Normative Spatiotemporal Parameters During 100-m Sprints in Amputee Sprinters Using Running-Specific Prostheses.

The aim of this study was to develop a normative sample of step frequency and step length during maximal sprinting in amputee sprinters. We analyzed elite-level 100-m races of 255 amputees and 93 able-bodied sprinters, both men and women, from publicly-available Internet broadcasts. For each sprinter's run, the average forward velocity, step frequency, and step length over the 100-m distance were analyzed by using the official record and number of steps in each race. The average forward velocity was greatest in able-bodied sprinters (10.04 ± 0.17 m/s), followed by bilateral transtibial (8.77 ± 0.27 m/s), unilateral transtibial (8.65 ± 0.30 m/s), and transfemoral amputee sprinters (7.65 ± 0.38 m/s) in men. Differences in velocity among 4 groups were associated with step length (able-bodied vs transtibial amputees) or both step frequency and step length (able-bodied vs transfemoral amputees). Although we also found that the velocity was greatest in able-bodied sprinters (9.10 ± 0.14 m/s), followed by unilateral transtibial (7.08 ± 0.26 m/s), bilateral transtibial (7.06 ± 0.48 m/s), and transfemoral amputee sprinters (5.92 ± 0.33 m/s) in women, the differences in the velocity among the groups were associated with both step frequency and step length. Current results suggest that spatiotemporal parameters during a 100-m race of amputee sprinters is varied by amputation levels and sex.

Age-independent and age-dependent sex differences in gait pattern determined by principal component analysis.

Although various studies have reported significant sex differences in pelvic and/or hip-joint motion during normal walking in healthy adults, it is still unclear whether such differences are among the most dominant age-independent sex differences. This study was conducted to analyze the whole waveform of lower-extremity joint kinematics obtained from 191 healthy adults using a principal component analysis (PCA). The PCA was conducted using a 955×1212 input matrix constructed from the participants' time-normalized pelvic and right-lower-limb-joint angles along three axes (five trials of 191 participants×101 data points×4 angles×3 axes). Two-way (age×sex) analyses of variance were conducted on the principal component scores (PCSs) of principal component vectors (PCVs) 1 through 6, each of which explained more than 5% of the variance. We identified a PCV that exhibits a significant age-sex interaction (PCV 1). The characteristics of sex differences reported in previous studies could be observed in the reconstructed waveforms of this PCV. Thus, we can conclude that the sex differences in the gaits reported in previous studies are not consistent across age groups. Furthermore, we also found a PCV that exhibited only a significant sex difference (PCV 6). This PCV was the first and only PCV to exhibit a sex difference without any age-related effect or age-sex interaction. Therefore, we concluded that the movement related to this PCV is age-independent and is the most dominant sex difference in the gaits observed during normal walking.

Does amputation side influence sprint performances in athletes using running-specific prostheses?

BACKGROUND: For athletes using running-specific prostheses (RSPs), current Paralympic guidelines for track events are generally based on level of amputation, not side of amputation. Although 200- and 400-m sprint races are performed in a counterclockwise direction, little is known about the effects of amputation side on race performance in athletes with unilateral lower limb amputation. The study aim was to test whether athletes using RSPs on their left side have slower race times than those using RSPs on their right side. FINDINGS: Athletes with unilateral lower limb amputation (N = 59 in total) participating in elite-level 200-m races were analyzed from publicly available Internet broadcasts. These races included the 2008 Beijing and 2012 London Paralympics, and the International Paralympic Committee Athletics World Championships in 2011 and 2013. For each athlete the official race time and amputation side were determined. There was no significant difference in number of participants and race time between left and right side amputees in T42 men, T44 men, and T44 women. CONCLUSION: The results of the present study suggest that sprint performance of athletes using RSPs is not affected by amputation side on a standard 400-m track.