Juha-Pekka Kulmala
Ongoing research
Constraints on normal gait in Cerebral Palsy
Cerebral Palsy (CP) is the most common severe movement disorder limiting gait and functioning in children. Despite the presence of several treatment strategies, results are often disappointing; walking remains highly impaired and patients continue to rely on their compensatory gait strategies.
Through this project we aim to better undertand why patients adopt certain compensatory gait patterns. Spesifically, we will examine the relative efforts of the major lower limb muscle groups during locomotion. The goal is to establish a new clinical protocol for determining individual gait constraints in patients to enhance treatment planning in practice.
[link to the PlosONE study examining the effort equalization hypothesis]
Wearable robotics in gait rehabilitation
Recent achievements in rehabilitation robotics present a promising way to attain more normal walking behavior. Through this project we investigate the effects of a novel exosuit-based gait rehabilitation strategy on gait functionality, daily physical activity and participation in children with cerebral palsy. The ultimate goal is to develop better rehabilitation strategies for gait disorders.
[link to the pilot study examining how exosuit affects gait in children with CP]
Previous work in locomotor constraints
Although human locomotion has been extensively studied, it has been unclear which muscles actually constrain our walking and running performance. Such knowledge would be valuable not only for optimizing locomotor performance but also for preventing locomotor impairments.
Locomotor decline in older age
Although aging is known to lead a progressive decline in human locomotor performance, it has been unclear, however, which lower extremity muscles are mainly responsible for this deterioration?
Our study reveals that, regardless of mode of locomotion, age-related locomotor decline mainly depends on decreased calf muscle function.
[link to the study] [Runner's world]
Muscular efforts in locomotion
For the first time, we provided a reasonable approximation of the quadriceps and calf muscle
efforts for human level locomotion. We found that
across walking, running and sprinting, the calf muscles operate at a clearly greater proportion of their maximal capacity compared with the quadriceps muscle. This finding may explain why ankle push-off deficit plays a key role in age-related locomotor decline.
[link to the MSSE study] [ACSM Highlight]
Frontal plane mechanics in locomotion
From a balance control point of view, human bipedalism poses a major challenge to our locomotor system especially in the frontal plane.
Our study identified age-spesific differences in the hip and upper body mechanics providing new insight into dynamic balance control.
[link to the study] [Editor's Choice Sep 2017]
Previous work in lower extremity mechanics and loading
It is generally accepted that excessive loading plays a major role in the development of musculoskeletal injuries and disorders. To prevent these problems, it is essential to understand the underlying factors associated with excessive loading during locomotion.
Walking-induced knee loading
Previous studies have shown link between high knee loading and the development of knee osteoarthritis (OA). Therefore, understanding the exact mechanisms that result in higher than normal knee loading may help to prevent knee OA.
By comparing knee loading profiles among individuals with different gait patterns we found that those who exhibited either quadriceps or hamstring dominant gait patterns had significantly higher medial knee loading compared to subjects with a typical gait pattern. These findings suggest that walking pattern may play an important role in the development or progression of knee osteortritis.
Running-related loading and injuries
Running is a simple exercise form with great cardiovascular health benefits. However, at some point almost every runner faces a harmful side-effect - overuse injuries, which typically result from repeated loading of the musculoskeletal structures.
Importantly, it should be noted that running with a forefoot versus rearfoot striking technique causes a clearly different lower extremity loading profiles which may potentially cause different injuries.
[link to the study] [ACSM Highlight] [NY Times]
Shoe cushioning, leg stiffness and impact loads
Interestingly, shoes with maximalist cushion may not be able to protect againts running-related injuries. Our study shows that running in highly cushioned shoes increases leg stiffness and amplify rather than attenuate impact loading.
[link to the study] [New Scientist]