ANALYSIS & TRAINING OF AMPUTEES ON

1. S T A I R S ANALYSIS & TRAINING OF AMPUTEES ON

2. Outline • Normal Biomechanics • Differences with Below-Knee Stair Patterns • Implications • Video • Brainstorming! **Consider what muscles / segments are affected in amputee clients during discussion

3. Normal Characteristics • Cadence • Ascent = 82-116 steps/min • Descent = 107-140 steps/min • Shorter women go faster! • Proportions: • Ascent = stance 50-65% • Descent = stance 19-68% • 31% double support

4. Trans-Tibial Amputees • Slower velocity (Powers et al, 1997) • Ascent: 80% of normal • (29.6m/min vs 33.4m/min) • Descent: 84% of normal • (29.6m/min vs 35.2m/min) • Significant stance phase asymmetry, especially single support (decreased 12% ascending, 13% descending).

5. Trans-tibial Amputees • Powers et al (1997) • Decreased velocity indicative of • Limited ability to elevate body mass. • Diminished ability to maintain forward progression. • Diminished single support time is an indication of instability, and difficulty controlling balance.

6. Normals • Large amount of intra-subject variability, but high correlations of certain characteristics between subjects. • Higher the activity in certain muscles, the lower the variability. • Indicates the inherent instability of this task.

7. Stair Ascent • McFadyen & Winter (1988) • Stance • Weight Acceptance (WA) • Pull Up (PU) • Forward Continuance (FCN) • Swing • Foot Clearance (FC) • Foot Placement (FP)

8. Weight Acceptance • Moves body into optimal position to be pulled up onto the step. • Initiated by contralateral plantarflexors. • Involves strong concentric activity of hip & knee extensors. • Ankle moves into ~130 dorsiflexion, with soleus working eccentrically to stop too much knee flexion.

9. Weight Acceptance – BKA’s • Powers et al (1997) • Lengthened “initial double limb support”. • Indicates difficulty transferring weight forwards onto prosthesis. • “Prosthetic DF only capable of ~70 • Yack et al (1999) • Passive properties of prosthesis cannot limit excessive knee flexion like soleus would.

10. Weight Acceptance – BKA’s • Torburn et al (1994) • Increased hip flexion (trunk flexion) to assist moving weight forward over the foot.

11. Pull Up • Most unstable portion – body supported on one limb, while all joints are flexed. • Support moment twice normal gait. • Concentric power generation by VL and plantarflexors (mainly soleus). • Hip moments & power are variable – must control Head/Arms/trunk segment. • Gluteus medius active at beginning of PU, keeping pelvis level during single support.

12. Pull Up – BKA’s • Powers (1997), Yack (1999) & Torburn (1994) • Amputees used a “hip dominant” strategy to raise body weight, rather than “knee strategy”. • Decreased joint moments & powers at knee & ankle. • Increased joint moments, powers, and total work at hip • 20% inc hip extensor work; 40% inc VL work; • Increased & prolonged hamstring contractions • Assist hip extension • Protect distal tibial remnant from pressure on anterior socket. • RF recruited to assist VL.

13. Forward Continuance • The subject has ascended the step, & is moving forward to the next. • Mainly horizontal – no vertical shift of CoM until just prior to toe-off. • Support moment remains extensor, with burst of gatrocs/soleus activity at the end to produce vertical thrust.

14. Forward Continuance – BKA’s • Decreased hip extension range / increased trunk flexion. • No plantarflexion for vertical thrust.

15. Foot Clearance • Involves lifting the leg & clearing the intermediate step. • Involves concentric dorsiflexor activity, then concentric hamstring activity. • Forward & up movement produced by hip flexors (not RF) & contralateral vertical thrust. • Some RF activity to reverse knee flexion & limit heel rise.

16. Foot Clearance – BKA’s • Decreased dorsiflexion range: ~50 • Knee motion not significantly different (Powers et al 1997).

17. Foot Placement • Hamstrings work eccentrically to lower the foot, with simultaneous concentric DF activity. • Final foot position is controlled by hip extensors. • Preparatory activity prior to foot contact in RF, VL, Glut max & glut med.

18. RF VL McFadyen & Winter (1988) Gmax Gmed

19. Other points • Differences from ground to step 1 compared to step1 to step 3. • Two peaks in GRF’s • Start of single limb support = 107%BW • End of FCN corresponding to vertical thrust = 115%BW • No periods of vertical movement without concurrent horizontal movement. • Support moment needing to be generated is 2-3 times that for level walking.

20. Other Points • Need up to 1200 of knee flexion.

21. Points for BKA’s • More prolonged & intense EMG (Powers et al 1997) through stance. • Total combined power generation avg 32% of isometric MMT, vs 23% in normals. • Increased energy expenditure. • Moment & power calculations may be decreased around the knee, as calculations do not account for co-contraction with hamstrings.

22. Descent • McFadyen & Winter (1988) • Stance • Weight Acceptance (WA) • Forward Continuance (FCN) • Controlled Lowering (CL) • Swing • Leg Pull-Through (LP) • Foot Placement (FP)

23. Weight Acceptance • Usually a toe-strike • Dominated by eccentric activity of RF, VL, gastrocs & soleus. • Most energy is absorbed by plantarflexors.

