Lower-Body Aquatic Training Prescription for Athletes

Video-driven simulation of lower limb mechanical loading during aquatic exercises

Understanding the mechanical demands of an exercise on the musculoskeletal system is crucial to prescribe effective training or therapeutic interventions. Yet, that knowledge is currently limited in water, mostly because of the difficulty in evaluating external resistance. Here I reconcile recent advances in 3D markerless pose and mesh estimation, biomechanical simulations, and hydrodynamic modeling, to predict lower limb mechanical loading during aquatic exercises. Simulations are driven exclusively from a single video. Fluid forces were estimated within 12.5±4.1% of the peak forces determined through computational fluid dynamics analyses, at a speed three orders of magnitude greater. In silico hip and knee resultant joint forces agreed reasonably well with in vivo instrumented implant recordings (R²=0.74) downloaded from the OrthoLoad database, both in magnitude (RMSE =251±125 N) and direction (cosine similarity = 0.92±0.09). Hip flexors, glutes, adductors, and hamstrings were the main contributors to hip joint compressive forces (40.4±12.7%, 25.6±9.7%, 14.2±4.8%, 13.0±8.2%, respectively), while knee compressive forces were mostly produced by the gastrocnemius (39.1±15.9%) and vasti (29.4±13.7%). Unlike dry-land locomotion, non-hip- and non-knee-spanning muscles provided little to no offloading effect via dynamic coupling. This noninvasive method has the potential to standardize the reporting of exercise intensity, inform the design of rehabilitation protocols and improve their reproducibility.

Effects of Aquatic Training and Bicycling Training on Leg Function and Range of Motion in Amateur Athletes with Meniscal Allograft Transplantation during Intermediate-Stage Rehabilitation

Meniscal allograft transplantation (MAT) is a treatment modality for restoring knee function in patients with irreversible meniscal injury. Strengthening programs to promote functional recovery are treated with caution during the intermediate rehabilitation phase following MAT. This study analyzed the effects of aquatic training (AQT) and bicycling training (BCT) during the intermediate stage of rehabilitation in amateur athletes that underwent MAT. Participants (n = 60) were divided into AQT (n = 30) and BCT (n = 30) groups. Both groups performed training three times per week from 6 to 24 weeks following surgery. International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) score, knee joint range of motion (ROM), isokinetic knee strength, and Y-balance test (YBT) performance were evaluated. All measured variables for the AQT and BCT groups improved significantly after training compared with pre-training values. The IKDC score and YBT were significantly higher for AQT than for BCT. The knee flexion ROM and isokinetic muscle strength were significantly improved in the BCT group compared to those in the AQT group. The AQT group exhibited greater improvement in dynamic balance, whereas BCT provided greater improvement in isokinetic muscle strength. AQT and BCT were effective in reducing discomfort and improving knee symptoms and functions during intermediate-stage rehabilitation following MAT in amateur athletes.

Effects of High-Intensity Aquatic or Bicycling Training in Athletes with Unilateral Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFPS) is one of the most common overuse injuries experienced by athletes. It is characterized by pain and functional deficits that lead to decreased performance, thereby limiting sports activity. Therefore, optimal training interventions are required to improve physical fitness and function while minimizing pain due to PFPS. This study aimed to compare and analyze the effects of high-intensity aquatic training (AT) and bicycling training (BT) in male athletes with PFPS. Fifty-four athletes with PFPS were divided into AT and BT intervention groups. Intervention training was conducted three times per week for 8 weeks. Cardiorespiratory fitness was evaluated using the graded exercise test (GXT) based on peak oxygen uptake (VO₂ peak), and anaerobic threshold. For the knee strength test, extension and flexion were performed and measured using isokinetic equipment. One-leg hop tests and the Y-balance test (YBT) were performed to evaluate dynamic balance, and the International Knee Documentation Committee (IKDC) scoring system was used for subjective knee evaluation. The GXT, YBT, and IKDC scores were reported according to the group and duration of the intervention. After training, VO₂ peak, YBT, knee extension strength, and IKDC score improved significantly in both the AT and BT groups compared with the pre-training values. Furthermore, the AT group exhibited significant improvement compared with the BT group. We demonstrated that AT and BT effectively improved the symptoms and muscle strength of athletes with PFPS who were only able to engage in limited high-intensity field training. AT produced a modestly better effect than BT.