DSpace Collection:

Effects of Acute Altitude, Speed and Surface on Biomechanical Loading in Distance Running

2026-01-01T00:00:00Z

Title: Effects of Acute Altitude, Speed and Surface on Biomechanical Loading in Distance Running Author(s): Ueberschär, Olaf; Riedl, Marlene; Fleckenstein, Daniel; Falz, Roberto Abstract: Altitude training camps are a popular measure to enhance endurance performance at sea level. This study elucidates the effects of acute altitude-induced hypoxia, running speed and surface on cadence, peak tibial acceleration (PTA), gait asymmetry and residual shock in distance running. Ten healthy, trained native lowlanders (6 males, 4 females; 28.2 ± 9.2 years; mean 𝑉˙O2,peak of 54.9 ± 5.9 mL min−1 kg−1) participated in this study. They ran 1500 m bouts of at 50, 1000 and 2300 m above mean sea level on paved roads and natural trails at three different speeds. Those speeds were chosen to represent the most common training zones and were defined as 𝑣1=90%⋅𝑣VT1, 𝑣2=12(𝑣VT1+𝑣VT2) and 𝑣3=100%⋅𝑣VT2, with 𝑣VT1 and 𝑣VT2 denoting the speeds at the ventilatory thresholds 1 and 2. Based on the experimental results, cadence increased by +2.2 spm per +1 km h−1 (p < 0.001) and fell by −1.1. spm per +1000 m of elevation (p < 0.001), whereas surface did not show any significant effect. Likewise, PTA was not affected by surface, but grew by 0.9 g per +1 km h−1 (p < 0.001), and decreased by −0.6 g per +1000 m in elevation, with significant effects particularly at speeds beyond vVT1 (p < 0.049). Absolute lateral asymmetry was not altered by elevation, surface or running speed. Mean shock attenuation increased with running speed by +2.5 percentage points per +1 km h−1 (p < 0.001) but was independent of elevation and surface. In essence, running speed seems to be the predominant factor defining biomechanical loading, even under acute hypoxia and for varying surface conditions.

Limited Short-Term Reliability of Key Joint Angles in Biomechanical Running Gait Analyses

2025-12-22T00:00:00Z

Title: Limited Short-Term Reliability of Key Joint Angles in Biomechanical Running Gait Analyses Author(s): Ueberschär, Olaf; Pökel, Christoph; Bartsch, Julia; Schödel, Cindy Abstract: Background: Video-based biomechanical running gait analysis is widely used to optimise technique, guide footwear selection, and identify orthopaedic risk factors. Despite the increasing availability of such assessments, it is often assumed—without strong empirical support—that key kinematic parameters of running gait remain stable over short periods of time. This study aimed to examine the short-term stability of key joint angles during running using a standard 2D video-based kinematic analysis. Specifically, it was investigated whether these angles change within the first 4 min of treadmill running under three defined conditions: barefoot at 12 km h−1, shoed at 12 km h−1, and shoed at 14 km h−1, in a homogeneous sample of twelve young, trained, male recreational soccer players. Methods: Participants completed three four-minute runs. Joint angles were quantified manually from 2D video recordings. Temporal variation was analysed using repeated-measures statistics, intraclass correlation coefficients (ICCs), and minimal detectable changes (MDCs). Results: Six out of nine joint angles showed statistically significant temporal changes, mainly in hip extension, knee flexion, the Duchenne angle, the Trendelenburg angle, the leg axis angle, and heel-bottom angle. Lower leg angle and Achilles tendon angle remained stable. ICCs showed moderate to excellent agreement, indicating high within-session consistency across all angles. Discussion: Under the applied study protocol, significant short-term variations were observable in several joint angles during the first four minutes of running. These findings highlight the importance of analysing multiple strides and considering measurement uncertainty when interpreting short-duration running kinematics.

Runners with lower dynamic stability exhibit better running economy

2025-10-31T00:00:00Z

Title: Runners with lower dynamic stability exhibit better running economy Author(s): Diecken, Carlo; Riedl, Marlene; Willwacher, Steffen; Ueberschär, Olaf Abstract: Maintaining dynamic stability during running incurs an energetic cost that does not contribute to forward propulsion. Despite this, dynamic stability has received little attention as a potential factor influencing running economy. To understand the relationship between dynamic stability and running economy, nineteen trained runners were tested on a treadmill across three individualized speeds. Whole-body dynamic stability was quantified via a single maximum Lyapunov exponent (MLE) computed from a 21D state-space embedding, which incorporated 3D angular velocities from seven body segments (bilateral: shank, upper torso, forearm; unilateral: lower torso) and running economy was measured as cost of transport (COT) using metabolic gas-exchange data. Linear mixed-effects models were used to assess the relationship between MLE and COT as well as the effects of running speed on MLE. MLE was negatively associated with COT (p = 0.049), while running speed had no significant effect on MLE (p > 0.579). This study is the first to demonstrate that the MLE calculated from a multivariate state-space is negatively associated with COT, indicating that runners with lower dynamic stability exhibit better running economy. Further, MLE was not affected by running speed, indicating that this measure of whole-body dynamic stability can be robustly assessed at a range of running speeds. These results may hint at a previously unexplored avenue to improve running economy through alteration of dynamic stability characteristics.

Association between continuous device-based physical activity monitoring over six months and cardiorespiratory, metabolic and body composition outcomes in post-surgery cancer survivors : An observational cohort analysis within a randomized controlled trial (CRBP-TS Study)

2025-08-09T00:00:00Z

Title: Association between continuous device-based physical activity monitoring over six months and cardiorespiratory, metabolic and body composition outcomes in post-surgery cancer survivors : An observational cohort analysis within a randomized controlled trial (CRBP-TS Study) Author(s): Falz, Roberto; Leps, Christian; Bischoff, Christian; Gockel, Ines; Tegtbur, Uwe; Kwast, Stefan; Pökel, Christoph; Voß, Johannes; Rinser, Hans-Jürgen; Busse, Martin Abstract: The current guidelines for physical activity often rely on self-reported data or short-term activity tracking. We aimed to explore device-based long-term physical activity tracking and its possible association with cancer survivors’ cardiorespiratory fitness (CRF), metabolic health, and body composition.