Velocity based training is another within?session method of monitoring that has grown increasingly popular as the technology for monitoring repetition velocity in the clinic or gym has become available. Research at this point is still emerging but a few practical models have been developed that determine intensity based on the velocity of the bar during the lift and the end of the set being based on a predetermined decrease in velocity.76 When applied systematically this approach allows for immediate feedback, fatigue control, prediction and monitoring of biomotor changes, and a guide to the training process.77 To the authors’ knowledge, velocity?based training has not been studied in rehabilitative literature to date.
Strength should be considered fundamental to all other aspects of training and forms the foundation of most successful return to play (RTP) approaches.78 Strength is defined as the ability to produce force68 and is traditionally measured with a single repetition maximum (RM) or by taking a percentage of RM to failure with the RM calculated based on a percentage table. Strength is closely correlated with the capacity to rapidly produce high levels of force and as a result maximal force development should be the initial emphasis with those presenting with lower levels of strength.79–81 The mechanism proposed for this increase in force as a result of strength work has been attributed to increased muscle cross?sectional area and changes in neural drive.79 Exercise intensity or load is commonly accepted as one of the critical components for achieving strength based adaptations. This is fairly well supported in the literature and the common recommendation of loads approximately >80% of RM in trained individuals should build the foundation of most programming for strength.50,82,83
Optimal dosage has been debated, but the evidence to date supports multiple sets over single sets with up to 46% greater strength gains and 40% increase in hypertrophy seen when comparing multiple set to single set approaches in trained and untrained healthy individuals.50,82–85 Peterson also found that three to four sets per exercise with approximately eight sets per muscle group elicited the greatest pre/post effect sizes (standardized mean differences) in strength.84 When multiple sets are not an option, single set training taken to failure is still of a sufficient stimulus to elicit significant changes in strength and hypertrophy.50,82–86
This brief review of strength principles highlighted some of the considerations that the sports rehabilitation professional must consider when programming within any of the periodization schemes. Practical recommendations for strength training loads are presented in Table 7.
Intensity Training Zones104 *All loads expressed as percentage of 1RM
Many aspects of sport and daily life require the ability to produce relatively high levels of force in a brief period of time. This characteristic is commonly described as power although there are some concerns that this term may not be as accurate as the biomechanical term, impulse.87 For the purpose of this paper the term will be used in its commonly accepted definition. Power is defined as the rate at which work is performed and is the product of force and velocity. As a result it becomes apparent that the ability to apply high levels of force in a brief period of time and to contract at high velocities are vital components of its development.88 The importance of power development in the rehabilitation environment ranges from fall risk reduction in the elderly89,90 to returning an athlete to sport post anterior cruciate ligament reconstruction.91 In athletics the ability to produce high power outputs with a high rate of force development has been proposed by Stone et al to be a critical aspect of success in many sports.92 As such an understanding of power development and its integration into a periodization approach is important.