Have you been to a zoo recently? You might see a collection of animals behind bars. They have some space to roam but, for the likes of the speedy cheetahs, not enough to get up to full speed and hunt.
Imagine how the cheetah in the zoo feels: pining against his primal urges, wishing to unleash himself and test his speed against the wildlife of the plains.
Would anyone disagree that the natural, uncaged environment is best for this, and many other animals, as long as mankind stops destroying their habitats?
Why do you imprison your children?
Let children run and move outside
There has been a trend in recent years to ‘professionalise’ high school sports. This often means trying to copy what is seen at the college or professional sports level. Or, what is perceived to be done at those levels.
This has meant that high schools have literally put cages into their gyms: calling them ‘Power cages’ (sic) does nothing to diminish the fact that movement is restricted.
No one calls the cheetah enclosure, a ‘power enclosure’ (not yet, anyway). The limited definition of most ‘S&C’ coaches confuses ‘power’ with ‘force’ and this means increasing ‘power’ by adding load to the young athlete.
Quick physics reminder
P=(fxd)/t
Power = (force x distance)/ time.
Power will increase if you do things further and faster, not just adding more load to increase force.
‘The problem is NOTthat athletes have too great a spatial awareness.’ Sprint Coach Vince Anderson.
Cages restrict movement and limit speed: the two things that young athletes need to develop. The ‘S&C’ ‘coach’ can justify the expense of the cage by showing how much more mass the young people are moving. Despite the fact that it is slow and has limited range. The environment dictates and limits the scope of programming.
These environments have been dominated by American Football (US) and rugby (Commonwealth countries) and ignore sports where moving external mass (another human, heavy objects) is not part of the sport.
Fencing, badminton, tennis, hockey, soccer, netball, basketball and squash, to name a few, require fast, agile, coordinated athletes (The d and t of the power equation).
If you are training young athletes, then think of how they can improve their speed, coordination, agility and range, often at the same time. How does putting them in a cage help?
Free the children, free your mind. Break the shackles of groupthink.
I presented two workshops last month at a conference for gymnastics coaches: speed training and plyometrics myths.
The coaches ranged in age, experience and their gymnastic discipline.
There is no one size fits all approach to gymnastics, so I tried to cover the underlying principles first so that the coaches could then apply it in their own context.
I made sure I asked questions first: what were their concerns, existing practices and type of gymnast they work with.
Coordination for running
We then did practical drills with progressions from simple to complex.
Was my opening question at yesterday’s Continuing Professional Development (CPD) workshop for strength and conditioning coaches.
“Force times velocity” was the text book response from the ex- students.
They are of course technically correct, but how does this affect how we train our athletes? What about momentum, force, impulse, velocity, mass and acceleration?
Powerlifters are powerful (high force, low velocity) as are gymnasts (low force, high velocity). Most sports people fall somewhere in between these extremes, or use different parts within their sport.
Applying power
The workshop was split into three parts:
Terminology and theory: I went through this in some detail and based it on questions I have been asking since I saw Jack Blatherwick present two years ago at GAIN (see below).
Practical exercises to develop acceleration. This included detail look at the snatch and assistant exercises to help develop the snatch. I also covered runs, jumps and throws for the “application” cornerstone.
Programme design: the coaches had prepared a 4 week programme to develop power and they shared and discussed this in small groups.
(One interesting question came up: velocity is a vector quantity, it has a direction. If power was force times speed, then the direction of travel would be irrelevant. So, if we develop power in one direction, why would that apply in another?)
“What are the best ways to train for acceleration of body weight?”
As part of my preparation for the workshop I trying to find research that was both current and measured what we are trying to train (rather than some abstract concept only lab technicians are interested in).
I contacted Jack Blatherwick hoping he might point me in the right direction, instead he was kind enough to respond with his thoughts:
Coaches: Trust your logic. Some research and propaganda is misleading.
I do not want to leave the impression that a coach should avoid research. Read everything you can, but do it knowing there is likely to be something incorrect or misleading along with those things that are helpful.
There’s something good in every article, even the worst pseudoscience … but misleading information is quite prevalent in current popular thoughts about Power and Force.
Acceleration = Speed, Quickness, and Agility
What is ‘Acceleration?’ In kinematics (the most basic topic in Physics, dealing with movement), ‘Acceleration’ is defined as any change in velocity, encompassing all changes in direction and speed.
Agility is included in this definition, because we associate agility in sports with quick changes in direction, like cutting sharply to dodge around an opponent, or perhaps cornering at high speed on the hockey rink.
