Cadence in youth long-distance runners is predicted by leg length and running speed

Risk Factors for Rapid Cognitive Decline in Amyloid-Negative Individuals Without Cognitive Impairment or With Early-Stage Cognitive Loss in Screening Tests

PURPOSE

Although rapid cognitive decline (RCD) is an important unfavorable prognostic factor, not much is known about it, especially in amyloid-negative individuals. The purpose of this study was to investigate risk factors for RCD in amyloid-negative individuals.

PATIENTS AND METHODS

We retrospectively enrolled 741 individuals who were either cognitively unimpaired or had early-stage cognitive ability loss and who underwent 18F-florbetaben (FBB) (n = 402) or 18F-flutemetamol (FMM) (n = 339) PET/CT. Based on visual and semiquantitative (SUV ratio [SUVR]-based) analysis, the following amyloid-negative groups were established: visual-negative FBB (n = 232), visual-negative FMM (n = 161), SUVR-negative FBB (n = 104), and SUVR-negative FMM (n = 101). Univariable and multivariable logistic regression analyses were performed for RCD using 5 SUVRs, 5 cortical thicknesses, and 5 neuropsychological domains and clinico-demographic factors.

RESULTS

In the amyloid-negative groups, a decline in language function was commonly identified as a significant risk factor for RCD (P = 0.0044 in the visual-negative FBB group, P = 0.0487 in the visual-negative FMM group, P = 0.0031 in the SUVR-negative FBB group, and P = 0.0030 in the SUVR-negative FMM group). In addition, declines in frontal/executive function, frontal SUVR, and parietal SUVR; a longer duration of education; and mild cognitive decline in the amyloid-negative groups were also significant risk factors for RCD.

CONCLUSIONS

Even in amyloid-negative individuals without cognitive impairment or with early-stage cognitive ability loss, those with decreased language and frontal/executive functions on neuropsychological testing are at risk of progression to RCD.

Effect of applied cadence in repeated sprint cycling on muscle characteristics

PURPOSE

This study aimed to investigate physiological responses, muscle-tendon unit properties of the quadriceps muscle, and mechanical performance after repeated sprint cycling at optimal and 70% of optimal cadence.

METHODS

Twenty recreational cyclists performed as first sprint performance cycling test and during subsequent sessions two repeated sprint cycling protocols at optimal and 70% of optimal cadence, in random order. The muscle-tendon unit outcome measures on the dominant leg included muscle thickness, fascicle length (Lf), pennation angle (θp), and stiffness for the rectus femoris (RF), vastus lateralis (VL), and vastus medialis muscle (VM) at baseline, immediately after repeated sprint cycling, and 1-h post-exercise.

RESULTS

The results showed an increase in muscle thickness and θp in RF, VL, and VM for both cadences from baseline to immediately after exercise. The Lf decreased in RF (both cadences), while stiffness decreased in RF, VL, and VM at optimal cadence, and in VL at 70% of optimal cadence from baseline to immediately after exercise.

CONCLUSION

The present study revealed that the alterations in muscle characteristics were more marked after repeated sprint cycling at optimal cadence compared with a lower cadence most likely as a result of higher load on the muscle-tendon unit at optimal cadence.

Race and geography impact validity of maximum allowable standing height equations for para-athletes

World Athletics use maximum allowable standing height (MASH) equations for para-athletes with bilateral lower extremity amputations to estimate stature and limit prosthesis length since longer prostheses can provide running performance advantages. The equations were developed using a white Spanish population; however, validation for other races and geographical groups is limited. This study aimed to determine the validity of the MASH equations for Black and white Americans and whether bias errors between calculated and measured stature were similar between these populations. Sitting height, thigh length, upper arm length, forearm length, and arm span of 1899 male and 1127 female Black and white Americans from the Anthropometric Survey of US Army Personnel database were input into the 6 sex-specific MASH equations to enable comparisons of calculated and measured statures within and between Black and white groups. Two of 12 MASH equations validly calculated stature for Black Americans and 3 of 12 equations were valid for white Americans. Bias errors indicated greater underestimation or lesser overestimation of calculated statures in 10 equations for Black compared to white Americans and in 2 equations for white compared to Black Americans. This study illustrates that race and geography impact the validity of MASH equations.