for athletes in all sports during each phase of a short sprint.

A study by Nagahara and associates (2017) aimed to investigate the step-to-step spatiotemporal variables and ground reaction forces during the acceleration phase for characterizing intra-individual fastest sprinting within a single session. Step-to-step spatiotemporal variables and ground reaction forces produced by 15 male athletes were measured over a 50-m distance during repeated (three to five) 60-m sprints using a long force platform system. Differences in measured variables between the fastest and slowest trials were examined at each step until the 22nd step using a magnitude-based inferences approach. There were possibly–most likely higher running speed and step frequency (2nd to 22nd steps) and shorter support time (all steps) in the fastest trial than in the slowest trial. Moreover, for the fastest trial there were likely–very likely greater mean propulsive force during the initial four steps and possibly–very likely larger mean net anterior–posterior force until the 17th step. The current results demonstrate that better sprinting performance within a single session is probably achieved by 1) a high step frequency (except the initial step) with short support time at all steps, 2) exerting a greater mean propulsive force during initial acceleration, and 3) producing a greater mean net anterior–posterior force during initial and middle acceleration.

Coaching Application: The more force athletes can apply to the ground, and the faster this force is applied (ground contact time), the greater the start and acceleration speed. Training to increase GRF during early and late acceleration focuses on improving absolute strength (maximum) and speed-strength (applying force quickly each step). Improvement in these areas requires unique training approaches and exercises. *NASE members are referred to the following issues of Sports Speed Digest on the NASE website for specific training exercises and programs:

January: 2015, 2016, 2018, March: 2014, May: 2016, July: 2008, September: 2011, 2014, November: 2013.

Reference

Nagahara, Ryu, Mizutani, Akifumi, Matsuo, Hiroaki, Tetsuo Fukunaga. 2017. Step-to-step spatiotemporal variables and ground reaction forces of intra-individual fastest sprinting in a single session. Journal of Sports Sciences. Pages 1-10 | Accepted 29 Sep 2017, Published online: 07 Oct 2017

1/19/18 NASE Blog Post: Although expensive force plate technology has been around for decades in the labs of researchers, it is now beginning to find its way to university and professional sports teams. Researcher Weyand and colleagues, for example, have used a treadmill-mounted force plate to measure ground reaction force (GRF), rate of force production (RFP), and swing time between stance periods of the same foot for years in their innovative studies on sprinting. According to Carl Valle, “providers of force plate systems and services are growing in popularity—Sparta Science, P3, Andy Franklin Miller, and more. Accelerometer-based products like Bar Sensei and Push have made efforts to capture force production in the weight room.

The ability of the human body to generate maximal power is linked to a host of performance outcomes and sporting success. Power-force-velocity relationships characterize limits of the neuromuscular system to produce power, and their measurement has been a common topic in research for the past century. Unfortunately, the narrative of the available literature is complex, with development occurring across a variety of methods and technology. This review focuses on the different equipment and methods used to determine mechanical characteristics of maximal exertion human sprinting. Stationary cycle ergometers have been the most common mode of assessment to date, followed by specialized treadmills used to profile the mechanical outputs of the limbs during sprint running. The most recent methods use complex multiple-force plate lengths in-ground to create a composite profile of over-ground sprint running kinetics across repeated sprints, and macroscopic inverse dynamic approaches to model mechanical variables during over-ground sprinting from simple time-distance measures during a single sprint. This review outlines these approaches chronologically, with particular emphasis on the computational theory developed and how this has shaped subsequent methodological approaches. Furthermore, training applications are presented, with emphasis on the theory underlying the assessment of optimal loading conditions for power production during resisted sprinting. Future implications for research, based on past and present methodological limitations, are also presented. It is our aim that this review will assist in the understanding of the convoluted literature surrounding mechanical sprint profiling, and consequently improve the implementation of such methods in future research and practice.

Coaching Application: Force plate technology is still in its early stages of development and doesn’t do much more than measure the amount of force that an athlete transfers to the ground over time (GRF and ground contact time GCT) when integrated into a high speed treadmill as with the Weyand studies. Ground reaction force and GCT are two major determinants of speed during the start, acceleration, and maximum speed phase of a short sprint and the ability to measure these values each time the foot strikes the ground is invaluable. Pre- and post-testing following various training programs and exercises can identify the most effective means of increasing both vertically and horizontally-directed GRF, and identify force imbalances between the right and left limbs. However, until equipment costs are lowered and the accuracy and sophistication of force plate technology improves, coaches and athletes should continue to use the field tests described in various issues of Sports Speed Digest to provide estimates of absolute and relative ground reaction force.