Speed is also included, because even at relatively constant speed, there is deceleration and acceleration with each stride. Horizontal acceleration of body weight is therefore one of the highest priorities in sports that feature
speed, quickness, and agility.
In other words, for this priority, the critical question is: “What are the bestways to train for acceleration of body weight?”
However, for some reason, throughout history, coaches asked for research on Force and Power, and this has led to training advice that might not be the best fit for acceleration of body weight.
Kinetics
Their question seems entirely logical, and advances the discussion to ‘Kinetics,’ the second basic topic in physics, because we are certainly accelerating a mass.
Therefore, Force and Power would seem to be logical extensions of our question: “What are the best ways to train for acceleration of body weight?”
But … it is an absurd thought (which no one intended) that nerves and muscles might understand the following abstractions:
Force = Mass x Acceleration
Power = Energy Expenditure / Time = Work / Time = Force x Distance / Time = Force x Velocity
Nerves and muscles only understand (and remember!):
(a) how fast they have been trained.
(b) through what range of motion.
(c) how much effort this takes.
That is called SPECIFICITY, the principle that performance is enhanced when the training ‘looks and feels’ like the desired outcome (my simplistic definition, not to be blamed on anyone else).
Therefore, if ACCELERATION is a priority for our sport, and we use the abstraction (F=ma) we are not violating any formulas from physics … but we might be wrong.
Consider the continuum (Force = Mass x Acceleration) that represents various speeds and weights, along which we might choose our training exercises:
The thought is that to improve acceleration we must increase Force, and strength coaches love to do this by increasing the mass we lift in the weight room. But, of course, the more mass we lift, the slower the acceleration. Might this be considered a good way to train for slow acceleration?
Please don’t misunderstand my purpose. I believe in lifting weights – sometimes heavy weights, at an appropriate age and level of fitness. But, it is obvious that we must also incorporate more training in which we accelerate our body mass as quickly as we can.
Complex Training
Furthermore, in every weightlifting exercise, there is a deceleration (to zero velocity) toward the end of the range of motion. This occurs at precisely the moment when sprinting and skating require an explosive acceleration.
Considering that we are ALWAYS forming neuromuscular habits when we train, there should NEVER be a phase of the year in which we excludequick acceleration from the program, and just work on strength.
In fact, I believe every strength exercise should be accompanied in some way with an explosive exercise featuring acceleration: jumps, weighted jumps, sprints, hills, sleds.
Neuromuscular learning occurs with every movement. Myelin is being formed along axons which innervate muscle fibres that are training at high speed.
Timing is a critical part of athletic development, and slow training – if overdone – will certainly not enhance quickness, agility, and speed.
Peak power?
The simplest word (acceleration) for our highest priority has been needlessly replaced by Force and Power.
The word ‘POWER’ has so many colloquial uses that it is often misinterpreted in communications between the physics (biomechanics) lab and the important group of users: athletes and coaches.
One question that has been examined for decades is: “What is the optimum amount of weight to be incorporated into a training exercise to maximize power?” Research is inconclusive, but many believe the optimum weight should be about 30% of a maximum lift with one repetition (1RM).
How important is this question for sports that depend on speed, quickness, and agility?
If the question had been: “What is the optimum weight to lift to maximize ACCELERATION?” The answer is “Zero. Just use bodyweight.”
Many coaches and athletes (as well as scientists and professors) incorrectly believe that explosiveness or explosive starts from a standstill are where athletes demonstrate the greatest power, like exploding out of the starting blocks.
But, looking at the equation Power = Force x Velocity, it is easy to see that there needs to be substantial velocity for Power to be a maximum. Of course there also needs to be a high rate of acceleration as well,because Force = mass x acceleration (F=ma).
Think of it this way: If an athlete accelerates at the same rate between zero and 5 miles per hour as he does between 5-10 mph, his Power is greater from 5-10, because velocity is greater. Usain Bolt’s graph of velocity vs. time (modified from IAAF data), demonstrates this point clearly.
His maximum power does not occur at the start. That is where acceleration is greatest. Power does not peak until a couple of seconds into the sprint where both acceleration and velocity are high.
Explosive movement from a standstill is not where an athlete expresses peak power. When we observe a dragster take off at the start, it is common to use the word ‘powerful.’ But the dragster exerts much greater power somewhere later in the race.
Training Programme Design
ACCELERATION is the correct and simplest word for quickness and agility, and this is the highest priority in many sports, except where the athlete has to move large external masses.
In designing training programs, keep in mind the objective. If the athlete needs to accelerate his own body weight to be successful, there should be a lot of that in training programs.
Heavy strength training is slow acceleration. That does not mean it is wrong, but it must be accompanied by the fast acceleration of body weight (as seen in the video below of midfielder, Sam Malcolm: note the single-leg landing and push-off).
Jack Blatherwick
Thanks very much to Jack for that excellent advice. We kept touching upon training principles yesterday: coaches like doing what they are comfortable with as well as what the physical constraints of their “weights room” dictates.
Reminding ourselves constantly that we are trying to develop better athletes, rather than solely bigger numbers in the gym is crucial!
The greatest challenge for any strength & conditioning/athletic development coach is to elicit specific adaptions on the athlete in order to gain an advantage on the field of play. Specificity can arise in the form of biomechanical, metabolic, or psychological adaptations1. However, recent focus on specificity has taken on a new chapter, with the development of Siff & Verkhoshansky’s2 dynamic correspondence model.
Definition
Dynamic Correspondence: This concept emphasises that all exercises for specific sports be chosen to enhance the required sport motor qualities/movement patterns in terms of several criteria which include:
• the amplitude/direction of the movement • the accentuated region of force production • the dynamics of effort • the rate and time of maximum force production • the regime of muscular work
Furthermore, the theory proposes that the strength displayed in the execution of a given movement be referred to only in the context of that given task.
Sport movement tasks are specific and goal-directed and the enhancement in their execution should also be treated as such. Because of this, exercises should be evaluated based on the type of transfer that they may possess in relation to the degree of skill performance increase.
After this is established, exercises and/or training techniques can further be classified into categories such as general physical preparation (GPP) or special physical preparation (SPP).
Force Velocity Curve
Evaluating the effectiveness of DC can only be decisive with the use of the force velocity curve alongside this argument. The force velocity curve (figure 1) shows an inverse relationship between force and velocity (e.g. the heavier the weight you lift (force), the slower you lift it (velocity); conversely, the lighter a weight, the faster you lift it).
Figure 1: The force velocity curve and its suggested training values
Therefore, different types of training occur on different parts of the force-velocity curve. As you go from high force, low velocity to low force, high velocity, you go from max strength work all the way down to speed strength work on the other side of the spectrum.
Force Velocity and Dynamic Correspondence
So how does this help athletes and does the curve work in unison with DC? It is agreed that a desired effect of training is to produce greater force outputs at a higher velocity compared to pre-training values 3.
Figure 2 shows what happens to the force velocity-curve after strength training (blue line) and speed training (green line).
Figure 2: The force velocity curve and its relationship with strength (blue) and speed (green) training
In advanced athletes, if you train at one end of the force velocity curve, you will improve that part of the curve, but the other will decrease. so can we train all the way along the force-velocity curve?
The problem is your body can only adapt to so much. If you train all strength qualities at the same time, you won’t adapt optimally, hence why periodisation has taken on significant popularity amongst sports coaches.
One principle of periodisation is to move from general training to more specific training 4. Strength is just general preparation whereas power and speed are more specific. So your periodisation plan should travel from left to right down the force-velocity curve .
This concept, however is not new to the strength and conditioning world; Kurz5 highlights how the strength training year needs to be divided up into 3 phases:
General strength.
Functional strength.
Specific strength.
This seems to clash with DC’s suggestion on enhanced specificity.
In conjunction with this, the main bulk of research into the DC theory seems to advocate Olympic lifting, a highly specific and technical exercise, as the main component to enhance sporting capacity.
Olympic Lifting
The snatch
The use of DC alongside Olympic lifts in a programme seems to be the most popular training method when searching the current literature on the topic.
According to Stone et al.,6 the hang power clean/snatch is a dynamic lift that is multi-jointed with a need for co-ordination and fluidity within the movement, which will increase power production and sports performance in an athlete.
The argument being that this lift incorporates the triple extension with the force that is required, ensuring that the correct amplitude and direction of the force is apparent with many sporting movements, such as the engagement of the rugby scrum.
However, on closer inspection of the scrum it seems the primary direction of force is horizontal rather than vertical!
Hori and colleagues7 suggest that the rate of force development from the hang clean/snatch exercises in Olympic lifting also has a realistic transfer for rugby players. This part of the lift (2nd pull) exhibits the most force, ensuring the lower limb contracts at speed to hold a dominant position during the engage of the scrum. This would seem to tick several of the boxes in the DC checklist.
