The biomechanics of one-footed vertical jump performance in unilateral trans-tibial amputees

Abstract

This study investigated vertical jumps from single support for two trans-tibial amputees from a standing position. The mechanisms used to achieve flight and the compensatory mechanisms used in the production of force in the absence of plantarflexors are detailed. Two participants completed countermovement maximum vertical jumps from the prosthetic and the sound limbs. The jumps were recorded by a 7-camera 512 VICON motion analysis system integrated with a Kistler forceplate. Flight height was 5 cm jumping from the prosthetic side and 18 -19 cm from the sound side. The countermovement was shallower and its duration was less on the prosthetic side compared to the sound side. The reduced and passive range of motion at the prosthesis resulted in an asymmetrical countermovement for both participants with the knee and ankle joints most affected. The duration of the push-off phase was not consistently affected. At take-off the joints on the sound side reached close to full extension while on the prosthetic side they remained more flexed. Joint extension velocity in the push-off phase was similar for both participants on the sound side, though the timing for participant 2 illustrated earlier peaks. The pattern of joint extension velocity was not a smooth proximal to distal sequence on the prosthetic side. The magnitude and timing of the inter-segment extensor moments were asymmetrical for both subjects. The power pattern was asymmetrical in both the countermovement and push-off phases; the lack of power generation at the ankle affected that produced at the remaining joints.

Asymmetrical loading demands associated with vertical jump landings in people with unilateral transtibial amputation

“…However, for the participants with TTA, asymmetries were generally substantial with relatively low F 2 magnitudes on the prosthetic side and F 2 magnitudes comparable with those of the ND participants on the intact side. While it is not possible to directly compare the F 2 magnitudes with the literature because of the substantially reduced heights from which the participants with TTA landed, we noted that the participants with TTA experienced similar F 2 magnitudes on the intact side compared with ND jumpers in literature performing drop landings from 0.30 m [9,[33][34], despite landing from heights of only 0.15 ± 0.06 m. These reduced FHs, compared with ND participants in literature [35][36], are consistent with a previous study using recreationally active people with amputation [19] and may be related to their reduced capacity to produce the required mechanisms to propel the body into flight [18].…”

“…The demands placed on the lower limbs when people with amputation perform dynamic movements with greater impact characteristics are unknown. Previous research has looked at amputation jump takeoff characteristics [17][18][19] but no research has looked at the landing phase of the jump. Research on unilateral TTA walking and running gait has reported asymmetry where the intact limb experiences a greater loading than the prosthetic limb and/or ND persons [20][21][22].…”

Motion-analysis studies of transtibial prosthesis users

“…Given that a large majority of papers required subjects to walk on level surfaces at self-selected velocities, which normally produces a frequency content under 10 Hz, 22 a frequency of 50 Hz is considered sufficient to ensure that the data accurately portrays the signal in the time domain without missing peak values. 23 The one paper which involved jumping 24 utilized a frequency capture of 120 Hz, which is likely to be sufficient given the accelerations required in this activity. The capture frequency of the system during data collection was not stated in 13 papers.…”

“…[25][26][27] Of particular methodological interest in the papers included in this review is the method of marker placement on the prosthetic limb. Of the 68 studies reviewed, 33 stated that the markers were positioned on the prosthesis by estimating the location of landmarks from the intact limb, 9,12,24, and 35 studies did not state how the positions of the markers were determined [1][2][3][4][5]8,10,11,[13][14][15][16]21,48, (Table 2). None of the studies specified use a technique involving measurement of the intact limb, although some of the biomechanical models used do require that measurements be inputted into the system.…”

“…106 Of note are differences that can be observed in the manner in which kinematic results related to the prosthetic foot were presented. Many articles investigating prosthetic feet state only the dorsiflexion angles 2,24,39,42,44,54,73 while others choose to state both plantarflexion and dorsiflexion. 1,35,69,71 Some articles list only the absolute range of motion (ROM) for specific feet.…”