References: Cross, Matt R., Brughelli, Matt, Samozino, Jean Benoit Morin. 2017. Methods of Power-Force-Velocity Profiling During Sprint Running: A Narrative Review. Sports Medicine, July, Vol. 47, Issue 7, 1255-1269.

Change of Direction (COD) requires high-speed stopping and starting, acceleration, faking, cutting and reaccelerating, and also contains both a physical and perceptual-cognitive component. Physical components include ground reaction force (GRF), proper form and technique, and sport-specific movements. Key cognitive components include visual scanning, reaction time and decision making based on an opponent’s action. Change of direction speed is considered a preplanned action, whereas agility includes both the physical aspects of directional change and the cognitive and decision making realm (reaction to a stimulus) needed to respond to an opponent’s action. The study described below involves only the physical components of COD.

Mechanical variables during change of directions (for example, braking and propulsive forces, impulses, and ground contact times (GCT), have been identified as determinants of faster change of direction speed (CODS) performance. The purpose of this study was to investigate the mechanical determinants of 180° CODS performance with mechanical characteristic comparisons between faster and slower performers; while exploring the role of the penultimate foot contact (PEN) during the change of direction. Forty multidirectional male athletes performed 6 modified 505 (mod505) trials (3 left and right), and ground reaction forces were collected across the PEN and final foot contact (FINAL) during the change of direction. Pearson’s correlation coefficients and coefficients of determination were used to explore the relationship between mechanical variables and mod505 completion time. Independent T-tests and Cohen’s d effect sizes (ES) were conducted between faster (n = 10) and slower (n = 10) mod505 performers to explore differences in mechanical variables. Faster CODS performance was associated (p≤ 0.05) with shorter GCTs (r = 0.701–0.757), greater horizontal propulsive forces (HPF) (r = −0.572 to −0.611), greater horizontal braking forces (HBF) in the PEN (r = −0.337), lower HBF ratios (r = −0.429), and lower FINAL vertical impact forces (VIF) (r = 0.449–0.559). Faster athletes demonstrated significantly (p ≤ 0.05, ES = 1.08–2.54) shorter FINAL GCTs, produced lower VIF, lower HBF ratios, and greater HPF in comparison to slower athletes. These findings suggest that different mechanical properties are required to produce faster CODS performance, with differences in mechanical properties observed between fast and slower performers. Furthermore, applying a greater proportion of braking force during the PEN relative to the FINAL may be advantageous for turning performance.

Coaching Application: Change of direction speed is largely determined by the amount of force (GRF-ground reaction force) one can apply to the ground with the plant foot and the speed (GCT-ground contact time) with which horizontally- and vertically-directed force is applied to to shorten the braking effect of the plant foot and the step prior to the plant (penultimate foot contact). Correct form and technique is also important in the proper execution of various fakes and cuts used in tam sports, and, in applying greater force application with the penultimate foot-ground contact.

Keep in mind that typical COD drills do not transfer well to specific team sports. It requires ingenuity on the part of coaches and players to develop drills that mimic game situations and the movements commonly encountered during competition. This approach is superior and offers the best opportunity for transfer to playing speed in a sport.

Reference

Dos’Santos, Thomas; Thomas, Christopher; Jones, Paul A.; Comfort, Paul. 2017. Mechanical Determinants of Faster Change of Direction Speed Performance in Male Athletes. Journal of Strength & Conditioning Research. March, Vol. 31, Issue 3, 696-705.

Force, Motion, Speed: A grounded perspective on human running performance: Research has resolved the controversy over what prevents an athlete from sprinting faster once “0” accleration is attained. Previous logic supporting horizontally-directed force as the main factor preventing increased velocity at maximum speed does not hold up. Numerous studies have now identified the main factors limiting an athlete’s maximum (MPH) sprinrting speed.

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Nagahara, et. al. (2017) conducted a well designed stucy to clarify the mechanical determinants of sprinting performance during acceleration and maximal speed phases of a single sprint, using ground reaction forces (GRFs). While 18 male athletes performed a 60-m sprint, GRF was measured at every step over a 50-m distance from the start. Variables during the entire acceleration phase were approximated with a fourth-order polynomial. Subsequently, accelerations at 55%, 65%, 75%, 85%, and 95% of maximal speed, and running speed during the maximal speed phase were determined as sprinting performance variables. Ground reaction impulses and mean GRFs during the acceleration and maximal speed phases were selected as independent variables. Stepwise multiple regression analysis selected propulsive and braking impulses as contributors to acceleration at 55%–95% (β > 0.724) and 75%–95% (β > 0.176), respectively, of maximal speed. Moreover, mean vertical force was a contributor to maximal running speed (β = 0.481). The current results demonstrate that exerting a large propulsive force during the entire acceleration phase, suppressing braking force when approaching maximal speed, and producing a large vertical force during the maximal speed phase are essential for achieving greater acceleration and maintaining higher maximal speed, respectively.

