en پا و مچ پا Foot and Ankle مروری Review Paper <div style="text-align: justify;"><strong>Background</strong>: Obesity alters lower-extremity mechanics, increasing the risk of joint degeneration. While steady-state gait is well-documented, everyday transitional tasks are biomechanically demanding and under-synthesized in adults with obesity.&nbsp;<br> Objectives: This systematic review aimed to evaluate lower-extremity kinematics, kinetics, and postural stability during non-steady-state movements in this population.&nbsp;<br> <strong>Methods</strong>: Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) and synthesis without meta-analysis guidelines (International Prospective Register of Systematic Reviews [PROSPERO]: CRD420261473990), PubMed, Scopus, and Web of Science were systematically searched up to June 2026. Eligible studies assessed biomechanical outcomes during sit-to-stand (STS) transfers, stair negotiation, gait initiation (GI), and obstacle crossing in overweight or obese adults compared to normal-weight (NW) controls. Methodological quality was evaluated using the modified Downs and Black checklist.&nbsp;<br> <strong>Results</strong>: Thirty-eight studies comprising 1,366 participants were included. During STS transfers, individuals with obesity exhibited restricted trunk flexion, which doubled absolute peak knee extension moments compared to controls (e.g. 0.74 vs 0.31 Nm/kg, P<0.05). GI and obstacle navigation revealed significant lateral postural vulnerability, characterized by wider mediolateral center-of-pressure excursions (P=0.008) and reduced anteroposterior stability (P=0.008), which significantly deteriorated under cognitive dual-tasking (P=0.001). During stair negotiation and high-impact locomotion, body-mass-normalized joint moments were frequently comparable to NW peers; however, absolute non-normalized forces were severely elevated (e.g. absolute knee extension moments reaching 145 Nm during ascent, P<0.001). To compensate, a &ldquo;straighter knee&rdquo; strategy was frequently adopted in early stance (P<0.05). Furthermore, disproportionate peak pressures under the midfoot (up to a 7.7-fold increase, P<0.01) indicated dynamic arch collapse.&nbsp;<br> <strong>Conclusion</strong>: Obesity necessitates fundamental neuromotor reorganization during transitional tasks. While compensatory strategies preserve immediate dynamic balance, they inadvertently concentrate destructive absolute mechanical overload on the distal joints, elevating the risk of osteoarthritis. Effective management requires multidisciplinary approaches combining weight reduction, targeted exercise, and biomechanical interventions.</div> Biomechanics, Obesity, Osteoarthritis, Postural balance, Transitional movements 71 86 http://jros.iums.ac.ir/browse.php?a_code=A-10-2753-1&slc_lang=en&sid=1 Fariborz Imani fariborzimani@uma.ac.ir 10031947532846009294 0009-0002-5765-1771 No Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran AmirAli Jafarnezhadgero amiralijafarnezhad@gmail.com 10031947532846009295 10031947532846009295 Yes Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran Mahrokh Dehghani m.dehghani@uma.ac.ir 10031947532846009296 10031947532846009296 No Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran Elaheh Azadian azadian1@yahoo.com 10031947532846009297 10031947532846009297 No Department of Motor Behavior, Ha.C., Islamic Azad University, Hamedan, Iran. Ahmad Yazadnifar my.ahmadyazdani@gmail.com 10031947532846009298 0009-0005-2146-6074 No Department of Sports Biomechanics, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran