Fundamental Principles for Strength Training

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Fundamental Principles for Strength Training

When designing a strength training program, a number of fundamental principles provide the basis for designing an appropriate workout program that maximizes potential for strength gains.

Individualization (Principle of training) is key to formulating training goals that are matched to each person's needs. Pretraining (baseline) testing information is needed to monitor the training goal, optimize progression, and evaluate the success of the exercise prescription. Frequently, training time is wasted if baseline information is lacking. The baseline information could be things such as a movement screening protocol or gaining existing strength data so that loads can be calculated.

Optimal training programs are designed to meet realistic, specific, and individualized goals. The magnitude and rate of improvement observed with training depend on genetic endowment, training status (i.e., how much prior strength training has been performed), and effectiveness of the exercise prescription. One factor often overlooked is Chronological Age versus Training Age. This is important as you may have a 30year old novice lifter and an 18year old relatively experienced lifter. These factors pose potential programming issues.

Therefore, expectations for improvements must be framed within the physiologic context that each person brings to the training program. Finally, training programs must change as program goals are attained, and this makes exercise prescription a dynamic process. This is obviously linked with the Progression / Overload section discussed later.

Specificity (Principle of training) is one of the fundamental principles in all training not just strength training. It can if done correctly have a dramatic influence on almost all exercise responses and training adaptations. This is an area that poor coaching and a lack of understanding by the athlete can seriously hinder the degree of gains and benefits achieved.

Whilst working with an elite table tennis player, her previous conditioning coach had her doing 30minute steady state cardiovascular workouts on a treadmill. Table tennis players NEVER run in a straight line, or perform at a steady heart rate. The sport is typified by intense bursts of activity with multi-directional movements that take place within a relatively small space. Hopefully from this example, you can see how important Specificity is in program design.

A high degree of task specificity is involved in human movement, acute physiologic responses, and chronic adaptations to exercise. The specific exercise stimulus is related to the:

• muscle actions involved
• speed of movement
• range of motion
• muscle groups trained
• energy systems involved
• intensity and volume of training.

Although there are some general carryover effects, most of the chronic adaptations are specific to the exercise stimuli used. Effective strength training programs are designed to stimulate muscles in a specific manner related to these different variables (1).

Recruitment of motor units depends on the magnitude of the external resistance used in an exercise. Aerobic exercise is performed by motor units composed of type 1 (slow-twitch) muscle fibers. Heavier resistances will also recruit motor units made up of type 2 (fast-twitch) muscle fibers. The greater the resistance used, the greater the need for more muscle tissue to be activated; therefore, a training program uses heavy loading to activate all of the muscle tissue in a specific exercise.

Progressive overload (Principle of training) refers to the need for heavier resistances to stimulate continued adaptation and improved force production. The body has an innate ability to adapt to stressors quite quickly so progressive overload, whilst maintaining technique is very important to implement.

Progressive resistance exercise is a classic principle that was established by the research of DeLorme and Watkins (2, 3). After World War II, they demonstrated the importance of progressive resistance exercise for increasing muscle strength in the physical rehabilitation of military casualties.
Physiologic demands in a strength training program can be increased in several ways (4).

The load (resistance), number of sets (completion of an exercise to its RM constitutes a single set), or volume of exercise may all be increased. The repetition speed can be altered with sub-maximal loads according to goals. Rest periods may be lengthened to enhance force production in strength and power training or reduced to improve local muscle endurance. Optimal results in a training program depend on proper management of the progression of physical demands.

Repetition maximum allows the prescription of a targeted number of repetitions for each exercise. This can be prescribed after the accumulation of baseline data about the athlete. The external resistance at which an individual can perform only one repetition, but not two, is the 1 RM. RM also refers to other specific numbers of repetitions limited by a specific resistance (e.g., 5 RM, 10 RM, 15 RM). The resistance that limits the individual to 10 repetitions is the 10 RM. As resistance increases, fewer repetitions can be performed (figure 2). As the athlete gets stronger, the resistance seems lighter, and the number of repetitions will increase. The RM system has been used for more than 50 years to prescribe resistance exercise intensity (2, 3).

