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INTRODUCTION: The ability to move fingers independently is essential for skilled hand use and relies on both biomechanical constraints and neural control. This study analysed finger independence and associated brain activation during individuated finger movements using simultaneous recordings of 3D kinematics and functional MRI.

METHOD: Twenty-five right-handed persons (age 62.3 ± 8.2 years) performed flexion-extension movements with individual fingers repeated for each hand during fMRI acquisition. Finger independence was quantified using a 3D motion capture-based Individuation Index (II), and neural activity was analysed with whole-brain BOLD responses. Movement frequency was controlled for in the statistical models. Contrasts between individual fingers and the thumb were used to identify finger-specific brain control regions, followed by region-of-interest analyses of areas commonly activated by fingers with low II. Laterality indices assessed inter-finger differences in hemispheric activation patterns.

RESULTS: II were significantly higher for thumbs (0.98 ± 0.01) and index fingers (0.95 ± 0.03). The middle, ring, and little fingers showed comparable, lower II across both hands, with associations to increased activation in motor-related regions such as contralateral postcentral gyrus, ipsilateral cerebellum and ipsilateral central operculum. Laterality indices decreased with decreasing finger individuation, with significant reductions for the ring and little fingers compared to the index finger in parietal and postcentral regions.

CONCLUSION: The findings support that lower finger individuation ability is associated with increased recruitment of bilateral sensorimotor and ipsilateral cerebellar regions, even though the underlying mechanisms remain unclear. The integration of kinematic recordings in motor fMRI paradigms may be particularly useful for studying populations with impaired motor control, where variability in movement performance may otherwise confound interpretation of neural activation patterns.

Background: Physical exercise can help prolong healthy aging, yet few options enable older adults to exercise at very high intensities at home. A previous gym-based supramaximal High Intensity interval Training (HIT) protocol on stationary bicycles has shown promising results. Core components were supramaximal interval intensity that could be systematically modulated (controlled, individualized, escalated, and de-escalated) and protocol safety. In this exploratory co-creation study with older adults, we aimed to adapt the supramaximal HIT protocol for potential future implementation in older adults' home settings.

Methods: Eleven older adults (6 females; ages 69–74) with prior supramaximal HIT experience participated in this two-phase co-creation study. In phase one, co-creators engaged in workshops to identify, explore, and discuss available home-based training modalities. In phase two, co-creators took part in lab tests wherein suitable modalities were tested and compared to stationary bicycling regarding acute physiological responses and safety during a supramaximal HIT session (10 × 10-second intervals with 50-second passive recovery). Results were continuously merged with the protocol's core components.

Results: Physiological and emotional reactions to HIT, potential exercise modalities, and necessary protocol adaptations were identified in phase one. When merged with core components three modalities - walking up steps, chair stand, and rubber band cross country double poling - were selected for phase two testing. Of these, chair stand elicited physiological responses most comparable to stationary bicycling, while fulfilling all core components.

Conclusions: We adapted a researcher-supervised watt-controlled supramaximal HIT-protocol on stationary bicycles to a chair stand protocol with audio metronome-controlled intensity for potential implementation at home. This adaptation is the first step towards a safe and scalable implementation of a home-based supramaximal HIT program for older adults.

Objective: Given the clinical heterogeneity of Parkinson’s disease (PD), identification of early -stage subgroups with shared non-motor symptom (NMS) profiles may clarify its pathophysiology. This study used latent-profile analyses (LPA) to define subgroups based on sleep disturbances, cognitive performance and neuropsychiatric symptoms, and examined dopaminergic function and brain volume differences between them.

Methods: We analyzed data from 51 cognitively normal non-PD older adults and 105 early-stage PD participants from the iPARK trial, including 19 who underwent [11C]-raclopride PET/MR. Participants completed the Hospital Anxiety and Depression Scale, the short version of the Karolinska Sleep Questionnaire and a battery of neuropsychological tests. LPA were used in PD to identify subgroups based on NMS profiles, which were then characterized and examined in relation to dopaminergic integrity and brain morphology.

Results: LPA identified a two-cluster solution as the best fit. Group 1 (N = 49) showed poorer working memory, executive function and processing speed along with greater daytime sleepiness, depression and anxiety. Group 2 (N = 56) exhibited less affected cognitive function and minimal NMS. Groups were similar in demographics, disease duration, motor symptom severity and medication, but differed on UPDRS-1 NMS. Group 1 demonstrated significantly reduced [11C]-raclopride binding potential compared to Group 2 in the left putamen at both ROI- and voxel-wise analysis.