*Coaching Application: While ground reaction forces in both directions are important and require separate and unique strength and neuromuscular training programs and exercises, the critical factor preventing an increase in maximum velocity is the inability to exert additional vertically-directed force to the ground to counter braking force and propel the body back up into the area in the shortest period of time.

NASE Members can access the Sports Speed Digest Archives (search the Index of all Sports Speed Digests by topic keyword) for numerous articles describing specific exercises designed to increase both vertically- and horizontally-directed ground reaction force, including the following issues of SSD (page #s listed after) below. *Reminder: You must be logged into your active yearly NASE account to see these issues and to search the comprehensive NASE Sports Speed Digest Index PDF on the issues web page here.

Sled-pulling and acceleration and maximum speed, Sept. 2011, 10
Acceleration:
Factors affecting, May, 2015, 8-9
First three steps and, June 06, 6
and ground impulse, Mar. 2016, 12
in team sports, Mar. 09, pgs. 1-3
resistance for acceleration, Mar. 2013, pgs. 1-2
improving horizontal acceleration, Jan. 2014, 4-6
and the squat, Mar. 2016, 12
and strength and power, May, 2015, 7-8
and stride rate, May 2016, 9 May 2016, 9
and the start, March, 2015 9-10

Reference
Ryu Nagahara, Mirai Mizutani, Akifumi Matsuo, Hiroaki Kanehisa, and Tetsuo Fukunaga. 2017. Association of sprint performance with ground reaction forces during acceleration and maximal speed phases in a single sprint. J Appl Biomech. Sep 27:1-20. doi: 10.1123/jab.2016-0356.

Sprinting speed during all four phases of a short sprint is determined by the ratio of body weight/ground reaction force (maximum forces applied to the ground in relation to body mass). In theory, improvement occurs by altering one or both of these variables: eliminating excess body fat (weight loss) and/or increasing ground reaction force (GRF).

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NOTE: NASE MEMBERS, For specific speed-strength training programs and exercises related to this blog, see the following issues of Sports Speed Digest: January 2016, May 2016, May 2015, Sept. 2014

Unanswered questions do exist concerning just how the faster runners apply greater mass-specific force to the ground. This and other related factors are analyzed in the study described below.

A study by Weyand revealed that sprint running performance can be investigated relatively simply at the whole-body level by examining the timing of the phases of the stride and the forces applied to the ground in relation to a runners body weight. Research using this approach has addressed a number of basic questions regarding the limits and determinants of human running speed. The primary differentiating factor for the top speeds of human runners is how forcefully they can strike the ground in relation to body mass. A general relationship between mass-specific force application and maximum running speeds results from the similar durations of the aerial and swing phases of the stride for different runners. Recent work has elucidated the mechanism by which faster runners are able to apply greater mass-specific ground forces in the very brief foot-ground contact times sprinting requires.

Weyand provides further clarification of how speed is improved: “The variation present in the patterns of ground force application for sprinters and non-sprinters alike can be predicted from body mass and three stride-specific parameters (contact time, aerial time and ankle acceleration) using an anatomically based two-mass model of the human body. These observations indicate that sprinters exploit a motion-based deceleration mechanism to maximize ground force application. To what extent the dynamic mechanism relies on intrinsic limb strength vs. motor control and timing precision remains to be determined.”

*Coaching Application: Two key objectives for speed improvement in team sport athletes is to utilize various forms of speed-strength training to increase ground reaction force (GRF) in both a horizontal and vertical direction, and to control body mass (weight and muscle) by eliminating excess fat and engaging in training programs that maximize strength gains with minimum muscle hypertrophy. Weyand also indicates that faster athletes exploit a motion-to-force mechanism during the impact portion of ground contact to maximize GRF and attain greater limb velocities before ground contact. In addition, the limb is stopped more abruptly upon impact. Ground contact time and aerial time are additional va the iables affecting speed of movement.

