Characteristics of isometric contractions include all but:
a. Shortening
b. Increased muscle tension throughout the contraction phase
c. Absence of shortening
d. Used in resistance training

Verified step by step guidance

1. Step 1: Understand the definition of an isometric contraction. In an isometric contraction, the muscle generates tension without changing its length, meaning there is no visible shortening or lengthening of the muscle fibers.
2. Step 2: Analyze each option in the context of isometric contractions. Option (a) states 'Shortening,' which contradicts the definition because isometric contractions do not involve muscle shortening.
3. Step 3: Consider option (b) 'Increased muscle tension throughout the contraction phase.' This is true for isometric contractions, as the muscle tension increases while the length remains constant.
4. Step 4: Evaluate option (c) 'Absence of shortening.' This aligns with the definition of isometric contractions, where the muscle length stays the same.
5. Step 5: Review option (d) 'Used in resistance training.' Isometric exercises are commonly used in resistance training to build strength without joint movement, so this is also true.

Key Concepts

Isometric Contraction

Isometric contraction occurs when muscle tension increases but the muscle length remains constant, meaning there is no visible shortening or lengthening of the muscle during the contraction.

Muscle Tension During Contraction

During isometric contractions, muscle tension rises and is maintained without changing muscle length, which differs from isotonic contractions where muscle length changes while tension may vary.

Applications of Isometric Contractions in Training

Isometric exercises are commonly used in resistance training to improve strength and stability by holding muscles in a fixed position against resistance without movement.