Reasons for strength training include: resistance to osteoporosis and low-back injuries, enhancement of physical capability (including activities of daily living and ability to react to emergency situations), increased metabolic rate for weight control, and improved appearance. 

“Resistance training,” or “strength training,” is a broad term meaning the development of muscular strength and endurance using free weights, machines, stretch bands, or simply body weight. 

Muscular strength is defined as the maximal amount of force a person can apply (usually demonstrated in a single repetition).

 

Muscular endurance is the ability to repeatedly apply a percentage of maximal strength. 

Types of muscle actions (contractions) include: static (tension development with no change in joint angle), and dynamic (tension development with a change in joint angle). Dynamic actions include concentric (muscle shortening) and eccentric (muscle lengthening). Most forms of resistance training involve both shortening and lengthening dynamic muscular movements. 

Eccentric actions occur quite frequently during most human movement. In resistance training, they occur when lowering weight slowly against gravity. They are effective in tension development, (which promotes muscular strength) but also contribute to delayed onset muscular soreness (DOMS).  

DOMS results from training too hard without an initial break-in period, and results in muscular soreness felt 2-3 days after the training session.  

Static actions temporarily increase blood pressure to high levels and may cause abnormal heartbeats if the breath is held during the movement (Valsalva effect). For this reason, dynamic actions without breath holding are preferred for most adults.

Some weight training machines are considered “accommodating or variable resistance,” meaning they are specially designed to vary the resistance, with the goal of creating a more uniform, maximal resistance throughout the full range of movement.

Isokinetic machines are accommodating resistance machines that ensure a constant speed throughout the full range of movement. They are often used in rehabilitation because they may be performed without the eccentric action (which is a necessary part of most other types of resistance training). 

The principles of overload, specificity, reversibility, progression, and overtraining apply to resistance training just as they did to cardiorespiratory training in lesson 3. Additionally, the terms “progressive resistance” (method of progressively or systematically overloading muscle), and “periodization ” (method of cycling through the various stages in training for competition) are often used.

 

There are numerous methods of overloading and progressing in resistance training. General guidelines for busy adults include: using a few basic exercises that involve several muscles in their execution, employ 2-3 sets of 10-12 repetitions per exercise at moderate difficulty, for 15-45 minutes, on 2-3 days per week. A “set” is one series of continuous repetitions. A “repetition” is one execution or lift, from start to finish.

There are many modes of resistance training. The recommended activity for adults engaging in health-related fitness is simply the one that is most convenient, safe and comfortable. This might be free weights, machines, stretch bands, body weight or other activities.

  

Because aerobic training requires from 30-60 minutes per session, the duration of the resistance training session should be kept fairly short (15-45 minutes) in order to keep the total training session within 60 minutes. Incorporating the resistance training fitness component into the workout session may necessitate a shorter duration of aerobic training on strength training days or alternate day training. Remember, keep it short and effective--busy adults normally don’t have time to become “bodybuilders.” Many adults benefit from a 15-20 minute resistance training session at the end of their aerobic workout. 

The frequency of resistance training for health-related fitness should be 2-3 days per week during the improvement stage and 1-2 days per week to maintain.

This is for workouts where the total body is trained in a single session. It is not wise for a busy adult to “split” their strength workout into several sessions unless they are training for performance-related fitness (bodybuilding).

 

Intensity of resistance training is often difficult to monitor since heart rate cannot be used and the RPE scale was designed for steady rate aerobic exercise.  Also, the use of a percentage of a person’s single maximal repetition (% 1RMAX) is not practical for use except with experienced athletes. Normally, an adult should begin training very light during the initial stage, and gradually progress to moderate or moderately-hard at the end of the improvement stage.

 

The following rating of perceived exertion for resistance training (RPER) is easy to use and fairly accurate when used with resistance training:

  

(The link to the RPER scale has not been completed at this time)

 

The initial stage of resistance training should begin with 1 set of 10-12 very light repetitions (1X10 very light), gradually increasing to 2 or 3 sets of 10-12 moderate repetitions (3X10 moderate) during the improvement stage, and 1-3 sets of 10-12 moderate (1-3X10 moderate) repetitions during the maintenance stage.

 

The relationship between sets, repetitions and the amount of weight used is: heavier weight and fewer repetitions to emphasize muscular strength and size;  lighter weight and more repetitions to develop muscular endurance. A good combination for most individuals is 3 sets of 10-12 repetitions for each movement. 

For more specific strength training programs, click on the following:

 

(Specific weight training program guide not completed at this time)  

Resistance training movements should be slow and controlled—breathing out during the execution of the movement, and in on the return to the starting position. A person should continue to breathe during the execution of the movement. The breath should not be held.  

A good rule of thumb is to rest between sets until breathing rate returns almost to normal. Make certain to use a spotter if necessary—never lift heavy weights without a spotter.