AMBULATION & GAIT

1. AMBULATION & GAIT Human Gross Anatomy David G. Greathouse, PhD, PT, ECS November 2, 2004

2. Objectives • Define and describe the components of the gait cycle. • Describe the kinematics of the pelvis, hip, knee and ankle during the gait cycle. • Describe the muscular activity and actions produced by the muscles of the LE during gait. • Discuss the pathokinesiology of the following gait impairments: Gluteus medius muscle weakness, anterior leg compartment syndrome (“foot drop”), posterior leg compartment syndrome, and antalgic patterns - lower extremity and trunk-spine.

3. Gait • Normal human gait repeats a basic sequence of limb motions that serve to progress the body along a desired path while maintaining weight-bearing stability, conserving energy, and absorbing the shock of floor impact. Rancho Los Amigos National Rehab Center

4. Gait - Definitions • Gait - manner or style of walking • Gait cycle – beginning of a walking event by one limb and continuing until the event is repeated again with the same limb • time from heel strike to the next ipsilateral heel strike • Stride - one complete gait cycle • Step - beginning of an event by one limb until the beginning of the same event with the contralateral limb

5. Phases of Gait Cycle

6. Gait Cycle • Swing phase - during the walking cycle, a given foot is in the air, toe-off to heel stride, 38% (ordinary walking) • Stance phase - during a walking cycle, a given foot is in contact with the ground, heel-strike to toe-off, 62% (ordinary walking)

7. Definitions (cont) • Duration of the gait cycle - for any one limb extends from the time the heel contacts the ground until the same heel contacts the ground again • Heel-strike (HS) or heel-on - heel contacts the ground • Toe-off (TO) - toes leaving the ground

8. Definitions (cont) • Speed of locomotion - steps per minute or meters per second • Cadence - number of steps completed per unit of time (steps/min) • Typical gait cycle - 1 to 2 seconds (82 m/min, 113 steps/min, 3 miles/hr) • Double support - both limbs are in stance phase at the same time

9. Eccentric Contraction • Muscles operate eccentrically to either dissipate energy for decelerating the body or to store elastic recoil energy for a shortening (concentric) contraction.

10. Running • Double support no longer present • Both feet off ground for brief time

11. Subphases Stance Phase • Initial Contact (IC) • The moment when the foot contacts the ground, heel strike (heel strike) • Loading response (LR) • The weight is rapidly transferred onto the outstretched limb, the first period of double-limb support (foot flat) • Midstance (MSt) • The body progresses over a single, stable limb • Terminal Stance (TSt) • Progression over the stance limb continues. The body moves ahead of the limb and weight is transferred onto the forefoot • Pre-Swing (PSw) • A rapid unloading of the limb occurs as weight is transferred onto the forefoot (toe-off)

12. Subphases of Swing Phase • Initial swing (ISw) • The thigh begins to advance as the foot comes up from the floor. • Midswing (MSw) • The thigh continues to advance as the knee begins to extend; the foot clears the ground. • Terminal Swing (TSw) • The knee extends; the limb prepares to contact the ground for Initial Contact.

13. Gait Cycle

14. Gait Cycle – Functional Tasks • Weight Acceptance (WA) • This is the period when weight is rapidly loaded on the outstretched limb. The impact of the floor-reaction force is absorbed and the body continues in a forward path while stability is maintained. (Initial Contact and Loading Response) • Single Limb Support (SLS) • Is the period when the body progresses over a single, stable limb. Weight is transferred onto the metatarsal heads and the heel comes off the ground. (Mid Stance and Terminal Stance) • Swing Limb Advancement (SLA) • Is the time when the limb is unloaded and the foot comes off the ground. The limb is moved from behind to in front of the body, reaching to take the next step. (Pre-Swing, Initial Swing, Mid Swing and Terminal Swing)

15. Phases Function

16. Kinematics of the Gait Cycle • A = Sagittal plane • B = Frontal plane • C = Horizontal plane

17. Muscle Activity in the Gait Cycle HS FF HO TO Eccentric Concentric

18. Muscle Activity in the Gait Cycle • Pretibial Muscles • Anterior tibial, EDL, EHL • Prior to and during heel strike • Eccentric contraction - lowers foot to the ground • Prior to and during preswing • Concentric contraction – DF foot, clear toes off ground • Calf Muscles • Gastrocs, Soleus (FDL, FHL, Posterior tibial) • Foot flat • Eccentric contraction - control of tibia over the foot • Heel off • Concentric contraction – ankle plantarflexion

19. Muscle Activity in the Gait Cycle • Quadriceps • Vastus medialis/lateralis/intermedius, RF • Before Heel Strike • Concentric contraction – initiate knee extension • Swing phase • Eccentric contraction – slow down leg (tibia) • Hamstrings • Biceps, Semitendinosus, Semimembranosus • Heel strike • Eccentric contraction - HS peaks – protects knee from hyperextension • Swing phase • Concentric contraction – knee flexion, hip extension

20. Muscle Activity in the Gait Cycle • Hip Abductors • Gluteus medius, Gluteus minimus, TFL • Stance phase • Concentric contraction - stabilize pelvis • Hip Adductors • Adductor longus/brevis, Gracilis, Adductor magnus (horizontal and vertical heads) • Early and late stance • Concentric contraction –stabilize pelvis

21. Muscle Activity in the Gait Cycle • Gluteus Maximus • Stance phase • Eccentric contraction – decelerate forward momentum • Pre-Swing phase • Concentric contraction – hip extension • Erector Spinae • Heel strike through Toe-off • Maintain trunk posture

22. Muscle Activity in the Gait Cycle • Fibularis longus and brevis • Stance phase • Concentric contraction – maintain medial and lateral stability of the foot • Foot Intrinsics • Stance phase • Concentric contraction – support plantar fascia

24. Gluteus Medius Muscle Weakness • Etiology - L4/L5/S1, Sup gluteal n, polio, post-surgery, amputee (prosthetics) • Support effect of muscle on pelvis is lost • Right gluteus medius muscle out • Stance phase on RLE - Left pelvis drops (Trendelenberg - uncompensated) • Compensated - trunk laterally leans to R • Circumduction – leg swings in arc fashion

25. Anterior Leg Compartment Weakness • Foot drop • Etiology - L4/L5/S1, Common or Deep Fibular (Peroneal) nerve - Dislocation of fibular head, Ant compartment syndrome, SLWC tight • Loss of DF of foot • High stepping gait, foot “slap”

26. Posterior Compartment of the Leg Weakness • Etiology - Tibial n injury, L5/S1/S2 • Paralysis of PF of the foot or intrinsics • Unable to PF foot or flex toes, no toe-off

27. Antalgic Patterns of the LE • Ortho or musculoskeletal dysfunctions • Pain in any or all joints in the LE • Changes in gait kinematics, stride parameters, and temporal sequencing • Rate of loading will be decreased - Partial Weight Bearing • OA of the hip, knee joint injury, ankle injury

28. Antalgic Patterns of the Trunk • HNP • Forward bend (Flex) - Backward bend (Ext) • Sidebending - lateral bending

29. QUESTIONS ?