24. Weight Acceptance – BKA’s • Powers et al (1997) • Foot contact in ~ 30 DF, thus no toe-strike, and no energy absorption through PF’s. • Increased Gmax & hamstrings activity to assist weight shift. • ? Softer contact = no momentum, & therefore must actively extend to shift weight. • Decreased knee flexion during WA.

25. Forward Continuance • Extensor moment at all 3 lower limb joints. • Knee extends slightly while moving forwards. • Movement controlled by eccentric plantarflexor activity.

26. Forward Continuance –BKA’s • Prolonged & more intense hip extensor activity.

27. Controlled Lowering • Involves descent to the next step. • Power absorbed by eccentric quads, less so from soleus. • Burst of concentric soleus activity at the end, to relieve the extreme dorsiflexed position. • Hip flexors working concentrically – suggests working to control Head/Arms/Trunk segment rather than assist in the lowering of the body

28. Controlled Lowering – BKA’s • Powers et al (1997) • Decreased knee flexion (170 vs 250). • Decreased ankle DF (100 vs 230). • Increased hip flexion (290 vs 170). • Greater anterior pelvic tilt. • Significant Gmax activity, & prolonged hams activity: • Hip involved in lowering body mass • Hams co-contraction to protect distal tibia from excessive pressure against socket (Yack et al 1999). • RF recruited earlier (late swing) and earlier cessation of activity (16% cycle vs 47% cycle).

29. Leg Pull Through • Hip continues to flex concentrically. • Knee flexion required to clear intermediate step (but not as much as ascent ~1000). • Ankle dorsiflexes concentrically.

30. Foot Placement • Reversal of movement – hip & knee extend, ankle plantarflexes. • Hamstrings decelerate knee extension. • Glut med active just prior to contact – may have been involved in keeping limb abducted as well as preparing for WA. • Tib-Ant contraction just prior to contact to move impact point to outer border of foot. • Gastrocs co-contraction in preparation for impact.

31. Foot placement – BKA’s • No active plantarflexion in preparation for impact.

32. Figure 4: EMG During Descent (McFadyen & Winter, 1988) McFadyen & Winter 1988)

33. Other Points • Differences from step 3 to 1 compared to step 2 to floor. • No vertical movements without concurrent horizontal movements. • Descent speed correlated significantly with cross-sectional area of knee extensors & psoas major – suggests muscle mass plays a role.

34. Other Points • Evidence of preparatory actions in Gmed, Gmax, VL, & gastrocs. • Two peaks in GRF’s: • First at start of WA = 120%BW • Second at end of FCN / start CL = 100%BW • Greater Centre-of-Mass / Centre-of-pressure divergence indicates greater inherent instability in descent – “controlled fall” (Zachazewski et al 1993).

35. Other Points • Use of handrail “in the usual fashion” did not influence flexion/extension moments (Andriacchi et al 1980). • Joint ROM required: • Up to 1000 knee flexion. • Up to 250 ankle dorsiflexion.

36. IMPLICATIONS • Ascent & descent requires up to 1200 knee flexion & 250 dorsiflexion. • Uh oh. • Reduce bulk in popliteal area. • Foot placement in descent – toes over edge to allow foot to roll over.

37. 2. Large power bursts are required in the stance hip & knee, and in a greater range than level walking. • Train through required ranges concentric & eccentric. • Vary tread depth & riser height to alter intensity. • “Power”, not strength. Consider speed & timing, esp as hip & knee extend together in ascent. • Consider: • Part practice – part range -> full range. • Double support -> single support. • Practice step to same level -> 2 steps. • Minimise use of hand for pulling up or weight bearing. • Maximal extension in ascent occurs before contralateral foot placement.

38. 3. In ascent, 2nd peak in GRF occurs at end of stance (vertical thrust), produced by PF’s. • No PF’s on amputated side – increased demand on extensors on intact side. • Older / frail vascular amputees may have difficulty ascending on intact limb as contribution from contralateral PF’s is absent -> need to train bilaterally. • Older / frail vascular amputees have weakness of intact PF’s (Winter et al 1990) -> increased demand on amputated side quads when ascending step over step.

39. 4. Hip & Knee flexion occur simultaneously during swing in ascent. • Train as a unit. • Make use of motion-dependent characteristics of swing (momentum/inertia) to assist. • Specific strategies to increase strength & recruitment of psoas & hamstrings. • How much circumduction is allowed?

40. 5. Activity in RF, VL, Gmax & Gmed is evident before foot contact. • Specificity of practice includes stages prior to targeted component to allow learning of preparatory actions.

41. 6. At no time is there a vertical shift of CoM without a concurrent horizontal shift. • Clients must be trained to move forward & up, or forward & down. • Consider what muscles / prosthetic components should be involved in assisting or limiting this movement. • Eg plantarflexors normally control forward movement during FCN in descent. • What has to compensate? • Will the client avoid forward movement as they feel they have no control?