Limitations of the DC theory
From all the information above it could be suggested that the use of Olympic lifts in the athletes programme will be a useful addition to rugby forwards. However, research needs to further its examination into the effect of Olympic lifting on other sports; as the bulk of work seems to come from heavy contact sports such as Rugby Union/League and American Football.
Three notes of caution should be considered before assuming DC and Olympic lifting guarantees specific athletic training.
Firstly, one could misinterpret the conditions of dynamic correspondence to mean that an athlete must literally copy the specific sport task during the training movement.
This occurs quite often when you jump utilising a weighted vest, sprints towing a sled, or swings a bat representing a heavier load than the individual typically swings.
These types of methods have been shown to be effective at times depending on the load being utilised but they also have their limitations. For example, larger loads often greatly alter the biomechanics of the movement which, in turn, will most likely force the athlete to alter finally rehearsed movements.
Second, in an attempt to accelerate the progress of the athletes, many sports performance professionals will implement dynamic correspondence too early in the progression of an athlete’s mastery.
An attempt to have certain athletes, especially young athletes, perform exercises of specific nature before they are fully ready will only inhibit the long-term athlete development of the given individual.
The reason for this is he/she may not have attained sufficient levels of general physical qualities (such as strength or flexibility), optimized sporting skill technique, or perfected appropriate neuromuscular programs prior to performing exercise of a specific nature
Finally, once incorporation of these training exercises are employed, one must address the all-important issue of just how much of the overall training volume is being consumed by DC type exercises versus those of more general nature in a structured training plan.
Though the idea ofperiodisation has been studied extensively, this final point of caution has only been addressed on a limited basis and no clear recommendation can be made yet at this point.
What about going sideways?
Another difficulty with dynamic correspondence is its relationship with change of direction performance (COD or agility). In terms of the training studies, traditional strength and power training methods (i.e. Olympic-style weightlifting and plyometrics) have been shown to enhance functional performance8 9.
These training methods have been utilised in several training studies and are commonly used by strength and conditioning coaches. However, these traditional training methods have failed to improve COD performance.
This failure can be due to the commonality in the design of these studies, which include bilateral movements in the vertical direction. Conversely, COD movements often occur unilaterally in the vertical-horizontal and/or lateral direction, and require anteriorposterior (braking and propulsive) and mediolateral force production10.
Unfortunately, there is a distinct lack of research which investigates the correlations between unilateral horizontal jumping and COD performance. It could be speculated that since CODs require vertical-horizontal force production, horizontal jumping would be highly correlated with COD performance and could enhance COD performance with training.
Furthermore, for those sports requiring lateral force production (squash and tennis), the effect of lateral-type jumps needs to be investigated 11. Dynamic correspondence fails to highlight how a general to specific continuum, involving both bilateral and unilateral strength training can still have a great effect on performance while maintaining the sports specific qualities needed to succeed in the athletic arena.
Jumping, sprinting and changing direction are all general motor skills which need a variety of training methods to consistently overload and progress the athlete.
Conclusion
It should be noted that the principle of specificity will vary greatly according to the training status, physical preparation levels, maturation status, and overall level of sport mastery of the athlete2.
Athletes that are at a lower level of sports mastery may benefit from nearly any training modality and in turn could see positive transfer of training to commonly executed sport tasks; most likely caused by the neural adaptations occurring2.
Transfer will take place much easier in lower level athletes due to their high sensitivity levels to physical activity. Their room for adaptation is much larger than their more advanced counterparts.
As an athlete progresses in sport and training mastery, training methods must take on a greater emphasis of sports specificity in order to result in the desired adaptation1.
This does not just mean Olympic lifting, you can use different overload variations.
Brett Richmond
Suggestions for future research
Effects of DC on different classifications of sport, not just rugby union such as:
Track and field: Discus throwing
Invasion: Soccer
Racquet: Tennis
A need to develop a testing procedure which measures DC effect on off balance sports such as the single leg hop and hold. It can also be used as a functional assessment looking at ankle, knee, hip rotation and technical stability on a grading score line.
Gamble, P. (2006). Implications and applications of training specificity for coaches and athletes. Strength & Conditioning Journal, 28(3), 54-58.
Siff, M., & Verkhoshansky, Y. (Eds.). (2009). Supertraining (6th ed.). Rome: Verkhoshansky.
