Evaluating Abdominal and Lower-Back Muscle Activity While Performing Core Exercises on a Stability Ball and a Dynamic Office Chair
Bibliographic record
Abstract
OBJECTIVE: The purpose of this study was to evaluate the ability of a dynamic office chair to activate the core muscles while participants performed exercises sitting on the chair compared to a stability ball. BACKGROUND: Prolonged sitting has become an accepted part of the modern office. However, epidemiological evidence suggests that sedentary postures are linked to many adverse effects on health. The concept of dynamic or active sitting is intended to promote movement while sitting to reduce the time spent in prolonged, static postures. METHODS: Sixteen participants performed four pelvic rotation exercises (front-back, side-side, circular, and leg lift) on both a dynamic office chair and a stability ball. Muscle activity from 12 torso muscles were evaluated with surface electromyography. RESULTS: For all exercises, trunk muscle activity on the chair was comparable to that on a stability ball. The right external oblique was the only muscle to produce greater peak activity (p = .019) when using the ball compared to the chair (21.4 ± 14.0 percent maximal voluntary excitations (%MVE) and 14.7 ± 10.8 %MVE for the ball and chair, respectively). The left thoracic erector spinae produced greater average activity (p = .044) on the chair than on the ball. CONCLUSION: These findings suggest that this dynamic sitting approach could be an effective tool for core muscle activation while promoting movement and exercise while sitting at work. APPLICATION: Muscle activations on the dynamic chair are comparable to those on a stability ball, and dynamic office chairs can promote movement and exercise while sitting at work.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".