top of page
The 10% Rule!
What is it and how can it help you?

Getty Images

As a Soft Tissue Therapist and Coach, I see many clients suffer avoidable injuries.


The objectives of this article are to help increase self-awareness and understanding about

  1. the effects of training on the body

  2. how the 10%rule can help you get more from your training

  3. how the 10% rule can help to reduce the risks of injury 


The 3 most common causes of suffering unnecessary injury are:

  1. returning back to training too soon after illness or injury

  2. ramping up training too quickly, and/or

  3. over-training and insufficient rest to allow the body to adapt to the training loads being placed upon it


In part, this is due to lack of awareness about how training effects the soft tissues (muscles, tendons, ligaments and fascia), how long the body takes to recover from training and how the accumulation of training can lead to overload and injury. Knowledge of these factors can result in more informed training choices and minimise the risks of injury. 

The rule: increases of approximately 10% over current training load is necessary to stimulate

progressive improvements in fitness. The 10% rule is commonly used in the world of fitness training and

nutrition. It offers individuals guidance on the amount of stress / overload is needed to stimulate a

physical response to training. The 10% rule offers a safer way to train avoiding common errors made by

many i.e.:

  1. doing too much too soon

  2. over training; and

  3. increasing the risk of being injured


It is importantly first to understand two important and closely linked factors that influence training:

  1. Training overload

  2. Training progression




To enable improvements in levels of fitness to be made, the body must be exposed to increased physiological stresses or [managed] ‘overload’. Managed overload [as distinct from misjudged overload] triggers a calculated physiological response and adaptations occur improving the

body’s ability to function more efficiently. People who are new to exercise or training will tend to experience a higher rate of improvement, often motivating them to train more, possibly to over train. This is why it is so important to understand the demands of training and its effects on the

body if further beneficial improvements are to continue, injury free.

[Managed] overload is the process of applying a calculated training load that is hard enough to push your body beyond its current adapted level of fitness, but not excessively so, to a level beyond your comfort zone, but within a safe capacity. It involves stressing the physiological

systems beyond the adapted level. Improvements in fitness can only be achieved if greater than previous demands are made on you [the energy system under training].

Progressive training must place an increasing demand on body systems if the desired adaptations [improvements] in fitness levels are to take place; an increase of approximately 10% in training load is required for this to occur. If training loads are increased too quickly, the body will not have time to adapt and this may result in injury and / or fatigue. If training loads are increased too slowly, the training effect will be limited with only minimal improvements. Managed overload can be applied over a single session or a series of sessions.

The rate of improvement is related to the four F.I.T.T. principles (elements) of training; Frequency - Intensity - Time – Type (for more information click on these links or The four F.I.T.T. principles are used to establish guidelines for both endurance and resistance training. They can be applied by people

wishing to improve cardiovascular levels (endurance) and, through resistance training, to develop strength and

other components of fitness i.e. speed, power, endurance, and flexibility). Following these simple guidelines can

ensure that all essential aspects of training are covered within a training plan that is designed to improve levels of


Progression involves a combination of managed overload and rest-regeneration. Once adaptations are made to

training, increases or changes in training load must continue to be made in a managed way in order for

improvements in levels of fitness to continue. Over time, some or all of the ‘F.I.T.T.’ elements may be modified.

The degree to which they are modified depends on a range of variables such as, requirements of the sport, age,

genetics, experience, lifestyle / work balance, strengths, weaknesses, and responses to training.

Frequency and Time (duration) are fairly self-explanatory, simply referring to how often sessions occur and their duration, respectively. For example, a session that is much longer than normal would produce a duration overload effect. In any given period, training more often than is normal would also produce an overload (frequency overload effect). Therefore, care must be taken when applying progressive overloads. As a rule of thumb, increases in training load should ideally be limited to an increase of around 10% in any one of the F.I.T.T. elements over the period of a week for people new to exercise or returning back after a break of more than 4 weeks (where fitness levels would have been significantly reduced).

10% progression is about the minimum amount of overload required for muscles to adapt without causing damage to soft tissue with increased soreness. Building up gradually will allow you to build muscle strength whilst allowing the tendons and ligaments time to adapt to the new loading. Sudden and / or excessive changes in loading will increase the risk of damaging muscle fibres, compromising their ability to function optimally and, over time, the increase the risk of injury through the accumulation of harmful overloading effects.


As fitness levels build through the application of sound training principles, and in combination with a greater understanding of a) the effects that different types of training have on your body, and of b) how external factors such as work / lifestyle may impact your training, then the 10% rule can be flexed a little. Developing self-awareness enables you to understand your body better and its response to training; everyone is different. Understanding what your body does / does not respond well to is key when designing a bespoke training program.