Zatsiorsky, V., & Kraemer, W. (Eds.). (2006). Science and Practice of Strength Training (2nd ed.). Champaign, IL: Human Kinetics.
Bompa, T, O., & Haff, G, G. (Eds.). (2009). Periodization: Theory and Methodology of Training (5th ed.). Leeds: Human Kinetics.
Kurz, T. (2001). Science of Sports Training: How to Plan and Control Training for Peak Performance. Island Pond, VT: Stadion Publishing Co.
Stone, M. H., O’Bryant, H. S., Mccoy, L., Coglianese, R. & Lehmkuhl, M. (2003). Power and maximum strength relationship during performance of dynamic and static weighted jump. Journal of Strength and Conditioning Research,17, 140-147.
Hori, N., Newton, R., Nosaka, K., & Stone, M. (2005). Weightlifting exercises enhance athletic performance that requires high-load speed strength. Strength and Conditioning Journal, 27, 34-40.
Tricoli, V. A., Lamas, L., Carnevale, R., et al. (2005). Short-term effects on lower-body functional power development: weightlifting vs vertical jump training programs. Journal of Strength & Conditioning Research, 19(2), 433-437.
Kotzamanidis, C., Chatzopoulos, D., & Michailidis, C., et al. (2005). The effect of a combined high-intensity strength and speed training program on the running and jumping ability of soccer players. Journal of Strength & Conditioning Research, 19(2), 369-375.
Brughelli, M., Cronin, J., Levin, G., & Chaouachi, A. (2008). Understanding Change of Direction Ability in Sport. Sports Medicine, 38(12), 1045-1063.
Blazevich, A. J., & Jenkins, D. G. (2002). Effect of the movement speed of resistance training on sprint and strength performance in concurrently training elite junior sprinters. Journal of Sport Science, 20, 981-990.
“The best way to get in shape is not to get out of shape.”
Jim Radcliffe strength coach at Oregon University has been coaching there for 26 years (That is longer than most “S&C coaches” in the UK have been alive). Unlike a lot of people who have been in situ for a long time, he isn’t resting on his laurels in a comfort zone of repeating the same thing year after year.
Instead he has developed an outstanding sequence of practices and structures that allow him to deal with big numbers of big guys in limited time. Here is a review of some of his workshops at GAIN in 2011.
The Warm Up
Teach and train the warm up. Working on “pillars of strength” routines that warm up the body from the core outwards. One of the first exercises taught is the “hip hinge”.
Stand as if ready to jump, fingers on hip bones. Then imagine a table has hit your thighs, pinch your fingers and bend forwards. Keep working this movement forward and backwards.
Then work on a progression from hip hinge to hip extension. The weight training exercises such as good mornings,deadlifts, catches follow this progression.
Sprint progressions he uses are:
Starts (from various positions).
Accelerations from 5-25 yards
Barefoot speed drills.
Sprint intervals (notice that these are last once the mechanics are right).
“Keep healthy, refreshed, sharp”
Radcliffe defined the various aspects of strength as follows:
Core strength : bodyweight vs gravity
Absolute strength: overloads regardless of condition
Relative strength: overloads/ % of bodyweight
Dynamic strength: overloads / degree of speed
Elastic strength: overloads/ degree of rebound.
With Athleticism increasing from top to bottom.
Within these concepts the type of overloadcan be changed to affect the training outcome:
“The more weight you lift, the slower you move.” So time in the weight room can make you train slow to be slower, or train fast to be slower.
It is better to concentrate on “movement efficiency” how you project your hips. You need more force, but then move faster too. Work on “Flex, extend, rotate” to apply this force.
The long term objective is explosive power which comes from:
Functional Strength
Directional Speed
Transitional Agility.
The short term objective is Power (endurance) reliability which comes from:
Work capacity (not necessarily more, but better)
Recoverability
Stamina.
The training cycle
Radcliff uses 14, 21,or 28 day training cycles, and uses a multitude of formats within that. He categorises the lifts as either single joint , double joint or multiple joints. He then uses sets and reps as either fixed, plateau, stimulation or wave.
All of these are adjusted during the training cycle to allow adaptation and stimulation to take place. So even if the lifts stay the same, the ways, means and loads on them differ all the time.
The weekly cycle
Within the week, Radcliffe looks at training different emphases. For example a few days might be on vertical jumps and tosses, another on horizontal jumps with bounds and hops. He uses different complex patterns that utilise strength and power together such as:
Squat\ Jump
Pull\ toss
Push | Pass
Lunge\ Bound.
