Mental Effort During Low Load Resistance Training in Older Adults

The Effect of Maximal Mental Effort During Resistance Training on Physical Function and Motor Unit Behavior in Older Adults

The goal of this clinical trial is to determine the effect of maximal mental effort combined with low-intensity resistance training on strength and neuromuscular function in older adults. The main questions it aims to answer are:

• Does low-intensity resistance training in combination with maximal mental effort increase strength more than low intensity resistance training alone?
• Does low-intensity resistance training in combination with maximal mental effort improve neuromuscular function more than low intensity resistance training alone?

Participants will be randomly assigned to 1 of 3 groups:

• Low intensity resistance training
• Low intensity resistance training with maximal mental effort
• Control Researchers will compare groups to determine differences in changes in strength, neuromuscular function, and body composition.

Participants in both training groups will perform 8 weeks of low intensity, whole-body resistance training. Participants in the control group will participate in all testing procedures but not perform any training. Participants from all groups will be instructed to otherwise maintain their normal physical activity levels and dietary habits.

All training sessions will be supervised by research personnel at a Kennesaw State University fitness center. Participants will complete 2 training sessions per week for 8 weeks. Each training session will last about 45-60 minutes and consist of 5 exercises, including both multi-joint (leg press, chest press, back row) and single-joint (knee extension, bicep curl) exercises. Participants will perform 2 sets of 15 repetitions for each exercise for the first 2 weeks, then volume will be increased by progressing to 3 sets for the remaining 6 weeks. There will be a 60-second rest interval between sets and a similar tempo will be used between groups.

Both training groups will perform the same training protocol, but participants in the maximal mental effort group will mentally urge their muscles to contract maximally during each repetition. That is, despite using a low intensity, participants will imagine the feeling of maximal muscle contraction of the primary muscles during each repetition.

Several measures of strength, neuromuscular function, physical function, and body composition will be measured before and after the training or control period.

Inclusion Criteria:

• Body mass index between 18.5 - 33 kg·m2
• No structured physical activity in past 2 years
• Any unstable condition contradicting exercise
• Independently walk with or without assistive device
• No significant cognitive impairment

Exclusion Criteria:

• Score of 22 or lower on Montreal Cognitive Assessment
• Missing more than 3 training sessions (training groups only)
• Pacemaker
• Unstable angina
• Symptomatic heart failure
• Uncontrolled arrythmias
• Uncontrolled hypertension (greater or equal to 160/90)
• Myocardial infarction in the past 6 months
• Uncontrolled type 2 diabetes
• Type 1 diabetes
• Severe or unstable pulmonary conditions,
• Currently on supplemental oxygen therapy
• Severe hearing loss or visual impairment
• Alzheimer's Disease or significant cognitive impairment
• Stroke in the past 6 months or ongoing stroke-induced motor impairment
• Any neurological (e.g., Parkinson's) condition affecting motor control
• Undergoing chemotherapy
• Surgery in past 6 months
• Musculoskeletal injury in the past 6 months
• Terminal illness
• Stage 3 or greater chronic kidney disease