The most important thing to remember is that your body needs time to adjust to training loads / changes in order to improve. Ignoring rest days whilst continuing to expose the body to high volumes / intensities of training without incorporating rest / recovery time within your training plan will a) impede the body’s natural healing processes, decreasing the rate of recovery from training sessions / races, b) augment fatigue levels, thus compromising integrity of the muscle and c) inhibit optimal function during further training, increasing the likelihood of worrisome niggles and the on-set of injury.




Top Tips

  • Listen to your body: this is the most important of all the tips. If your body is experiencing pain / discomfort, then you are already on your way to becoming injured. The feeling of pain is your body telling you that something is not right. Ignoring it will not make it go away. Sometimes, with rest alone, the pain goes away, but for most, as soon as training resumes, the pain returns. Listen to the warning signs; these are the worrisome niggles that we feel intermittently. Seeking advice from a sports / physio therapist is the right thing to do here. They will be able to advise and treat, helping you get back on track!

  • Know your body: knowing what your weak areas are and thereby avoiding the types of activity that place stress on weakened areas. Ask yourself if your body is strong enough to cope with the demands of your sport? Participating / competing in the sport alone will not get you properly fit for that sport; you need to condition your body using sound training methods to meet the demands your sport will place upon your body.

  • Understand gender-specific physiological issues that give a predisposition to injury; be aware and take

       appropriate precautions when you exercise in terms of strength, power, flexibility, etc.

  • Understand effect of fatigue: Training whilst the body is overly fatigued increases the risks of injury and

      reduces the efficiency of your immune system (your body’s innate ability to fight off infection / viruses).

      It is better to shorten the training session or rest than to continue with the session as originally planned; listening to your body and adapting        your training will allow you to continue training rather than having to take time out to recover from illness / injury further down the line.

  • Understand the benefits of rest: It is a misconception that the more you train, the better you will become

      at your sport. Rest is a critical component of good training; it can make you stronger and prevent the

      injuries of overuse, fatigue and poor judgement. Training consecutive days, or twice a day, increases

      the chances of injury, so management of individual sessions, particularly with regard to ‘intensity’, ‘time’

      and ‘type’, and where they are positioned within the week, are equally important. Avoid high-intensity

      sessions back-to-back as they will impede recovery and accelerate fatigue, compromising muscle

      contraction efficiency.

  • Know your sport: Poor technique can lead to injury. Fatigue can promote poor technique. Therefore, training whilst fatigued reinforces poor technique and results in an unproductive training session – this is ‘junk’ mileage.

  • Avoid sudden / extreme changes in terrain: it is better to expose yourself to change

      in short bouts and build gradually.Manage change of foot wear: break-in new shoes

      in. Wear them indoors and / or for few hours at a time outdoors (not running initially)

      so your feet can get used to the change. Then walk, followed by a couple of short

      runs (5k) to get a better idea how they feel on your feet. If there is no negative

      change in [foot] feeling, then you are good to go…

  • Avoid making too many simultaneous changes to training: this could overload your

      muscles and cause Delayed Onset Muscle Soreness (DOMS) which, without rest, or ‘taking it easy’ until the soreness has dissipated                  (typically 48-72hrs), could add further stress to already damaged soft tissues, increasing the risk of injury. Too much simultaneous change            will also make it difficult to know which component or components of training change made the beneficial improvements or led to discomfort        and / or injury.

  • Seek advice from a coach / personal trainer: coaches support athletes by ensuring

      appropriate progression of exercises, training loads, and rest periods. They can

      provide Individualised training programs designed to allow your muscles to heal

      properly, minimising the risk of some of the more common types of injury.

  • Warm-up and cool down: Prepare your body and mind for what is to come. Allowing the body

      to adjust to stresses gently and progressively enables the body to get the most from training,

      lessening the chances of injury, particularly during blocks of training when fatigue levels are

      at their highest. Cooling down by gently decreasing loading helps the body to return to a calm

      steady state, removing any build up of lactic acid and restoring muscle length by gently

      stretching the worked muscles.

  • Stick to purpose of the session to achieve your session goals: avoid adding to sessions just because you are feeling especially strong. Successful training is about progression: overloading a particular session may affect the outcome of future sessions and accelerate

       fatigue levels.


If you would like to know more about how to improve your training and rid those worrisome niggles, please do get in touch by visiting my website: or my Facebook page:

Laura Fleshman (Runners World)

bottom of page