10 % Rule!

What is it and how can it help you?




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

a) the effects of training on the body

b) how the 10%rule can help you get more from your training

c) how the 10% rule can help to reduce the risks of injury


The 3 most common causes of suffering unnecessary injury are:


a) returning back to training too soon after illness or injury

b) ramping up training too quickly, and/or

c) 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.:


a) doing too much too soon

b) over training; and

c) increasing the risk of being injured



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


a) Training overload

b) 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 http://www.physicallytrained.com/1-4-fitt-factors/ or https://www.sport-fitness-advisor.com/fitt-principle.html). 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 fitness.



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. (Image by Laura Fleshman - Runners World)


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