Impact of an Exercise Programme on Single-Leg Drop Landing Stability and Lower Limb Alignment in Dancers with Flexible Pes Planus: An Exploratory Case Study / Ting-Yun Ku (2025)

Flexible pes planus (FPP) may compromise dancers’ lower limb alignment and postural stability, increasing the risk of injury during dynamic tasks such as single-leg landings. This case study investigated whether the four-week exercise programme, including proprioceptive neuromuscular facilitation (PNF) leg patterns and gluteus medius (GMed), targeting FPP-related instability and lower limb control, could improve frontal-plane knee alignment and postural stability during single-leg landing in dancers with FPP. Four female dancers with FPP (mean age 26.5 ± 3.5 years; dance experience 15 ± 5 years) conducted a four-week programme combining PNF leg patterns and GMed. Assessments at Pre-test (Week 0), Weeks 2–4, and post-test (Week 5) included time to stabilisation (TTS) and frontal-plane knee valgus angle (KVA) during single-leg drop landing. Navicular drop test (NDT) was conducted separately as a secondary outcome. Ground reaction forces were recorded using a force plate, and knee alignment was assessed using 2D video analysis. Data were analysed using individual time-series trajectories and group-level descriptive statistics. Group mean TTS improved by 22.8% (0.92 ± 0.36 s to 0.71 ± 0.13 s), and absolute knee deviation angles reduced by 42.0% (10.40 ± 5.84° to 6.03 ± 3.90°). NDT values decreased across all participants, with the greatest reduction of 8 mm observed in one case. Despite individual variability, overall trends suggested that a short-term combined PNF and GMed programme improved foot structure, dynamic landing stability, and frontal-plane knee alignment in dancers with FPP. These findings suggest a potential link between distal foot support and proximal joint control, supporting its potential to reduce malalignment and injury risk. Longer-term studies are warranted to evaluate sustained effects and generalisability. Key Points 1. 2. Integrating PNF leg patterns with GMed exercise improved single-leg landing stability and knee alignment in dancers with FPP. Potential positive changes were observed as early as Week 2, including TTS, knee 3 alignment and NDT values, suggesting short-term efficiency of the combined programme. 3. The low-equipment programme can be applied in dance training, warm-ups, or rehabilitation to enhance lower-limb stability and alignment.