Hochschule Trier

Backpacks are essential in the daily lives of children. Carrying a heavy backpack affects trunk posture during standing. It remains unclear, whether this effect is also observed during gait.

How do different backpack weights affect trunk kinematics during walking in children?

Sixteen children stood and walked on a 5 m walkway with a custom load-carrying-system simulating unloaded and loaded backpacks (10 %;20 %;30 % of body mass (BM). A marker-based 3D motion analysis system captured whole-body kinematics (Rizzoli model). During walking, the primary outcomes were the maximum ranges of motion (RoM;[°]) of thoracic and lumbar trunk segmental angles in three planes. During standing, the average angles over 5 s were measured in three planes. Secondary measures included stride length, stride time, and velocity during walking. The children's own backpacks' weights were measured and expressed as a percentage of body mass. Statistical analysis was performed using repeated-measures ANOVA (α=0.05) and Tukey-Kramer post hoc test.

The average weight of the children's own backpack was 15.4 ± 7.4 %BM. For the experimental conditions, the average weights added to the load-carrying system were 3.3 ± 0.8 kg (10 %BM), 6.5 ± 1.7 kg (20 %BM), and 9.8 ± 2.5 kg (30 %BM). During standing, the average trunk flexion angles (sagittal plane) of the lumbar trunk segment significantly increased with increased backpack weight (p = 0.002). During walking, no changes in sagittal plane RoM but significant decreases in lumbar and thoracic transversal and frontal plane RoM (p < 0.001), stride length (p = 0.047) and velocity (p = 0.041) were observed with additional weight. No significant differences were observed for stride time between the conditions.

Added backpack weight led to a more flexed trunk posture during standing and reduced transversal and frontal plane trunk movement, stride length, and gait velocity during walking. These adjustments likely compensate for the dorsally displaced center of mass and minimize energy expenditure by reducing trunk-backpack-angular momentum during walking.

Manual therapy (MT) is a widely utilized approach for managing musculoskeletal pain and functional disorders, particularly through joint mobilizations. Traditionally explained by immediate biomechanical processes, a paradigm shift has occurred in the last few decades, recognizing neurophysiological mechanisms as crucial contributors.

To evaluate whether this shift is also reflected by clinicians, this study explores the beliefs and perceptions of physical therapists regarding the mechanisms underlying MT through an online survey design. The focus was if dominantly peripheral biomechanical model or a neurophysiological explanatory model prevails.

The study involved a national cross-sectional survey of 569 physical therapists, average age 36.5y (9.7), and 58 % female. Based on a fictitious case scenario, participants rated on a scale from 0 % to 100 %, the involvement of anatomical structures and physiological mechanisms and provided additional suggestions.

The majority of responders attributed significant involvement to the brain (75 %), myofascial structures (71 %), peripheral nervous system (68 %), and cervical joints (60 %). Mechanisms such as endogenous pain modulation (73 %), placebo effects (72 %), muscle activity (68 %), and neuromuscular responses (62 %) were commonly endorsed. The data indicated that socio-demographic and work-related characteristics are weakly associated to specific beliefs, emphasizing the complex nature of these perspectives. The findings underscore the diversity in physical therapists' beliefs and highlight the importance of understanding the mechanisms, as they significantly contribute to the perceived effectiveness of MT.

This study provides valuable insights into the current landscape of beliefs among German physical therapists, contributing to the ongoing dialogue between basic research and clinical practice in MT.

In acute stroke patients, arithmetic fact retrieval deficits have been observed due to disrupted white matter connections within a left-hemispheric network centered around the angular gyrus and middle temporal gyrus (Smaczny et al., 2023). However, it remains unclear which specific structural disconnections also hinder successful remediation in the chronic stage of stroke. In this study, 92 patients were examined to determine which impairments continue to affect multiplication performance even in the chronic phase after a first-time unilateral left-hemispheric stroke. Our results revealed a strong association between impaired multiplication performance and the disconnection of left long-term memory (para)hippocampal areas from left frontal and right parietal regions. Thus, unlike previous findings in the acute stroke phase, our results in the chronic phase emphasize the importance of (para)hippocampal regions for successful multiplication performance. We suggest that the affected areas and connections in chronic patients with persistent multiplication problems not only indicate areas that are crucial for the relearning of arithmetic facts, but also those crucial for the learning of arithmetic facts in general. More generally, we suggest that the acquisition of arithmetic facts depends on structural integrity of a network centered around the left (para)hippocampus, while the retrieval of consolidated arithmetic facts from memory relies on the integrity of a left-hemispheric network involving angular gyrus and middle temporal gyrus.