Role Of Strength In Power PDF

Role of Strength in Power Greater muscular strength is associated with enhanced force-time characteristics (e.g. rate of force development and external mechanical power), general sport skill performance (e.g. jumping, sprinting, and change of direction), and specific sport skill performance, but is...

Role of Strength in Power Greater muscular strength is associated with enhanced force-time characteristics (e.g. rate of force development and external mechanical power), general sport skill performance (e.g. jumping, sprinting, and change of direction), and specific sport skill performance, but is also associated with enhanced potentiation effects and decreased injury rates. Role of Strength in Power Stronger athletes produce greater F (Peak Force) Stronger athletes produce greater F in a shorter amount of time (Rate of Force Development) Role of Strength in Power Greater muscular strength is associated with enhanced force-time characteristics (e.g. rate of force development and external mechanical power), general sport skill performance (e.g. jumping, sprinting, and change of direction), and specific sport skill performance, but is also associated with enhanced potentiation effects and decreased injury rates. Ballistic Training Target the Force-Velocity Curve Law of Diminishing Returns + 3-5 years + 3-5 years 90 kg Bench Press 150 kg Bench Press 175 kg Bench Press 15kg Shot 15kg Shot 15kg Shot 16% 10% 8% Strength Deficit Strength Association Strength Reserve The importance of strength Strength Trained vs Ballistic Trained Explosively trained athletes produce greater F in a shorter amount of time that strength training alone Improving Strength & Power Training Considerations Resistance training modalities; • Exercise selection • Complex training • Variable RT • Other Improving Strength & Power Resistance Training Modalities Power = Force x Velocity therefore exercise selection should emphasize one or both of these characteristics Improving Strength & Power Resistance Training Modalities Complex Training Methods – completing a traditional RT exercise prior to performing a biomechanically similar ballistic exercise. Improving Strength & Power Resistance Training Modalities • Variable Resistance Training – the external resistance varies throughout the movement depending e.g. top vs bottom position of the squat • Typically the resistance increases as the athlete ascends with the aim of maximizing concentric Force production • The use of bands/chains may enhance the training training adaptation, specifically ROFD compared to constant loading Improving Strength & Power Other Considerations • Bodyweight training – most basic and accessible form of RT, useful in low or untrained individuals but resistance is limited i.e. difficult to OVERLOAD • Unilateral vs Bilateral – interestingly unilateral ex’s has been shown to produce comparable improvements in speed to bi-lateral ex’s, however greater stability = greater capacity to express Force • Plyometrics – considerable body of research supporting the use of plyometrics to enhance power characteristics. Very specific modality for athletes that must largely manipulate their own body weight or light implements. Improving Strength & Power Training Considerations Loading Considerations: • Training to failure • Optimal loads Loading Considerations Training to Failure Discussion Point: • Heavy loads will ultimately lead to increases in muscle strength but should athletes train to failure? • Training to failure with stimulate high threshold motor units BUT may increase the risk of overtraining (high CNS demand) and acute injury (spasm, strain etc.) • Should be used sparingly - testing, team building etc. What Type of Loading Should We Use to Increase Power? Loading Considerations Optimal Loads Guidelines for strength development are long established but loads that maximize power out may be individual, joint and exercise specific A range of loads is necessary to enhance both high and low force power characteristics The amount of time dedicated to each portion of the F-V curve may be identified in a Needs Analysis Improving Strength & Power: Training Status Loading Considerations Training Status • An athlete’s training status will determine what exercises can be tolerated and what their training emphasis should be • Strength development is the cornerstone of Power and should always be prioritized in weaker/untrained individuals • Power orientated activities may also be included but should not be prioritized until a firm strength base has been established • One cannot be powerful if they are not strong, therefore a high level of strength will allow athletes maximize ballistic training Velocity Based Training Velocity Based Training (VBT) is by definition a “form of auto-regulation of training, where day-to-day fluctuations can be accounted for by adjusting the training load” (Mann et al, 2015). What Is Velocity Based Training (VBT)? • Estimate an athlete’s 1RM • Identify proper training loads when fluctuations in muscle performance occur as a result of life stressors • Identify proper velocities and loads to train at to enhance specificity of training and monitor fatigue (VBT Zones) • Receive immediate