Presentation on theme: "Analysis of a continuous skill – walking and running (gait)"— Presentation transcript:
1 Analysis of a continuous skill – walking and running (gait) Reading assignment:Jones & Barker, Ch 15; McNeil, Ch 5OutlineWalkingGait cycleKinematics and ground reaction forcesRunningMethods of studying gaitGait changes with children and ageing
2 Walking Analysis … the process A gait cycle consists of “the activities that occur from the point of initial contact of one lower extremity to the point at which the same extremity contacts the ground again”During one gait cycle, each extremity passes through two phases, a single stance phase and a single swing phase.
5 Components of the Stance Phase Stance phase comprises 60% of the gait cycleHeel strike – moment when the heel first strikes the groundFoot flat – from heel strike to when the full foot is in contact with the groundMidstance – body weight is directly over the stance legHeel off – moment the heel of the stance leg leaves the groundToe off – when only the toe of the stance leg is in contact with the ground
7 Components of the Swing Phase Swing phase comprises 40% of the gait cycleAcceleration – the toe of the stance leg leaves the ground and begins to swing forwardMidswing – the swinging leg is directly beneath the bodyDeceleration – the swinging leg continues forward towards knee extension but is slowing down as it travels, stopping just prior to full knee extension and heel contact with the ground
15 Range of motion at the joints Trunk - As left leg moves forward, pelvis rotates clockwise as viewed from above 7 degHip Joint (30 deg flex at HS strike, 180 deg at TO)Stance - extension, adduction, internal rotationSwing - flexion/extension, abduction, ext rotationKnee joint deg at HS, 160 deg at mid-stanceAnkle joint - Neutral at HS, hinges down during support, and plantar flexes at TO . ROM 30 degCOM displacement +5 cm bilaterally and vertically (Note: Frankel and Nordin state that normal values are + 4 cm bilatgerally and +3 cm vertically)
17 Running Analysis…...Running is similar to walking BUT, it differs significantly in a number of ways, for example:No period of “double support”Float periods (both feet airborne)Requires greater balanceRequires greater strengthRequires greater ROM at hip, knee, and ankle jointsInvolves greater excursion of center of massInvolves greater ground reaction forces
19 Muscle Activity in Running... Glut. Max. & med. -- active at the beginning of the stance phase (concentrically) and again at the end of the swing phase (eccentrically).Iliopsoas -- active during a portion of the swing phase (concentrically).Quadriceps -- 1st 10% of the stance phase (eccentrically) and last 20% of the swing phase (concentrically).Hamstrings -- initial portion of the swing phase (concentric) and at the end of the swing phase (eccentric).Plantar flexors (gastrocnemius & soleus) – Mid and latter part of stance phase
20 Methods of Studying Gait Observational techniques (use checklist, and videotape when possible)(Slide 18)Quantitative analysistime-distance measurements (stop watch, footswitches) (Slide 19)Kinetic techniques (Slide 20)Kinematic analysisVideotaping, semi-automated imaging (Slides 21 & 22)Combined kinematic and kinetic (Slides 20 & 21)
29 Gait changes with normal ageing Generally, they try to improve stability by the following adjustments:Shorter step and stride lengthslower walking speedsgreater variation in stride widthwider base of support
30 Gait in children base is wider until 4 yrs no heel strike until 2 yrs - contact is made with a flat footstride length and velocity is lesscadence is greaterreduced knee flexion in stance phase until 2 yrs of ageno reciprocal arm swing until 4 yrsadult stride length, velocity & cadence are obtained around 15 yrs of age
31 Scientific Method of Problem Solving Develop (define and delimit) the problemFormulate the general hypothesis:Overload training improves strength(e.g., 3 sets of bp 3 d/w will improve bp strength)Formulate the specific hypothesis:If A (general) is true, then B (specific) will be true(e.g., if the general hyp is true, then posttest > pretest)Gather , analyze, and interpret the dataIf B is true (significant difference), what about A?If B is not true (no sig diff), what about A?Discuss the resultsIs B without A very unlikely, or are there alternative explanations?