Inter-segmental timing, quantified as foot-contact delay between body segments, emerged as a significant predictor of knee joint loading alongside established biomechanical predictors such as displacement velocity, body mass, and knee range of motion during stop-jump landings.
Key Findings
Results
Inter-segmental timing, quantified as foot-contact delay between body segments, was a significant predictor of knee joint loading across landing conditions.
Thirty-three male volleyball and basketball players performed stop-jump tasks.
Statistical Parametric Mapping and Linear Mixed Models were used to identify phase-specific differences and predictors of knee loading.
Inter-segmental timing emerged as 'an additional factor influencing knee joint loading alongside established biomechanical predictors such as displacement velocity, body mass, and knee range of motion.'
The finding extended previous work by highlighting the temporal coordination between body segments as a biomechanically relevant variable.
Results
Horizontal landing phases showed a stiffer biomechanical strategy compared to vertical landing phases.
Horizontal phases demonstrated reduced joint range of motion of 40–83% compared to vertical phases.
Horizontal landings were associated with increased knee valgus relative to vertical landings.
The stiffer strategy in horizontal landings was associated with higher anterior tibial shear forces (121% greater) and higher patellar tendon forces (156% greater).
Lower-limb kinematics, kinetics, patellar tendon forces, and anterior tibial shear forces were all calculated during the tasks.
Results
Anterior tibial shear forces were substantially higher during horizontal landing phases than vertical landing phases.
Anterior tibial shear forces during horizontal landing phases were 121% higher than during vertical landing phases.
These differences were associated with the stiffer landing strategy observed in horizontal phases.
The study used a stop-jump task to simulate sport-specific landing scenarios relevant to volleyball and basketball players.
Results
Patellar tendon forces were substantially higher during horizontal landing phases than vertical landing phases.
Patellar tendon forces during horizontal landing phases were 156% higher than during vertical landing phases.
Increased patellar tendon loading was associated with reduced joint range of motion and stiffer landing mechanics in horizontal phases.
Patellar tendon forces were directly calculated as part of the biomechanical analysis.
Results
Established biomechanical predictors of knee joint loading included displacement velocity, body mass, and knee range of motion.
These predictors were identified alongside inter-segmental timing using Linear Mixed Models.
The study confirmed previously established predictors while adding inter-segmental timing as a new contributing factor.
Statistical Parametric Mapping was used in combination with Linear Mixed Models to identify both phase-specific differences and predictors.
Discussion
The biomechanical differences between horizontal and vertical landing phases may be particularly relevant in unplanned sport landings altered by external perturbations.
The authors note that results 'may be particularly relevant in sport situations where landings are not fully planned and can be altered by external perturbations such as opponents' deceiving actions.'
The study population consisted of male volleyball and basketball players, sports in which deceptive opponent actions are common.
Horizontal landings, which produced greater knee loading, may more closely resemble unplanned or reactive landing scenarios in competition.
What This Means
This research suggests that the timing of how different body segments make contact with the ground during landing — called inter-segmental timing — plays a meaningful role in how much stress is placed on the knee. The study had 33 male volleyball and basketball players perform stop-jump tasks, which involve running, stopping, and jumping, and measured forces at the knee including those on the patellar tendon (the tendon connecting the kneecap to the shinbone) and the anterior tibial shear force (a forward-directed force on the shin that stresses the ACL). The researchers found that when segments of the body land in a poorly coordinated sequence, knee loading increases, adding a new timing-based factor to the already known predictors like body weight, movement speed, and knee bending range.
The study also found that horizontal landings — where an athlete is moving forward and stopping — produced dramatically higher knee forces than vertical landings, with patellar tendon forces 156% higher and anterior tibial shear forces 121% higher. Horizontal landings also showed stiffer movement patterns, less knee bending, and more knee collapse inward (valgus), all of which are associated with higher injury risk. These differences are important because in real sports, many landings happen unexpectedly, such as when an opponent fakes a move and forces an athlete to land awkwardly.
This research suggests that training programs aimed at reducing knee injury risk might benefit from addressing not just how much athletes bend their knees when landing, but also the coordination and timing of how their body segments sequentially absorb impact. The findings are particularly relevant for sports like volleyball and basketball, where athletes frequently land after jumping in unpredictable directions under competitive pressure.
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Schwartz C, Paulus J, Croisier J, Delhauteur L, Dubois E, Kaux J. (2026). Inter-Segmental Timing as A Contributing Factor to Knee Loading in Stop-Jump Landings.. Journal of sports science & medicine. https://doi.org/10.52082/jssm.2026.753