More than 20 years ago, Atha's literature review established that heavier resistances result in greater strength development than lighter resistances. Thus, the RM continuum is associated with the expected gains made in 1-RM strength development. Prescription of resistance can therefore be tied to an RM target (e.g., 12 RM) or, in more practical terms, an RM training zone (e.g., 8 to 10 RM).

The resistance used in each set and the number of repetitions performed are recorded to establish the amount of weight used in each workout. As the strength of the lifter gradually increases over time, the resistance is adjusted so that either a true RM target or RM training zone resistance is used. An RM training zone consists of a three-repetition range (e.g., 8 to 10 RM). This approach reduces the need to exercise to failure on every set, which can create additional stress (e.g., joint compression and soreness), especially among the older patient population.

One important consideration is that novice lifters usually experience a high % gain in strength in the first few weeks of lifting. This is down to increased neural control (mind to muscle connection), more efficient firing of the motor neurons and improved technique and understanding. Therefore progressions should not be implemented too soon at this early stage as the muscle and connective tissues will have not hypertrophied sufficiently as the gains are more neural than tissue based.

Variation means that the resistance starts out light as in the case of Anatomical Adaptation, with the volume of exercise high, and systematically progresses over time to heavier resistances with lower volumes. Periodization means that the volume of the training stimulus and intensity of training vary, and planned rest periods are incorporated.

Using periodization successfully in strength training programs has underscored the importance of variation in training stimuli. Planned periods of rest to enhance recovery and eliminate any possible overtraining are a key component in periodization theory and allow the lifter to remain ‘fresh’ both physically and mentally. Neural fatigue can be quite high when dealing with maximal and sub-maximal strength training.

Creating a Workout

A workout comprises a selected combination of variables that produce a specific exercise stimulus. Termed the "acute program variables," the choices made for each variable define the physiologic demands of the workout. The training adaptations that occur will be specific to the choices made for each variable.

Choice of exercise. Typically matched to the biomechanical characteristics of each sports-related skill, the choice of exercise is determined by the need to:

• Use each of the major muscle groups (e.g., legs, thighs, lower back, abdomen, chest, upper back, shoulders, and arms);
• Exercise both sides of each joint; and
• Include structural closed–kinetic-chain, whole-body exercises (e.g., squats).

It is especially important to include structural multiple-joint exercises in a strength training program, because most sports and functional activities in everyday life depend on such movements. The use of concentric (i.e., shortening muscle), eccentric (i.e., forced stretch), and isometric (i.e., unchanged length) muscle actions in resistance training will yield different adaptations. However, greater improvements can be made when a repetition includes both the concentric and eccentric components.

The equipment used can also dictate how the muscles are trained and the type of muscle action used. The choice of exercise must address the principle of specificity of training for the greatest carryover to targeted goals (e.g., power requires explosive training with whole-body movements, such as power cleans) for enhanced physical development and performance (1).

Sequence of exercise. The order in which exercises are performed during a workout affects muscle fatigue. Exercising the larger muscle groups first allows the use of heavier resistance in a given exercise. Working the large muscle groups before the small muscle groups creates a more effective training stimulus for strength development. Also any explosive, power exercise such as plyometrics, sprints or Olympic lifts should be scheduled first in the workout after an appropriate warm up has been carried out.

The sequence of exercises will affect the intensity used during the workout. It is also based on individual training goals and is highly dependent on energy metabolism and the amount of fatigue that is acceptable in a given workout. Therefore, exercise order needs to correspond to the training status and training goals of the individual. When the intensity is important, the large-muscle-group exercises must be placed early in the workout sequence.

Number of sets. First, not all exercises in a training session need to be performed for the same number of sets. The number of sets and repetitions are two of the factors in any volume of exercise equation.

The majority of evidence indicates that multiple-set systems work best for the development of strength and local muscle endurance. No study has shown that single-set training is superior to multiple-set training in either trained or untrained individuals despite its advocates such as Dorian Yates and the late Mike Mentzer.

It appears that, while both programs may be similar for increasing strength in untrained subjects during short-term training periods (6 to 12 weeks), multiple-set systems are required for optimal progress over longer training periods. The amount of sets used is an obvious way that a Periodized program can be adjusted.

However, the need for variation also becomes critical for continued improvement, and lower-volume training programs can be used for certain phases of the overall training cycle. The key factor is the periodization of training volume rather than the number of sets, which are only one factor in a volume and intensity periodization model.