Read the entire article by pasting the information below into your browser to gain additional insight on ground force requirements, the speed with which force is applied, and how elite sprinters are able to strike the ground with more force than average sprinters. Dr. Peter Weyand is an outstanding researcher whose work has paved the way to modern day speed improvement training.

Reference

Weyand, Peter (2017) “FORCE, MOTION, SPEED: A GROUNDED PERSPECTIVE ON HUMAN RUNNING PERFORMANCE,” ISBS Proceedings Archive: Vol. 35 : Iss. 1 , Article 289. Available at: https://commons.nmu.edu/isbs/vol35/iss1/289

The speed with which all four phases of a short sprint (start, acceleration, maximum speed, and deceleration) are completed depends upon the amount of force applied during the pushing action away from the ground (ground reaction force – GRF) each foot strike, and the speed with which force is applied (rate of force production – RFP). With correct form and technique, a maximum amount of force can be applied at exactly the right time, in the right direction, and in the shortest possible ground contact time.

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A study by Nagahara, et. al. (2017) examined the association of sprint performance with ground reaction forces during the acceleration and maximum speed phase

Eighteen male athletes performed a 60-m sprint with GRF measured at every step over a 50-m distance from the start. Accelerations at 55%, 65%, 75%, 85%, and 95% of maximal speed, and running speed during the maximal speed phase were determined as sprinting performance variables. Ground reaction impulses and mean GRFs during the acceleration and maximal speed phases were selected as independent variables. Stepwise multiple regression analysis selected propulsive and braking impulses as contributors to acceleration at 55%–95% (β > 0.724) and 75%–95% (β > 0.176), respectively, of maximal speed. Mean vertical force was a contributor to maximal running speed (β = 0.481). The current results demonstrate that exerting a large propulsive force during the entire acceleration phase, suppressing braking force when approaching maximal speed, and producing a large vertical force during the maximal speed phase are essential for achieving greater acceleration and maintaining higher maximal speed.

Coaching Application: This study supports the findings of numerous other researchers on the contribution of both horizontally- and vertically-directed GRF to acceleration and maximum speed. While horizontal force requirements increase in linear fashion during the start and acceleration phase, nearly 100 percent of force requirements at maximum speed are in a vertical direction. The main factor preventing an increase in the maximum (mph) speed of athletes is the inability to exert additional vertically-directed ground reaction force. Strength training programs (weight room, plyometrics, sprint loading) must contain exercises that increase GRF in both a horizontal and vertical direction and mimic the movements of a sprinter during the acceleration and maximum speed phase.

Reference

Ryu Nagahara, Mirai Mizutani, Akifumi Matsuo, Hiroaki Kanehisa, and Tetsuo Fukunaga. 2017. Association of sprint performance with ground reaction forces during acceleration and maximal speed phases in a single sprint. Journal of Applied Biomechanics. https://doi.org/10.1123/jab.2016-0356

While the squat is regarded as the king of lower body exercises, the bench press ‘takes the cake’ for upper body exercises. The bench press is an excellent movement for developing strength, but there are several situations where this exercise may not be feasible. For example, use of the barbell may force the shoulder joint into certain positions throughout the end-range of motion which may be painful or contraindicated for athletes with upper extremity injuries (e.g., rotator cuff, biceps tendonitis, etc.). Alternatively, teams and rehab clinics may not have access to bench press equipment. Therefore, alternative methods for developing upper-body strength that do not require heavy or expensive equipment is desirable.

A new study published ahead of print in the Journal of Strength and Conditioning Research compared a progressive push-up program with a progressive bench press program in moderately resistance trained individuals. Twenty three adult males were divided into a push-up group (n=14) and a bench press group (n=9). Before and after a 4 week training intervention, subjects were tested for 1 RM bench press, push-up progression, medicine ball put and left pectoralis major muscle thickness (via ultra-sound). Both the bench press protocol and push-up protocol were standardized relative to individual bench press or push-up levels. The following push-up variations were used in the training progression; regular push ups, close-grip push ups, uneven push-ups, 1 and 1/2 arm push-ups, archer push-ups and single-arm push-ups.

The results showed that 1 RM bench press strength improved significantly after the training intervention in both groups, with no between-group differences. Push-up progression also significantly improved after training in both groups, however the push-up group experienced significantly greater improvements than the bench press group. No changes in either group were observed for pectoralis major muscle thickness or medicine ball put. The lack of change in muscle thickness indicates that changes in strength were largely due to neural adaptations. Overall, these results indicate that substantial improvements in upper body strength can be made using push-up progressions. This provides a practical and cost-effective alternative for teams who do not have access to weight-room equipment.

