Factors Affecting Strength

The ability to develop strength is underpinned by both morphological and neural factors. Understanding these factors can help coaches optimise training strategies that are individualised to the athlete’s specific needs.

Morphological Factors

Muscle Cross-Sectional Area (CSA):

Muscle size plays a key role in contributing to higher strength levels. The greater the size of the muscle, the greater the number of contractile units (sarcomeres) arranged in parallel, which subsequently allows for greater capacity to produce force. 

Muscle Fiber Type:

Muscle fibres are made up of either Type I or Type II, with fast-twitch Type II fibres being larger, having the ability to contract more quickly and produce more force compared to slow-twitch Type I fibres. Players with a higher proportion of fast-twitch fibres can produce more force quickly and tend to excel in explosive movements such as sprinting and jumping. The distribution of fibre types is largely genetic; however, strength training can enhance the recruitment and efficiency of fast-twitch fibres, allowing players to maximise their performance.

Tendon Properties:

Tendons connect muscle to bone and play a key role in transferring the force produced by muscles. Tendon stiffness refers to the tendon’s ability to resist stretching, with stiffer tendons being able to transmit force more efficiently and quickly during movements like sprinting, accelerating and changing direction.

Neural Factors

Motor Unit Recruitment: 

A motor unit consists of a motor neuron and the muscle fibres that it controls. The ability to recruit more motor units during a muscle contraction leads to greater force production. Strength training can improve the ability to recruit more motor units, with early gains in strength during training typically due to improvements in the nervous system’s ability to recruit more motor units rather than any morphological changes.

Motor Unit Synchronisation:

The ability to activate multiple motor units simultaneously and in a coordinated manner, leading to a stronger and more forceful muscle contraction. Strength training can improve this synchronisation, leading to better overall neuromuscular coordination and athletic performance.