Sprinting with bilateral transtibial running-specific prostheses versus biological limbs - are they comparable? Comments on Beck et al. (2022).

Since publication of this paper (Royal Society open science, 2022. 9(1): p. 211799), the authors have published a correction clarifying that the paper presents a case study that '… did not meet the definition for research with regard to human subjects'. The data are incorrectly referred to as experimental because the study has no experimental control. Furthermore, the paper has been presented previously but the version presented here selectively omits several analyses, posing a significant risk of bias. Of the prosthetic-related disadvantages identified by the authors, the most substantive was a 40% increase in time to 20 m (59.5 s.d. below the mean for NA sprinters). However the analysis was incomplete: acceleration modelling for NA sprinters continued up to 98% of maximum velocity, while Fastest BA was truncated at approximately 80%. We extrapolated the model, revealing the duration of maximum acceleration for Fastest BA is approximately 100% longer than NA sprinters. Important differences in Fastest BA contact lengths (0.10-0.15 m) were also identified. We posit that together, these large and important differences in sprint biomechanics and their likely physiological consequences suggest that running with and without prosthetics are so different that, although running times may be similar, the precautionary principle should apply and, in the interests of athletic competition integrity, runners with and without prosthetics should continue to compete separately.

The impact of strength level on adaptations to combined weightlifting, plyometric, and ballistic training.

The purpose of this investigation was to determine whether the magnitude of adaptation to integrated ballistic training is influenced by initial strength level. Such information is needed to inform resistance training guidelines for both higher- and lower-level athlete populations. To this end, two groups of distinctly different strength levels (stronger: one-repetition-maximum (1RM) squat = 2.01 ± 0.15 kg·BM-1 ; weaker: 1.20 ± 0.20 kg·BM-1 ) completed 10 weeks of resistance training incorporating weightlifting derivatives, plyometric actions, and ballistic exercises. Testing occurred at pre-, mid-, and post-training. Measures included variables derived from the incremental-load jump squat and the 1RM squat, alongside muscle activity (electromyography), and jump mechanics (force-time comparisons throughout the entire movement). The primary outcome variable was peak velocity derived from the unloaded jump squat. It was revealed that the stronger group displayed a greater (P = .05) change in peak velocity at mid-test (baseline: 2.65 ± 0.10 m/s, mid-test: 2.80 ± 0.17 m/s) but not post-test (2.85 ± 0.18 m/s) when compared to the weaker participants (baseline 2.43 ± 0.09, mid-test. 2.47 ± 0.11, post-test: 2.61 ± 0.10 m/s). Different changes occurred between groups in the force-velocity relationship (P = .001-.04) and jump mechanics (P ≤ .05), while only the stronger group displayed increases in muscle activation (P = .05). In conclusion, the magnitude of improvement in peak velocity was significantly influenced by pre-existing strength level in the early stage of training. Changes in the mechanisms underpinning performance were less distinct.

Assessing muscle strength for the purpose of classification in Paralympic sport: A review and recommendations.

OBJECTIVES: Classification in Paralympic Sport aims to minimize the impact of 10 eligible types of impairment on the outcome of competition. Methods for assessing the extent to which a given body structure or function has been impaired are required, but are challenging because it is not possible to directly measure an absence or loss. Rather, impairment must be inferred by measurement of extant body structures or functions. METHODS: This manuscript reviews the literature concerning the assessment of strength with the aim of identifying and describing the most appropriate method for inferring strength impairment in para-athletes. RESULTS: It is posited that the most appropriate voluntary strength assessment method for inferring strength loss in para-athletes will be multi-joint, isometric tests performed at joint angles that facilitate maximum force production. CONCLUSIONS: Evidence suggests such methods will permit development of tests that are specific to a variety of para-sports and which are reliable, ratio-scaled, and resistant to training. Future research should: develop sport-specific tests which are suitable for assessment of athletes with strength impairments of variable severity and distribution; and scientifically evaluate the extent to which such tests permit strength impairment to be validly inferred, including specific evaluation of the extent to which such measures respond to athletic training.

How much does lower body strength impact Paralympic running performance?

OBJECTIVES: Development of evidence-based methods of Paralympic classification requires research quantifying the relative strength of association between ratio-scaled measures of impairment and athletic performance. The purpose of this study was to quantify the extent to which muscle strength affects running performance in runners with and without brain impairment. DESIGN: Cross-sectional study. METHODS: Participants were 41 male runners: 13 with brain impairments (RBI) and 28 non-disabled (NDR). All participants completed a maximal 60-m sprint and a novel battery of three lower limb isometric strength tests. RESULTS: RBI showed significantly lower strength scores compared with NDR on the more affected side in leg flexion (176 vs. 243 N), leg extension (993 vs. 1661 N) and plantarflexion (824  vs. 1457 N). Significant differences were also seen on the less affected side in plantarflexion (1072 vs. 1508 N). RBI were significantly slower in the acceleration phase (0-15 m) (3.2 s ± 0.3 vs. 2.8 s ± 0.2) and top speed phase (30-60 m) (4.3 s ± 0.6 vs. 3.8 s ± 0.3). Correlation analysis showed stronger relationships between strength and running performance in RBI than NDR; however, the correlations were not significant. CONCLUSIONS: This study evaluated measures to assess strength for the purposes of classification and found that the measures were significantly different in RBI compared with NDR indicating the tests were able to capture strength impairment in this population. This study indicates that strength may be an important impairment type to assess in this population, as impairments of muscle strength may influence the outcome of running performance in athletes with more severe impairments.

Evaluation of methods for calculating maximum allowable standing height in amputees competing in Paralympic athletics.

The International Paralympic Committee has a maximum allowable standing height (MASH) rule that limits stature to a pre-trauma estimation. The MASH rule reduces the probability that bilateral lower limb amputees use disproportionately long prostheses in competition. Although there are several methods for estimating stature, the validity of these methods has not been compared. To identify the most appropriate method for the MASH rule, this study aimed to compare the criterion validity of estimations resulting from the current method, the Contini method, and four Canda methods (Canda-1, Canda-2, Canda-3, and Canda-4). Stature, ulna length, demispan, sitting height, thigh length, upper arm length, and forearm length measurements in 31 males and 30 females were used to calculate the respective estimation for each method. Results showed that Canda-1 (based on four anthropometric variables) produced the smallest error and best fitted the data in males and females. The current method was associated with the largest error of those tests because it increasingly overestimated height in people with smaller stature. The results suggest that the set of Canda equations provide a more valid MASH estimation in people with a range of upper limb and bilateral lower limb amputations compared with the current method.