Development of Human Locomotion: From Crawling to Advanced Skills

Early Walking: Prioritizing Stability

When children first begin to walk, their primary goal is to stay upright. To maximize stability and balance, they adopt several characteristic features:

• Arm Position: Arms are held in an abduction position (held out to the sides) to act as stabilizers.
• Base of Support: Feet are placed wide and spread apart to create a larger foundation.
• Trunk and Stride: Trunk rotation is minimal, and the individual takes very short steps.

Proficient Walking: Prioritizing Mobility

As walking becomes proficient, the individual "trades" some of that excess stability for increased mobility and efficiency. This results in a more streamlined gait pattern:

• Stride and Step: Stride length increases while step width is reduced.
• Coordination: Trunk rotation increases, and a rhythmic arm swing (moving arms in coordination with the legs) is adopted.

Exam Tip: If a question asks about the primary difference between early and proficient walking, remember the trade-off: Early walking maximizes stability (wide base, abducted arms), while proficient walking maximizes mobility (narrower base, increased stride, and arm swing).

Developmental Changes in Youth and Adulthood

Locomotion does not stop evolving once a pattern becomes "proficient." It continues to change through various life stages due to physical growth and, eventually, biological aging.

Youthful Progression

In early childhood, the essential components of an advanced walk begin to emerge. We see an increase in speed and an increase in the duration of the stance leg (the period the foot stays on the ground). By mid-adolescence, walking speed increases further, driven by a fuller range of motion and the lengthening of the limbs. At this stage, improvements in the walking pattern become more subtle as the individual reaches a peak level of efficiency.

Aging and the Return to Stability

In older adulthood, the developmental trajectory shifts again. Rather than moving toward greater mobility, the pattern regresses toward maximizing stability over mobility. This is often due to rate controllers such as muscle loss, decreased flexibility, reduced bone density, or slower nervous system responses.

Common characteristics of walking in older adults include:

• A wider base of support and increased step width.
• Decreased stride length and decreased speed.
• Decreased trunk rotation.
• The use of objects (like canes or furniture) as balance aids.

Advanced Locomotion: Running, Jumping, and Hopping

Beyond walking, humans develop more explosive and complex locomotor skills.

Running

Running typically emerges 6 to 7 months after walking. Unlike walking, running includes a distinct flight phase where neither foot is in contact with the ground.

• Early Running: Characterized by arms held in a guard position, limited trunk rotation, and a lack of leg strength/balance.
• Proficient Running: Characterized by increased stride length, arm movement in the sagittal plane (moving forward and backward), and coordination between arms and legs.

Jumping, Hopping, and Leaping

These skills involve more intense force production and specialized mechanics:

• Jumping: Propelling the self off the ground with one or two feet and landing on two feet. Proficient jumpers use a preparatory "crouch" to maximize force at takeoff.
• Hopping: Propelling the self off one foot and landing on that same foot. This requires significant postural control to balance on a single limb.
• Leaping: Propelling the self off one foot and landing on the opposite foot.

Complex Patterns: Galloping, Sliding, and Skipping

These skills are combinations of simpler movements:

• Galloping and Sliding: These are asymmetric patterns. Galloping involves a forward step and a leap, while sliding is a sideways version of the same movement.
• Skipping: This is a symmetric, complex pattern involving alternating step-hops on each foot. Skipping is usually the last of these to emerge, typically appearing between ages 4 and 7.

Assessment: The TGMD-3

To measure these skills in a clinical or educational setting, practitioners often use the Test of Gross Motor Development, Third Edition (TGMD-3).

The TGMD-3 includes a locomotor subscale that assesses specific skills: running, galloping, hopping, skipping, jumping, and sliding. The assessment process follows a standardized protocol:

1. A demonstration of the skill is provided.
2. The individual performs one practice trial.
3. The individual performs two scored trials.

Each skill is evaluated based on 3 to 5 specific performance criteria. The scores from these skills are summed to provide a total locomotor score out of 46.

Summary Table: Locomotor Skill Progression