Boxing Science-Punching Power

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Within this article I am going to explain some of the science behind power and strength adaptation from gym based resistance training. I will also concentrate on one of my favourite gym based training methods Compensatory Acceleration Training. I will explain how this method increases strength and power resulting in improvement in your punching power.


Boxing as a sport requires many physical abilities. Speed, strength, power, agility, endurance and coordination make up a total package in a boxing performance. Every individual has different strengths and weaknesses dictated mainly by genetics and training. You can’t legally change your genetics but how you train can greatly affect your power output.


Ask any boxer "would you like to hit harder" and the answer would normally be yes. A boxer’s physical abilities need to interact to produce a physical skill. How hard you can punch relies on serval different physical abilities working in combination.


  • Strength- A boxer’s ability to produce force
  • Speed and the resulting power- How fast a boxer’s nervous system and muscles work to deliver a punch
  • Agility and Coordination-A boxer’s ability to move and transfer force though their body to their fist

Power Equation

Take a look at the above equation to increase power you need to increase the force (Strength) and or decrease the time (Speed) this will result in a larger power output.

The word “Power” in the term Punching Power gives us an important focus for improving this skill. Power is defined as the rate of performing work. It is a measure of how much energy is created in each second that passes, the size of the force applied (Strength behind the punch) and the velocity (Speed of the punch) at which it is applied. It’s not only how strong you are but how fast you can apply that strength to a punch.

 Muscular Strength Adaptation

There are two main areas that are affected by strength adaptation on a muscular level, Intramuscular and Intermuscular coordination.

Intramuscular coordination

One way of increasing punching power is to focus on increasing power and strength within a muscle. Intra muscular coordination is the coordinated recruitment of motor units within a single muscle. The three main factors involved with an increase in muscular coordination are;

  1. Motor Unit Recruitment
  2. Rate Coding
  3. Motor Unit Synchronisation


1. Motor unit recruitment

A Motor unit is made up of a bundle of muscle fibres and a single nerve that will innervate that group. In general there are two types of motor units slow twitch and fast twitch. In reality there are subgroups in each category based on different characteristics of the muscle fibres. Each motor unit is always made up of the same fibre type. Generally speaking slow twitch fibres are for endurance fast twitch are for speed and strength.

Although boxing needs the use of both slow and fast twitch fibres, punching power requires the recruitment of fast twitch fibres to produce maximal force. Fast twitch fibres are considered high threshold units. This means you need a heavy tension for fast twitch unit activation. If the tension for fast twitch is not sufficient enough nothing happens. This is called the all or nothing principle. The greater the number of motor units you activate the more strength and power you will produce.

When beginners start resistance training they usually have trouble recruiting large numbers of fast twitch motor units. One of the early adaptions of strength training is usually the ability to recruit more motor units. This is an important factor for boxing because in most cases you want an increase in power with a limit increase in bodyweight.

With boxing, high threshold fast-twitch motor units are responsible for speed and power output. This is due to the high forces theses motor units are capable of generating. Therefore, when designing a resistance based programme the main focus should be on activating these motor units.

2. Rate Coding

Resistance training over time will increase the firing rate of motor units. This is known as rate coding. At lower levels of intensity 50-80% of 1 repetition max an increase in force is mainly due with an increase in motor unit recruitment. But at high levels of intensity 80-100% of 1 repetition max an increase in force is almost exclusively produce by an increase in firing rate (rate coding).

3. Motor Unit Synchronisation

At lower levels of intensity, motor units fire in asynchronous pattern (some motor units are active others are inactive).This pattern will help prevent fatigue by letting some motor unit recover whiles others work. There is some evidence that synchronisation of motor unit (firing at the same time) can be seen after specific power and strength training. The more motor units firing at the same time the greater the force production the harder you hit.

Intermuscular coordination

Even a simple exercise like bicep curls needs complex coordination between several muscles. Boxing is a complex sport with a multitude of movement patterns which places a huge demand on coordination between different muscle groups throughout the whole body.

Human movement works by transferring force though different body segments to produce movement. When training for improving strength and power a boxer should concentrate on training the entire body. Use similar movement patterns seen in boxing (Punching, Footwork and Defence). Isolation exercises should only be used for rehabilitation work or correcting muscular imbalances.