42. 7. During descent, the largest GRF occurs at weight acceptance – 120%BW – and most energy is usually absorbed by PF’s. • Implications even in “bad leg to hell” patterns. • Landing is more stressful than lowering. • Eccentric control of quads/hip extensors/abductors must be trained during landing, including proper forward shift during WA, to assist in shock absorption and control forward shift in place of PF’s. • Increased demand on contralateral limb during it’s CL phase.

43. 8. No toe-strike during descent on prosthetic side. • Contralateral limb may have greater demands on • Knee joint flexion • Eccentric quads strength through that increased range. • Ankle dorsiflexion range. • Energy absorption through eccentric quads control -> train “impact” / knee flexion (no greater than ~230)

44. 9. Differences in kinematics & kinetics observed with Floor <-> step vs step <-> step. • Also need to include approach – planning step lengths appropriately, & different ranges / powers on different steps. • Training on 1 step does not always carry over to a flight of steps.

45. 10. Incorrect use of handrail is the most common compensation. • Pulling or weight bearing on rail masks kinematic or kinetic deviations. • Structure environment to minimise hand use but maintain safety: • Which side holds rail? Suggest ipsilateral. • Grip • Rail vs aid vs standby assist • Height of rail (or other hand support) • Step heights in part practice to allow practice of correct activation patterns. • Use of rail in normal fashion did not influence flexion / extension moments.

46. 11. Improve power in muscles that compensate for loss of ankle mechanism. • Ipsilateral VL, RF, (conc & ecc), hams as hip extensor • Contralateral PF’s, VL, RF, hams as hip extensor. • Ipsilateral hip flexors (no vertical thrust).

47. 12. Remember to train Core Stability for trunk control. • Increased “hip dominance”, but they will need a stable base to work off.

48. References Andriacchi, T.P, Andersson, G.B.J, Fermier, R.W, Stern, D, & Galante, J.O. (1980). A Study of Lower Limb Mechanics during Stair-Climbing. Journal of Bone and Joint Surgery, 62A, 5, 749-757. Livingston, L.A, Stevenson, J.M, & Olney, S.J. (1991). Stairclimbing kinematics on stairs of differing dimensions. Archives of Physical Medicine and Rehabilitation. 72, May, 398-402. Luepongsak, N, Amin, S, Krebs, D.E, McGibbon, C.A, & Felson, D. (2002). The contribution of type of daily activity to loading across the hip and knee joints in the elderly. Osteoarthritis and Cartilage. 10, 5, 353-359. Lyons, K., Perry, J, Gronley, J.K, Barnes, L, and Antonelli, D. (1983). Timing and relative intensity of hip extensor and abductor muscle action during level stair ambulation. Physical Therapy, 63, 10, 1597-1605. Masuda, K, Kim, J, Tanabe, K, & Kuno, S.Y. (2002). Determinants for stair climbing by elderly from muscle morphology. Perceptual and Motor Skills, Jun, 94, 3, Pt 1, 814-816. McFadyen, B.J, & Winter, D.A, (1988). An integrated biomechanical analysis of normal stair ascent and descent. Journal of Biomechanics. 21, 9, 733-744. Moffet, H, Richards, C.L, Malouin, F, & Bravo, G. (1993). Impact of knee extensor strength deficits on stair ascent performance in patients after medial meniscectomy. Scandinavian Journal of Rehabilitation Medicine. 25, 63-71. Powers, C.M, Boyd, L.A, Torburn, L, & Perry, J. (1997). Stair Ambulation in Persons with Transtibial Amputation: An Analysis of the Seattle Lightfoot. Journal of Rehabilitation research & Development, 34, 1, 9-18. Rowe, P.J, Myles, C.M, Walker, C, & Nutton, R. (2000). Knee joint kinematics in gait and other functional activities measured using flexible electrogoniometry: how much knee motion is sufficient for normal daily life? Gait and Posture, 12, 2, 143-155.

49. Torburn, L, Schweiger G.P, Perry, J. & Powers, C.M. (1994). Below-Knee Amputee Gait in Stair Ambulation: a Comparison of Stride Characteristics Using Five Different Prosthetic Feet. Clinical Orthopaedics & Related Research, 303, 185-192. Winter, D.A, Patla, A.E, Frank, J.S, & Walt, S.E. (1990). Biomechanical walking pattern changes in the fit and healthy elderly. Physical Therapy, 70, 6, 340-347. Yack, H.J, Nielson, D.H, & Shurr, D.G. (1999). Kinetic Patterns during Stair Ascent in Patients with Transtibial Amputations Using Three Different prostheses. Journal of Prosthetics & Orthotics, 11, 3, 57- Yu, B, Kienbacher, T, Growney, E.S, Johnson, M.E, & An, K.E. (1997). Reproducibility of the kinematics and kinetics of the lower extremity during normal stair climbing. Journal of Orthopaedic Research. 15, 3, 348-352. Zachazewski, J.E, Riley, P.O, & Krebs, D.E (1993). Biomechanical analysis of body mass transfer during stair ascent and descent of healthy subjects. Journal of Rehabilitation Research andDevelopment, 30, 4, 412-422.