Conclusion: These findings indicate clinically distinct subgroups in early-stage PD. Greater NMS burden is linked to impaired dopaminergic integrity, suggesting a potential neurobiological signature. Early identification of such subgroups may improve understanding of disease heterogeneity and support personalized management and interventions. Clinical trial registration: https://clinicaltrials.gov/study/NCT03680170?id=NCT03680170&rank=1, identifier (NCT03680170).

Background: Normal brain aging is associated with dopamine decline, which has been linked to age-related cognitive decline. Factors underlying individual differences in dopamine integrity at older ages remain, however, unclear. Here we aimed at investigating: (i) whether inflammation is associated with levels and 5-year changes of in vivo dopamine D2-receptor (DRD2) availability, (ii) if DRD2-inflammation associations differ between men and women, and (iii) whether inflammation and cerebral small-vessel disease (white-matter lesions) serve as two independent predictors of DRD2 availability.

Methods: Analyses were performed in a sample of healthy adults > 60 years assessed at two measurement occasions separated by 5 years. At both occasions, DRD2 availability was estimated by ¹¹C-raclopride PET, and white-matter lesions by MRI. Inflammation was assessed by two C-reactive protein-associated DNA methylation scores at study baseline.

Results: Individuals with higher DNA methylation scores at baseline showed reduced striatal DRD2 availability. An interaction was found between DNA methylation scores and sex in relation to striatal DRD2 availability, such that associations were found in men but not in women. DNA methylation scores at study entrance were not significantly associated with 5-year striatal DRD2 decline rates. No significant association was found between DNA methylation scores and white-matter lesions, but higher scores as well as higher lesion burden were independently associated with reduced striatal DRD2 availability in men.

Conclusions: These findings suggest negative associations between one proxy of inflammation and DRD2 availability in older adults, selectively for men who had higher DNA methylation scores. Future studies should investigate other inflammatory markers in relation to dopamine integrity.

Background: Chaotic sporting environments require the performance of concurrent cognitive and motor tasks. A reduced capacity for either or both of the tasks when performed concurrently is known as cognitive-motor interference (CMi) and is believed to increase the injury risk. A greater susceptibility to CMi after a rupture of the anterior cruciate ligament (ACL) has been suggested to be caused by central nervous system adaptations, thus possibly contributing to high secondary ACL injury rates.

Purpose: To investigate whether patients after ACL reconstruction (ACLR) demonstrate greater CMi than noninjured controls when adding secondary cognitive tasks to the drop vertical jump (DVJ) and explore the potential influence of sex on CMi.

Study Design: Controlled laboratory study.

Methods: A total of 40 (50% male) sports-active patients who had undergone ACLR (mean, 24.9 ± 16.1 months after surgery) and 40 (50% male) sports-active noninjured controls performed DVJs with and without secondary cognitive tasks targeting short-term memory, attention, fast decision-making, and inhibitory control. Outcomes included a letter position recall task and 3 motor variables: (1) correct action (landing or landing with a subsequent vertical jump), (2) relative jump height (relative between DVJs), and (3) relative peak vertical ground-reaction force (relative between DVJs). Participants also completed isolated cognitive tests (CANTAB) included as covariates in multivariate analysis.

Results: Multivariate analysis of variance revealed that the ACLR group had greater CMi than the control group (P < .001), as manifested by more incorrect answers for the cognitive letter recall task (mean difference [MD], –13.3% [95% CI, –20.8% to –5.9%]; P < .001), more incorrect motor actions (MD, –7.5% [95% CI, −12.4% to –2.6%]; P = .003), and a reduced relative jump height (MD, –4.5% [95% CI, –7.9% to –1.2%]; P = .010). No difference in relative peak vertical ground-reaction force was found (MD, 2.8% [95% CI, –7.7% to 13.3%]; P = .59). Isolated cognitive outcomes did not affect these results, and there were no significant differences between male and female participants.

Conclusion: Patients after ACLR showed greater CMi than noninjured controls, which was unrelated to isolated cognitive outcomes, thus indicating aberrant neurocognitive function.

Clinical Relevance: Clinicians should consider cognitive and dual-task training and screening during ACL rehabilitation to better prepare patients for chaotic and uncontrolled sporting environments in which dual tasking is prevalent. Such interventions may help to reduce the risk of secondary ACL injuries.

Background: Physical activity and exercise are promoted worldwide as effective interventions for healthy ageing. Various exercise initiatives have been developed and evaluated for their efficacy and effectiveness among older populations. However, a deeper understanding of participants’ experiences with these initiatives is crucial to foster long-term activity and exercise among older persons.