Reference:

Kotarsky, CJ., et al. Effect of Progressive Calisthenic Push-Up Training On Muscle Strength and Thickness. Journal of Strength and Conditioning Research. In press.

 

Inadequate recovery can substantially impact athletic performance and increase risk of illness or injury. Therefore, it’s no surprise that organizations invest plenty of time and money in technologies and facilities that are intended to enhance and speed up the recovery process. However, there remains considerable debate surrounding the efficacy of various recovery modalities. For example, research evaluating the effectiveness of various hydrotherapies and compression tools is conflicting. Perhaps greater attention should be given to the single most effective recovery tool available; sleep. There is little doubt that quality sleep facilitates physical and psychological recovery. Despite this awareness, it does not appear that teams are maximizing the regenerative and restorative properties of sleep. The first step in addressing sleep with a team is to determine how athletes are sleeping and how the training schedule may impact it.

A new study published ahead of print of the journal of Science and Medicine in Football quantified sleep quality in a team of Portuguese professional soccer players across various nights. Baseline measures of total sleep duration, sleep-onset latency, sleep efficiency, and wake episode duration were acquired across three days of normal training among twenty five players. These values were subsequently compared to sleep measures obtained from nights following home versus away matches as well as day time versus night time matches. Sleep data was acquired via wrist-based actimetry. The authors wanted to determine if markers of sleep quality differed for each context

The results showed that baseline total sleep duration was 6:36 hours and sleep efficiency was 85% which did not significantly differ from values obtained from day matches. These values are substantially lower than the guidelines for healthy sleep ranges which recommend 7-8 hours of sleep and >90% sleep efficiency. Total sleep duration was approximately 1 hour below baseline and day-match values following night matches. Interestingly, total sleep duration was 77 minutes higher following away matches versus home matches. These results suggest that the full effects of sleep quality are not being maximized at the professional level and that attention to sleep quality and duration should be prioritized.

 

 

Reference:

Carriço, S., Skorski, S., Duffield, R., Mendes, B., Calvete, F., & Meyer, T. (2017). Post-match sleeping behavior based on match scheduling over a season in elite football players. Science and Medicine in Football, 1-7.

Neuromuscular training for youth athletes typically involves calisthenics, plyometric exercises, change of direction drills and speed training. Ample research has demonstrated that pre-pubertal athletes can significantly improve markers of performance with neuromuscular training despite experiencing minimal changes in muscle hypertrophy. However, the timing or sequencing of neuromuscular training may impact training adaptations. For example, when athletes train for neuromuscular development and aerobic fitness conditioning on the same day, there is potential for the interference effect to limit performance gains. This is an important consideration for coaches of youth athletes who typically do not have the luxury of holding separate sessions for specific training qualities on separate days due to time constraints. Therefore, it would be useful for coaches to know the optimal sequencing of training qualities when limited to a single training session ~3 times per week.

A new study published ahead of print in the Journal of Strength and Conditioning Research evaluated the sequencing effects of neuromuscular training and traditional tennis training on performance markers in elite youth tennis players. A total of 16 trained tennis players (~13 years old) were matched and randomly allocated to a group who performed neuromuscular training before tennis practice and a group who performed neuromuscular training after tennis practice. The neuromuscular training protocol was the same for both groups and involved maximal countermovement jumps, box jumps, drop landings, medicine ball throws, hurdle hops, depth-jumps, lateral bounds, acceleration/deceleration and change of direction drills. Workouts were performed 3 times per week for 5 weeks. Workouts were held either 30 mins before or after tennis practice. Before and after the training intervention, all subjects were tested for sprinting speed, 5-0-5 agility, countermovement jump, overhead medicine ball throw and tennis serve velocity.

The results showed that the group who performed neuromuscular training before tennis practice experienced small to moderate improvements in sprinting speed, agility, countermovement jump, overhead medicine ball throw and serve velocity (effect sizes ranged from 0.22 – 1.08). By contrast, the group who performed neuromuscular training following tennis practice experienced trivial or negative changes for all performance markers with agility showing the largest decrement. This study demonstrates that neuromuscular training can effectively improve markers of performance in youth tennis players when performed prior to tennis practice, but not after. Therefore, coaches should refrain from implementing this type of training after team practices.

Reference:

Fernandez-Fernandez, J. et al. Sequencing Effects of Neuromuscular Training on Physical Fitness in Youth Elite Tennis Players. Journal of Strength and Conditioning Research. In press.