Strength training consists of exercises designed to increase muscular strength and physical performance. This type of training offers benefits such as improving body composition, increasing bone density and promoting metabolic health. The origins of strength training date back to ancient times in history, and it became modernised in the 19th and 20th centuries. Physiological bases such as neuromuscular adaptations, muscle hypertrophy and hormonal changes ensure that the training process is effective. Factors such as the involvement of motor units and speed coding are critical for performance improvement. Nowadays, modern approaches such as speed-based training, blood flow restriction and functional strength training are used and effective results are obtained in rehabilitation processes. Basic principles such as overload, specificity, adaptation and periodisation guide the design of effective training programmes. As a result, strength training not only improves the performance of athletes, but also provides general health gains. More effective results are achieved through programmes tailored to the needs of individuals and technological innovations. Continued scientific research in this field will make significant contributions to the development of strength training.