Anatomy Sites

BBC - Interactive Body Games
Human Skeleton
Instant Anatomy
How Muscles Work (excellence level)

external image B......... PE Muscles.ppt Classroom Powerpoint on the Action of Muscles in the Human body.

external image muscles.ppt Check out this powerpoint that introduces you to the role and function of the muscles in the body.

Adjusting angle between two parts
Flexion - Bending movement that decreases the angle between two parts. Bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed. Flexion of the hip or shoulder moves the limb forward (towards the anterior side of the body).
Extension - The opposite of flexion; a straightening movement that increases the angle between body parts. In a conventional handshake, the fingers are fully extended. When standing up, the knees are extended. Extension of the hip or shoulder moves the limb backward (towards the posterior side of the body).

Muscle Movement

Muscle contraction is initiated by an electrical charge from the central nervous system. The exercise that causes the greatest amount of electrical activity within the muscle group will potential produce the greatest gains in mass and strength. Lorenzo Cornacchia conducted a series of Electromyographic (EMG) tests to determine which exercises generated a high level of stimulation with in each muscle group. The results were as follows:
Pectoralis Major
Decline dumbbell bench press
Pectoralis Minor
Incline dumbbell bench press
Medial Deltoids
Standing dumbbell side laterals
Posterior Deltoids
Standing dumbbell bent laterals
Anterior deltoids
Standing front dumbbell raises
Biceps Brachii
Incline seated dumbbell curls (alternate)
Triceps Brachii
Triceps press down (angled bar)
Latissimus Dorsi
One arm dumbbell rows (alternate)
Rectus Femoris
Seated leg extensions
Biceps femoris
Standing leg curls
Seated leg curls
Standing one leg calf raises
Table adapted from: Serious Strength Training, Tudor O. Bompa et al. 1998, Human Kinetics,
Table 11.1 IEMG max motor-unit activation

Different strength types and how to train for them

Most sports will require some or all of the following strength types to be developed to one degree or another and the weight training program should reflect this.

Strength Endurance

The aim is to develop muscles that are able to to produce repeated contractions under conditions of fatigue. This requires high repetitions (15+) with light loading (30-50% of 1RM). Appropriate for field sports, rowing and martial arts.


The aim is to develop fast powerful movements. This requires medium number of repetitions (6-10) with medium to heavy loading (70-80% of 1RM). Appropriate for power based events e.g. sprinting, jumping (long jump), throwing (Javelin).

Maximum strength

The aim is to enable maximum loads to be lifted. This requires low number of repetitions (1-5) with heavy loads (80-100% of 1RM). Appropriate for Power Lifting, Olympic Lifting, Shot Putt.

Size with strength

The aim is to increase muscle size. This requires medium to high number of repetitions (8-12) with medium to heavy loading (70-80%+ of 1RM). Appropriate for Bodybuilding or sports like USA football where increased size is a valuable asset.

How Much?

The amount of weight to be used should be based on a percentage of the maximum amount of weight that can be lifted one time, generally referred to as one repetition maximum (1RM). The maximum number of repetitions performed before fatigue prohibits the completion of an additional repetition is a function of the weight used, referred to as repetition maximum (RM), and reflects the intensity of the exercise. A weight load that produces fatigue on the third repetition is termed a three repetition maximum (3RM) and corresponds to approximately 95% of the weight that could be lifted for 1RM.
For maximum results, athletes should train according to their genetic predisposition. An athlete with a greater proportion of slow twitch muscles would adapt better to endurance training and a muscular endurance program using more repetitions of a lighter weight. An athlete with a greater proportion of fast twitch muscles would benefit from sprint training and a muscular strength program using fewer repetitions of a heavier weight. Dr F. Hatfield's Muscle Fibre Test may help you determine your predominate muscle type.

Load - Repetition Relationship

The strength training zone requires you to use loads in the range of 60% to 100% of 1RM. The relationship of percentage loads to number of repetitions (rounded up) to failure is as follows:
% Load

How Many

The number of repetitions performed to fatigue is an important consideration in designing a strength training program. The greatest strength gains appear to result from working with 4-6RM. Increasing this to 12-20RM favours the increase in muscle endurance and mass.
One set of 4-6RM performed 3 days a week is a typical strength training program. The optimal number of sets of an exercise to develop muscle strength remains controversial. In a number of studies comparing multiple set programs to produce greater strength gains than a single set, the majority of studies indicate that there is not a significant difference.
Handling heavy weights in the pursuit of strength will require a recovery of 3-5 minutes between sets, but only minimum recovery should be taken if strength endurance is the aim. The majority of athletic events are fast and dynamic, and therefore this quality must be reflected in the athlete's strength work.
Muscular strength is primarily developed when 8RM or less is used in a set. How much load you use depends upon what it is you wish to develop:
  • 1RM to 3RM - neuromuscular strength
  • 4RM to 6RM - maximum strength by stimulating muscle hypertrophy
  • 6RM to 12RM - muscle size (hypertrophy) with moderate gains in strength (Fleck & Kraemer, 1996)
  • 12RM to 20RM - muscle size and endurance

Rest Interval between sets

The aim of the recovery period between sets is to replenish the stores of Adenosine Triphosphate (ATP) and Creatine Phosphate (CP) in the muscles. An inadequate recovery means more reliance on the Lactic Acid (LA) energy pathway in the next set. Several factors influence the recovery period, including:
  • Type of strength you are developing
  • The load used in the exercise
  • Number of muscle groups used in the exercise
  • Your condition
  • Your weight
A recovery of three to five minutes or longer will allow almost the complete restoration of ATP/CP.