Jens Bangsbo ia a Danish published author on physiology and sport science. He is also a former assistant coach to both Juventus FC and the Danish national football team.

Jens Bangsbo: Fitness Training in Soccer: A Scientific Approach
Jens Bangsbo: Aerobic and Anaerobic Training in Soccer

Jens Bangsbo is one of the most respected names in sports science. In this series of video’s Jens demonstrates a number of drills and practices that can be used to improve the aerobic and anaerobic conditioning of soccer players. Traditionally soccer conditioning was carried out by performing running exercises. However, small sided games offer several potential benefits:

The players improve their tactical and technical skills.
Other physical elements are trained. For instance, small sided games produce many accelerations and decelerations. These are high stress actions that occur in real matches and if players have not been sufficiently exposed to this type of work in training there is an elevated risk of injury.
The work is intermittent in small sided games by which we mean they combine periods of moderate intensity with periods of very high intensity. The ability to handle abrupt changes in aerobic demands may be better trained in small sided games than in isolated running exercises.

When Jens talks about moderate intensity aerobic exercise he is referring to intensities around 75-85% of maximum heart rate(MHR). While for high intensity aerobic exercise he is referring to intensities between 85-95%of maximum heart rate. A general rule for calculating maximum heart rate is 220 – your age.

Aerobic moderate intensity exercise is perfect for building a base of fitness such as in the early preseason. It is also ideal for training following a more intense session where a modes fitness stimulus can be provided while the body recovers from the prior exertions. Many fitness coaches believe that moderate intensity exercise allows for a better removal of metabolites and waste products and hence a better and faster recovery from higher intensity exercise.

1/ Dave Tenney Fitness in Football

a great review of where we stand in terms of research and our knowledge about how to condition the modern soccer player

2/ Raymond Verheijen The Original Guide To Football Periodization

This is not a conditioning book per se as Raymond now eschews sports science terminology but it is a great presentation of a periodized model to develop soccer fitness and minimize injuries.

3/ Javier Mallo Periodization Fitness Training

Ex Real Madrid fitness coach presents his theories concerning tactical and physical periodization along with a library of suggested exercises.

4/ Jens Bangsbo Fitness Training In Soccer: A Scientific Approach

5/ Jens Bangsbo Aerobic and Anaerobic Training Of Players in Soccer: Special Emphasis on Youth Players

6/ Tony Strudwick: Soccer Science

A great review of the whole fitness landscape by the Manchester United conditioning coach through the glorious Ferguson era.

source