The importance of the exercise volume (sets, repetitions and intensity) is a vital concept of training progression (4). This is especially true in individuals who have already achieved a basic level of strength fitness. The interaction of the number of sets with the principle of variation in training or, more specifically, periodized training, may also help augment an individual's training adaptations.

Rest periods. The influence of rest periods on the stress of the workout and the amount of resistance that can be used for an exercise has been a topic of study for the past 15 years. Rest periods between sets and exercises determine how much of the adenosine triphosphate/creatine phosphate energy source is resynthesized and how high lactic acid concentrations become in the muscles and blood.

The length of the rest period significantly influences the metabolic, hormonal, and cardiovascular responses to an acute bout of resistance exercise, as well as performance of subsequent sets (1). Lactate and hydrogen ion concentrations (decreasing ph value > becoming more acidic) dramatically contribute to muscle fatigue and loss of force-production capabilities.

Rest periods span a continuum from very short to long. When training for absolute strength or power, rest periods of at least 3 to 5 minutes are recommended. Shorter rest periods (less than 2 minutes) produce dramatic increases in muscle and blood lactic acid levels and perceptions of fatigue. Olympic lifters and sprinters often sit down between sets to maximize ATP resynthesis.

Typically rest periods between sets follow this general rule:

1. 1-4 reps/set = 3 or more minutes of rest between sets.
2. 4-8 reps/set = 2.5-3 minutes rest between sets.
3. 8-12 reps/set = 2 minutes rest between sets.
4. 12-15 reps/set = 90 seconds rest between sets.
5. 15-20 reps/set = 60 seconds rest between sets.
6. 20-25 reps/set = 30-45 seconds rest between sets.

Incorporating gradual reductions in rest periods in a strength training program requires about 6 to 8 weeks to improve tolerance to high muscle and blood lactate concentrations, improve local muscle endurance, and stimulate anabolic hormones. If such adaptations are vital to a sport (e.g., wrestling or 400- to 800-m track events), the length of rest periods between sets and exercises in training may enhance performance in those sports. Careful manipulation of rest periods is essential to avoid needless stress during training.

Intensity - The amount of resistance used for a specific exercise is one of the key variables in any strength training program. Again, using either the RM or RM training zone is probably the easiest method for determining the correct resistance. Some exercises (e.g., power cleans) that rely on recruitment of many muscles across several joints are better suited to using a percent of the 1 RM.

The repetition continuum from heavy resistances to lighter resistances allows one to predict the primary training outcome based on the intensity used. It appears that RM resistances of 6 or less have the greatest effect on muscle size, strength, and power, and those of 20 or more show the greatest effect on muscle endurance. This continuum makes it possible to develop a particular feature of muscle performance to varying degrees over a range of RM resistances.

Strength Training Summary

Anaerobic exercise, performed with high resistance, develops strength and explosive power. An exercise prescription for strength training is based on scientific principles and decisions about individual responses and quantifiable data (e.g., baseline testing, training logs, and subsequent evaluation). An effective program is individualized, engages multiple joints, and measures progress toward meeting both the demands of a sport and the goals of the individual.

The development of a periodized training program starts with the design of each workout by selecting the appropriate exercise stimuli and sequence of the acute program variables. Effective training over time requires variation in the exercise stimuli as well as planned periods of rest and recovery. By following the Principles of Training a coach or athlete can maximize strength gains whilst minimizing the potential for injury and unproductive time.

References

(1) Fleck, S.J., Kraemer, W.J: Designing Resistance Training Programs, ed 2. Champaign, IL, Human Kinetics Publishers, 1997.

(2) Kraemer, W.J., Adams, K., Cafarelli, E., et al: American College of Sports Medicine position stand: Progression models in resistance training for healthy adults. Med Sci Sports. Exerc 2002;34(2):364-380.

(3) Marx, J.O., Ratamess, N.A, Nindl, B.C., et al: Low-volume circuit versus high-volume periodized resistance training in women. Med Sci Sports Exerc. 2001;33(4):635-643.

(4) Kraemer, W.J, Häkkinen. K (eds): Strength Training for Sport. Oxford, England, Blackwell Science, 2002, pp 1-186.