Week 4 Typical Development

Question 1

Explain the milestones that characterize postural development and the typical ages they appear.

Answer 1

Head control (2–4 mo), rolling (4–6 mo), sitting (6–8 mo), creeping/crawling (8–10 mo), pull-to-stand/cruising (9–12 mo), independent stance (11–12 mo), walking (12–14 mo). Development follows cephalocaudal/proximal-distal trends but may vary by environment and culture.

Question 2

Differentiate between the reflex/hierarchical and systems theory of developing postural control.

Answer 2

Reflex/Hierarchical: CNS maturation drives reflex integration in fixed order. Systems Theory: Postural control emerges from interactions of sensory, motor, musculoskeletal, and environmental systems, explaining adaptability.

Question 3

Describe the development of head control and independent sitting using a systems framework.

Answer 3

Head control requires visual, vestibular, and somatosensory integration. Sitting progresses from no control → partial → wobbly → functional, requiring trunk strength and balance. Protective and anticipatory responses develop with stability.

Question 4

Describe the development of independent stance and refinement of postural control using a systems framework.

Answer 4

Independent stance (~11–12 mo) requires steady-state, reactive, and anticipatory balance. Refinement includes ankle/hip/stepping strategies, sensory reweighting, and practice-driven adaptations.

Question 5

Describe the emergence of postural control and progression in steady-state gait.

Answer 5

Walking is dynamic postural control with forward COM stabilized by step placement. Emerges from cruising/crawling, improves with practice → longer stride, reduced energy cost.

Question 6

Describe kinematic, kinetic, and EMG changes in gait development.

Answer 6

Kinematics: wide BOS, short steps → narrow BOS, reciprocal arm swing, heel strike. Kinetics: stiff, co-contraction → efficient force generation. EMG: overlapping activity → refined bursts.

Question 7

Describe the 5 characteristics of mature gait.

Answer 7

Reciprocal arm swing, narrow BOS, heel strike, longer stride, smooth pelvic rotation/trunk control.

Question 8

Explain the development sequence for walking.

Answer 8

Early: wide BOS, short steps, high guard arms. Intermediate: better balance, mid-guard arms, longer stride. Mature: reciprocal arm swing, trunk rotation, heel-toe gait.

Question 9

Describe common problems in walking development.

Answer 9

Toe-walking, asymmetry, delayed arm swing, persistent wide BOS; may indicate neuromuscular/orthopedic issues.

Question 10

Describe the emergence of adaptation in locomotion.

Answer 10

Adaptation emerges with varied environments (obstacles, uneven surfaces). Relies on sensory feedback + motor planning, refined by practice.

Question 11

Describe contributions of sensory, motor, and cognitive systems to gait.

Answer 11

Sensory: vision, proprioception, vestibular. Motor: strength, coordination. Cognitive: planning, attention, dual-tasking.

Question 12

Discuss developmental changes in mobility (rolling, prone, supine-to-stand, sit-to-stand).

Answer 12

Rolling: log → segmental. Prone: elbows → pivot → crawl/creep. Supine-to-stand: asymmetric → efficient symmetric rise. Sit-to-stand: wide BOS → smoother transitions.

Question 13

Describe developmental changes in reach/grasp and eye-head coordination.

Answer 13

Eye-head stabilizes first. Reach: jerky → smoother, predictive. Supports exploration and object interaction.

Question 14

Describe changes in reach and manipulation with development.

Answer 14

Early reach: visual, inefficient. Later: proprioceptive control, refined manipulation, bimanual coordination, problem-solving.

Question 15

Describe developmental changes in reach/grasp involving motor and vision.

Answer 15

Motor: improved timing, coordination, anticipatory control. Vision: critical early, later supplemented by somatosensory feedback. By preschool, reach is smooth, fast, less visually dependent.

Question 16

Describe developmental changes in grasp and cognitive components.

Answer 16

Grasp adapts to object/task; cognitive load influences timing/accuracy. Complex tasks integrate memory, planning, adjustment.

Question 17

Describe changes in grasp patterns through development.

Answer 17

Reflexive → palmar → radial digital → pincer (9–12 mo) → refined tool use. Later refinement: precision grips, task adaptation.