When a complex strength exercise such as cable wood-chop is used the body has to coordinate between muscles of the legs, torso, upper body and arms. This has a similar movement pattern to throwing a hook. Over time you will improve your ability to coordinate force throughout the entire movement pattern, which in turn will give you an increase in force production (punching power).

Improving strength and speed using gym based resistance training

How much force (Strength) you can generate is governed largely by factors such as:

• Genetics (Body composition, Nervous System, biomechanics) 
• Type of strength training 
• Experience strength training (How long you have been training for)
• Age
• Injuries (Acute and Chronic)

How much speed you can produce in a punch is governed by factors such as:

• Genetics (Body Composition, Nervous System, biomechanics) 
• Type of speed training 
• Experience strength training 
• Boxing Technique 
• Age
• Injuries (Acute and Chronic)

Gym Based Strength and Speed Training

Most boxers want an increase in functional strength with limited gains in mass. This is the exact opposite to body-building. Unfortunately for sports people resistance training in gyms was popularised body-building in the 60's and 70's. This still affects the style of training many people do in gym today including some boxers. Body-building or Hypertrophy Training uses the 12 to 8 rep range while focusing on time under tension slow and controlled. This style is great for increasing muscle mass not so good for functionality and power to weight ratio.

“The nervous system is very specific train fast be fast, train slow be slow”

I believe the most affective type of training a boxer should be doing in the gym is power training. Focusing on strength and speed at the same time. There are 3 main styles of gym based power resistance training you find.

• Light Weight Explosive Training
• Compensatory Acceleration Training
• Combination Training

Light Weight Explosive Training

Light weight explosive training requires a moderate load (Around 30% 1RM) moved as quickly as possible for reps. This style is often used by boxers in the gym who are scared of gaining muscle mass from heavier loads at lower reps. I have a couple of issues with this sort of power training for boxers. Firstly it’s too similar to heavy bad work and body weight plyometrics you get from specific boxing training. You will be doubling up on same sort of training and risk overuse injuries. Secondly, with some exercises at speed you must decelerate the weight at the end of the power curve which will affect power output and will hinder possible adaptation.

Compensatory Acceleration Training

Compensatory Acceleration Training is a style of strength training whereby the lifter attempts to accelerate as much speed as they can while lifting a very high load.(In this case 85-90% of 1Rep max). The eccentric phase is done in slow and controlled manner. In the concentric phase try to lift as fast as you can. Because of the high load the movement in real term will be slow but when it comes to the nervous system it’s the thought that counts. A velocity based strength training combines both speed with heavy weight training recruits powerful high threshold motor unit and the muscle fibres they activate. This function can be explained by the size principle of motor unit recruitment

boxing power

Fig 1.The Size Principle.

The order of motor unit recruitment is controlled by the size principle. You recruit the small muscle fibres first with the lowest threshold (slow twitch) and the largest muscle fibres with the greatest activation threshold (fast twitch) last. Most muscles in the body are a mix of the different motor unit types. The percentages of unit types will change between different muscle groups and between different individuals depending on their genetics. In mixed muscles containing both fast and slow motor units the slow twitch units will always be used regardless of the magnitude of tension or speed of contraction. Activation of full fast twitch motor unit will be very hard to achieve. With the right style of resistance programming you will see an increase in fast twitch motor unit recruitment giving an increase in power output. Recruiting fast twitch motor units should be a priority for boxing specific training.

Combination Training

Combination training is simply a mixture of light explosive training and Compensatory Acceleration Training. You can try different combination between the two styles for example superset one set of each. ( 1 set 5-3 reps @ 85-95% 1 RM followed by 1 set 15 reps @ 30% 1RM )


  • Gym based resistance training is best used with heavy velocity training for boxing specific punching power.
  • Limit the time spent with endurance or body-building style training
  • Unilateral and asymmetrical exercises should be the main focus.
  • Follow an proper periodised programme specifically designed for boxing




Zatsiorsky, V. M., & Kraemer, W. J. (2006). Science and Practice of Strength Training. (Second Edition). Champaign, IL: Human Kinetics.

 Richard Leonard BSc Sports and Exercise Science

Personal Trainer

M: 07511468490

Web: Personal Training Clifton




Twitter: @LesmillsPT