Methods: A constructivist grounded theory study was conducted to explore the experiences of older persons participating in a supervised group supramaximal high-intensity training (HIT) programme. Four focus groups were held, involving 28 persons aged 65 to 78. The focus groups were analysed inductively, followed by an iterative process of abstraction, abduction, and theory generation using a constant comparative method. A conceptual framework comprising three theoretical concepts—stereotype embodiment, ageist practices, and self-efficacy—was employed during the abductive phase as an analytical lens.

Results: The core category of our grounded theory, Negotiating a physically active life in tune with ageing, encapsulates the complex processes and actions influencing older persons as they engage in physical activities in their daily lives and in relation to HIT. This core category was created from the conceptual framework and the four categories: Grit in the moment and overall life, Empowered by the training group, Navigating one’s physically active self, and Committing to exercise for duty and pleasure. Participants reported feeling invigorated by the exercise, enjoying the challenge, and valuing the group setup for its social connectedness and structure. The generated theory illustrates how participants’ engagement with physical activity and exercise is shaped by various perspectives accumulated over their lifespan. The findings provide a plausible explanation of how participation in HIT groups can challenge negative age stereotypes and ageist practices while enhancing self-efficacy for high-intensity exercise.

Conclusions: Our grounded theory underscores that physical activity and exercise should be regarded as multifaceted processes, which must be considered when promoting physical activity initiatives for older persons. By considering the older person and societal norms and values, we can gather knowledge to design physical exercise interventions that are not only effective but also enjoyable and capable of transforming how individuals perceive themselves as exercising persons.

Background: Supramaximal high-intensity interval training (HIT) programmes can be challenging to replicate outside research settings. This study aimed to explore its feasibility for older adults in a community setting, incorporating perspectives from exercise participants and instructors.

Methods: A pragmatic feasibility study using a convergent mixed- methods design involving four exercise instructors from one training facility and 21 older adult exercise participants (14 women, age-range 65–78). The previously used HIT programme consisted of 20-minute sessions that included a warm-up, ten 6-second intervals, and cool-down. Instructors first adapted the programme around these core components to their setting and then conducted 25 sessions. Both qualitative (individual interviews) and quantitative (estimated maximal oxygen consumption, estimated 6-second power, exercise- related motivation, and self-efficacy) data were collected and analysed (content analysis and descriptive statistics) in parallel. A taxonomy for implementation outcomes was used as an analytical matrix.

Results: Experiences of both participants and instructors revealed that the structure of the training was regarded as engaging, enjoyable, and supportive for establishing routines and promoting ownership of training progression. Participants found personalised and motivating approaches to engage with the programme and confidence in their abilities grew. Changes in exercise-related motivation and self-efficacy showed individual variation without a group trend. Participants who completed the intervention showed a positive median change in estimated 6-second power and maximal oxygen consumption, although individual responses varied. Experienced challenges included coordinating tasks during intervals and confidence in managing the programme. Barriers to fidelity and to scale-up were related to the practical complexity and fixed structure.

Conclusions: Supramaximal HIT can be implemented for older adults in a community setting with appropriate support, including individualised watt-based intensity and structured progression. The findings highlight how participants took ownership of their intensity progression, enabling them to challenge their limits. However, the fixed structure and complexity in managing short intervals may pose barriers to broader adoption. To enhance feasibility and scalability, simplifying interval management and providing clear, structured guidance are recommended. These insights help refine and optimize supramaximal HIT implementation for older adults in community settings.

Trial registration: Open Science Framework 31 January 2023 (https://doi.org/10.17605/OSF.IO/B7T2G).

Physical exercise shows positive effects on cognitive functions such as working memory (WM) for older adults; however, large individual differences in response exist and the underlying mechanisms are not well understood. We tested the hypothesis that exercise-induced changes in cardiorespiratory fitness and leg strength would improve WM-related brain activity, which subsequently would improve WM performance. This study was based on the Umeå HIT study, a randomized controlled trial assessing the effects of watt-controlled supramaximal high-intensity interval training (HIT) versus moderate-intensity training for nonexercising older adults (N=68). A subsample (n=43, 66 to 79 years, 56% females) underwent task-based functional magnetic resonance imaging, testing WM. The outcomes of interest were change in WM performance, WM task activation, cardiorespiratory fitness, and leg strength. For WM performance, we found no significant between-group difference in change; however, there was a significant within-group increase for HIT in WM composites. For HIT, changes in leg strength significantly predicted increased right dorsolateral prefrontal cortex activation, which in turn predicted improved in-scanner WM task performance. Cardiorespiratory fitness did not predict WM-related functional change. These results indicate a specific physiological ingredient, namely leg strength gains, that is a potential mechanism in exercise-induced prefrontal activation and WM performance increases.