The Effects of Caffeine on Human Spinal Motoneurons
- Conditions
- Healthy
- Interventions
- Dietary Supplement: Decaffeinated coffeeDietary Supplement: Coffee
- Registration Number
- NCT04891393
- Lead Sponsor
- Temple University
- Brief Summary
This study evaluates the effects of orally ingested, commercially available, coffee (3 mg/kg of caffeine) on the excitability of human spinal motoneurons of the lower leg.
- Detailed Description
Recently, it has been shown that human spinal motoneurons do not simply act as a binary control system. Instead, they are regulated by intrinsic properties that can elicit lingering effects on the descending motoneuron. Caffeine, one of the world's most popular over-the-counter supplements, can potentially augment these characteristics of motoneurons. Using decomposition software and non-invasive, high-density surface electromyography, it is possible to extract the characteristics of these motoneurons. This project will utilize a double-blind, inactive-placebo controlled, crossover design study to examine and quantify the effects of caffeine on motoneuron excitability.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 20
● Between 18 and 70 years of age
- Significant neurological or orthopedic injuries, which may limit volitional torque generation in the tested muscles.
- Significant change in the subjects' health or treatment in the past month.
- Known history of cardiovascular pathology (to include: uncontrolled hypertension, cardiac arrhythmias) or medical restrictions to caffeine ingestion.
- Allergies or dislike of coffee.
- Women who are pregnant will be excluded due to potential forces at trunk from pelvic safety harness and due to potential adverse effects of caffeine on the developing child.
- Women who are breastfeeding will be excluded due potential adverse effects on the breastfeeding infant from caffeine administration.
- Adults unable to consent, minors, pregnant women, and prisoners will not be included.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Inactive Placebo Decaffeinated coffee Single-dose, orally ingested, instant decaffeinated coffee (equal weight to intervention dose). Caffeine Coffee Single-dose, orally ingested, instant coffee.
- Primary Outcome Measures
Name Time Method Motoneuron excitability (Delta-f) Measured repeatedly at set intervals; Pre-Intervention & 30, 60, 90 minutes post-Intervention Changes in motorneuron excitability, as quantified by Delta-F values. A paired motor unit technique will be utilized (Gorassini et al., 2002). (Typically, these values range from -5 to +10).
- Secondary Outcome Measures
Name Time Method Motor Unit Recruitment Threshold Measured repeatedly at set intervals; Pre-Intervention & 30, 60, 90 minutes post-Intervention Changes in motor unit recruitment threshold. As assessed by determining the amount of force (percentage of maximum volitional force output) needed to recruit an individual motor unit.
Coherence Measured repeatedly at set intervals; Pre-Intervention & 30, 60, 90 minutes post-Intervention Changes in coherence values. Coherence provides a normalized value of the strength of correlation in the frequency domain. The magnitude of the correlation of the Fourier transforms of two spike trains is squared producing a value between 0 and 1, with 1 corresponding to a perfect linear prediction at a particular frequency (Rosenberg et al., 1989). This will be calculated using the composite spike train (Negro \& Farina, 2012) and, finally, z-transformed to allow for between-trial comparisons.
Motor Unit Discharge Rate Measured repeatedly at set intervals; Pre-Intervention & 30, 60, 90 minutes post-Intervention Changes in motor unit discharge rate. This is a single value that ranges from, approximately, 0 to 30.
Trial Locations
- Locations (1)
Temple University
🇺🇸Philadelphia, Pennsylvania, United States