feedback on performance, ability and motivation of the athlete through velocity of the movement THE FLUCTUATING NATURE OF STRENGTH • One role of the S&C practitioner is to ensure that optimal manipulation of load is prescribed in response to improvements in strength and residual fatigue build-up. • It seems sensible to assume that across the course of a training block, maximal and relative strength levels will fluctuate in response to confounding variables such as sleep, nutrition, competition, technical training etc. • The need for the regulation of load, therefore, becomes essential to optimise the training stimulus and ensure the desired physiological adaptations are elicited at the appropriate times based on longer term periodisation of training. THE FLUCTUATING NATURE OF STRENGTH USING VELOCITY BASED TRAINING TO AUTO-REGULATE Velocity-Based Training (VBT) is another autoregulatory method available to S&C coaches to aid load prescription, assist with traditional prescriptive and periodisation methods and optimise sessional loads in an objective and flexible manner, reacting to the impact of positive and negative training stressors. Through the simple tracking of barbell concentric mean or peak velocity in the key, ‘bang for your buck’ exercises, practitioners have a number of options at their disposal to prescribe load and quantify the impact of fatigue or strength development, ensuring athletes are training at the desired absolute (kgs) and relative (%) loads and reducing any ‘guess work’. USING VELOCITY BASED TRAINING TO AUTO-REGULATE Coaches can then decide the degree to which they want to implement VBT into their prescriptions, depending on factors such as access to equipment, time, number of athletes and desired complexity TRAINING ZONES The utilisation of training zones is a common strategy for load prescription for S&C coaches. These zones are derived from where they typically sit along the forcevelocity curve (driven by research), with associated percentages of 1RM being applied for prescription purposes. Maximal strength, strength-speed, speed-strength, maximal velocity, and power are all common zones used for training blocks. Recently, mean and peak velocities have been mapped to these training zones, providing practitioners with a method of ensuring their athletes are working at the desired intensities. TRAINING ZONES It is important to recognise, however, that whilst this adds an additional layer of objectivity, these zones are quite large, and can potentially reduce the opportunity for specific loading and velocity tracking. TRAINING ZONES • Speed (>1.3m/s): Moving a minimal load as fast as possible, so as to maximise speed. • Speed-Strength (1.3 – 1.0 m/s): Moving a light load as fast as possible. • Power (1.0 – 0.75 m/s): Moving a moderate load as quickly as possible. The priority here is on strength with speed being secondary. • Strength-Speed (0.75 – 0.5 m/s): Moving a relatively heavy load as fast as possible. This will be a slow movement but it’s emphasized to move the weight as fast as possible. • Maximal Strength (<~ 0.5 m/s): This is using a very heavy load, which ends up being a slow movement. (Mann, Kazadi, Pirrung & Jensen, 2016) INTERPRETING VBT DATA There are many ways to interpret the data gained as a result of VBT. Many use VBT in performance testing, as rehabilitation markers and as a load prescription tool, to name a few. Once the data is initially collected for an athlete, the accurate development of a load/ velocity profile can be made, and from that can be used to give a more insightful comparison of individuals, and their monitoring of changes over time. The athletes minimal velocity threshold (MVT) can also be identified, which is the velocity associated with an athletes 1RM. MVT is exercise specific and remains stable even with changes in athletes 1RM over time. Therefore, knowing the MVT for a given individual and exercise allows for 1RM estimation using submaximal loads (Jovanović & Flanagan, 2014). INTERPRETING VBT DATA Velocity profiling can help estimate daily readiness of an athlete, which can in turn be used to alter a training programme to suit how the athlete is performing on the day, which in turn helps to avoid injury. Due to its immediate feedback it can also be helpful for identifying and targeting specific training qualities, such as fatigue and exertion, and has also been shown to motivate athletes to apply consistent maximal lifting effort which in turn has been associated with positive training effects (Randell et al., 2011; Randell et al., 2011). To aid in this process, VBT zones can be identified in order to terminate a set when the mean concentric velocity of a repetition falls below that predefined value. Improving Strength & Power Summary 1. Strong athletes may produce more Force but ballistic training unlocks the potential to increase ROFD 2. Time spent developing developing different components of the ForceVelocity curve will depend on training status and needs of the athlete 3. Training priorities (Force, Velocity or Both) should be periodized and reflected in exercise selection 4. Training to failure is not recommended to enhance strength-power characteristics 5. Strength underpins power