Research watch

Reference
Folland JP and Williams AG. The Adaptations to Strength Training: Morphological and Neurological Contributions to Increased Strength. Sports Med 2007;2:145-168

Abstract
High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed.The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons.Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability.The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.

My Thoughts
While I try to maintain a somewhat up to date coverage of most published peer-reviewed research surrounding strength training, it is difficult. Review papers such as this one by Folland and Williams provide a nice coverage of the concepts underlying the development of strength.

I especially liked the section entitled "Indirect Evidence of Neural Adaptations, Learning and Coordination"

The authors comment on the observation that increases in dynamic strength (1 Rep max) are disproportionately greater than the gains in isometric strength. This indicates that performing a 1RM is more than just strength, but the ability to display the muscles maximal force potential, in a coordinated effort of the agonist and antagonist muscle groups. This effect can even been seen on relatively simple single joint movements. These neural adaptations are highlighted in a section highlighting Imagined Contractions and their ability to increase strength gains. Going through a lift in the mind has long been a method, for good or bad, used by lifters to help with the big lift. I generally perform the desired movement pattern during the day (bench), it started with the "Grease the Groove" concept by Pavel Tsatsouline, but now its just a habit.