Radcliffe is dealing with big numbers of players remember (30 is a small group) so the system of training has to reflect this.
Summary
As Oregon have had some great successes recently, no small amount of credit can go to Radcliffe.
What I liked about Radcliffe (and all the presenters), was how he had consolidated his thoughts and practices into easily digestible chunks for the young athletes.
He has a system that is adaptable, rather than off the shelf, and has been proven in practice. Over the 4 years he has the guys, he can see the progression and introduce his key principles. That is what makes him one of the best strength trainers out there.
Dan Baker has been training the Brisbane Broncos for 15 years, and has had many research articles published. The JSCR isn’t that interesting nowadays, the quality of research is poor, but Baker’s articles are always worth reading- innovative, practical and done with really good athletes- not students.
This seminar looked at some of that research, and explained how Baker decided on which aspects ofstrength andpowerto work on and develop. This was good for me to see how he had come to his conclusions, and I got an insight into his decision making process.
There was a lot of information in this lecture, but here are some of the key points that I took away:
Testingand measuring explosive power gives information to the coach that can then be tailored to the athlete, even within a squad environment. A continuum of speed power (0-20% 1RM) ballistic power (20-40%1RM), maximal power (40-60% 1RM), explosive power (60-80%1RM) and max strength (80-100% 1RM) is used.
Organisation is key in training squads. An example of one session is a 6 minute warm up followed by: bench press 10×10 @60%1RM, incline dumbbell row 10×10 (each db 33% 1RM of bench press) then 10×10 crunches. As a complex, and it starts every 3 minutes. So you can get 10 sets done in 30 minutes. Such high rep activity has an immediate negative effect on power output which is more pronounced in stronger athletes.
In contrast training, one form is to use 65%1RM @6 reps (after which power declines) followed by a lighter weight explosive action of 30-40% 1RM. Another is to use agonist\ antagonist complex training which helps increase power output. For example using pulls or cleans followed by jerks or bench throws.
To create a within repetition difference, chains are useful, try 10-20% of the total load, this works well for experienced athletes. Baker uses a chain bench press, followed by bench throws complex with 75 seconds rest between exercises.
Start with body weight
Baker doesn’t chuck people in at the deep end- there is a progression within the Broncos, getting the athletes young and early. From 13-15 years they develop the body structures with various exercises. Then from 15-17 they introduce barbell exercises at 6-15 reps, and then from 17-18 look at heavier strength training. Most of the changes occur in the first 4 years of the heavy strength training, after that the fatigue induced by playing means it is a case of not getting weaker.
Baker trains hypertrophy just short of fatigue (a common theme of this conference) so a couple of reps short of failure for the first 2 sets, followed by a 3rd set hard. He includes some isometric strengthening exercises around sticking points within the sessions.
Someone asked a question at the end – “If you had one thing that came up as a result of your training and experience what would it be?”
Dan Baker replied “hard work”. Funny how it comes back to that a lot of the time.
This lecture was informative and entertaining, I recommend you read Baker’s research, but more importantly have some kind of thought process and structure to your training philosophy. This was probably the only lecture in the whole conference given by a true Coach (that I saw anyway) and more emphasis on Coaching should be given.
I had a quick chat with Dan after the lecture, and he was good enough to talk about some other ideas and experiences including wrestling\ grappling and conditioning drills.
Was my opening question at yesterday’s Continuing Professional Development (CPD) workshop for strength and conditioning coaches.
The workshop was split into three parts:
What is ‘Acceleration?’ In kinematics (the most basic topic in Physics, dealing with movement), ‘Acceleration’ is defined as any change in velocity, encompassing all changes in direction and speed.
Their question seems entirely logical, and advances the discussion to ‘Kinetics,’ the second basic topic in physics, because we are certainly accelerating a mass.
Furthermore, in every 
His maximum power does not occur at the start. That is where acceleration is greatest. Power does not peak until a couple of seconds into the sprint where both acceleration and velocity are high.
ACCELERATION is the correct and simplest word for quickness and agility, and this is the highest priority in many sports, except where the athlete has to move large 
Another difficulty with dynamic correspondence is its relationship with change of direction performance (COD or agility). In terms of the training studies, traditional strength and power training methods (i.e. Olympic-style weightlifting and
Teach and train the warm up. Working on “pillars of strength” routines that warm up the body from the core outwards. One of the first exercises taught is the “hip hinge”.
