Inclusion Criteria:

• - Residing in the United States (residing in Alabama is not required) - English as primary language.

• - Between 18+ years old.

• - Diagnosis of MS.

• - Relapse free in the past 30 days.

• - Internet and email access.

• - Currently physically inactive (GLTEQ) - Able to ambulate without assistance (self-report and PDDS) - Willingness to complete the questionnaires.

• - Willingness to wear the accelerometer.

• - Willingness to undergo random assignment (BIPAMS or WellMS)

  Exclusion Criteria:

  - Individuals not meeting above inclusion criteria.

- Individuals with moderate to high risk for contraindications of possible injury or death when undertaking strenuous or maximal exercise (PARQ)

Cognitive impairment is prevalent, disabling, and poorly-managed among the 1 million Americans living with multiple sclerosis (MS). Indeed, 67% of adults with MS have cognitive impairment, particularly slowed cognitive processing speed (CPS), and this is associated with impaired learning and memory and worse fatigue, depression, anxiety, pain, and quality of life (QOL). This underscores the importance of identifying efficacious approaches for managing CPS impairment and its consequences among those with MS. There is merit in a remotely-delivered physical activity (PA) intervention for managing MS-related CPS dysfunction in MS. We have provided evidence from a pilot, randomized controlled trial (RCT) that an Internet-delivered PA intervention resulted in a clinically meaningful improvement in CPS among those with mild MS-related ambulatory disability; there were additional improvements in fatigue, depression, anxiety, pain, and QOL. The pilot RCT did not a priori recruit persons with MS who had objective CPS impairment nor examine sustainability of CPS changes over time, and it involved a waitlist control that did not account for the effects of attention and social contact. We leverage our experiences and preliminary results, and propose an appropriately-powered, Phase-II, RCT of a highly-developed and refined Internet-delivered PA intervention focusing on walking during ambulatory activities of daily living (steps/day) for yielding immediate and sustained improvements in remotely-assessed CPS among persons with mild MS-related ambulatory disability who demonstrate impaired CPS. The proposed study, if successful, will provide Class I evidence regarding the efficacy of a 6-month, Internet-delivered, PA intervention compared with an active control condition for improving important outcomes in 300 adults with MS who present with both mild MS ambulatory disability and impaired CPS. The primary outcome is the remotely-delivered Symbol Digit Modalities Test as a measure of CPS; the secondary outcomes include a remotely-delivered, objective measure of learning and memory and self-reports of fatigue, depression, anxiety, pain, and QOL; the tertiary outcome is accelerometry as an objective, device-based measure of PA. The conditions will be delivered by persons who are uninvolved in screening, recruitment, random assignment, and outcome assessment. We will collect outcomes on 3 occasions over a 12-month period (i.e., pre-intervention, immediately post-intervention, and 6-month follow-up). The outcomes will be collected using a blinded assessor. Data analyses will involve intent-to-treat principles, and mixed-effects models and logistic regression. The proposed research may yield "real-world" guidelines for free-living PA change that can be implemented for the treatment of CPS impairment in MS. Such an opportunity for rehabilitation of cognitive function using an approach with broad reach and scalability is paramount considering the prevalent, disabling, and poorly-managed nature of CPS impairment in MS and limited resources for its treatment.

Arms

Experimental: Behavioral Intervention for Physical Activity in MS (BIPAMS)

The current behavioral intervention consists of two primary components; an internet website and oneonone video chats with a behavioral coach.The internet website involves content delivered through interactive video courses.The interactive video courses are based on elements of social cognitive theory.Each course consists of an introduction,the primary content,and a take home message.The interactive courses include embedded,supplementary options such as videos on content and worksheets related to the topic.A pedometer is provided for tracking steps,and these steps will be entered into the website so progress can be monitored.The chats support adherence to the intervention,discussion of website material,supportive accountability,and reporting of adverse events/injuries.The chats are conducted facetoface through an online videoconferencing platform.The chats occur 7 times during the first 2 months,4 times during the second 2 months,and twice during the final 2 months of the intervention.

Sham Comparator: Wellness for MS (WellMS)

Provides an internet website and oneonone video chats that discuss materials about self-managing multiple sclerosis (MS) consequences and health indicators through methods other than physical activity.The materials are transformations of brochures provided by the National MS Society,including Gait or Walking Problems:The Basic Facts;MS and Your Emotions;Pain:The Basic Facts; Solving Cognitive Problems;Taming Stress in MS;Food for Thought:MS and Nutrition;and Vitamins,Minerals,and Herbs:An Introduction.The delivery of the internet materials and chat sessions will occur on the same time schedule and frequency as the intervention condition,and will have a comparable time commitment. The control condition will not involve tracking steps and a pedometer with not be provided.

Interventions

Behavioral: - Behavioral Intervention for Physical Activity in MS (BIPAMS)

A behavioral intervention that involves an internet website and one-on-one video coaching calls for increasing physical activity in people with MS.

Behavioral: - Wellness for MS (WellMS)

A behavioral intervention that involves an internet website and one-on-one video coaching calls for increasing wellness in people with MS.