# Impulse Leg Impulse Leg is an indicator on [Vela](https://vela.luxalgo.com/chart), our next-generation charting platform, written in Pine Script®. Classifies every completed zigzag leg against five impulse criteria (distance and speed versus the prior legs, directional candle share, bar overlap, and internal pullback) labeling confirmed impulses and near-miss candidates on the chart. Origin and extreme levels of the latest impulse anchor retracements and invalidation, and a dashboard scores the newest leg criterion by criterion. - Indicator in the LuxAlgo Library, by LuxAlgo, published Jun 3, 2026. - Access: free. - Concepts: [Impulse Leg](https://www.luxalgo.com/library/concept/impulse-leg/) (primary) - Open on Vela: https://vela.luxalgo.com/chart?pineScriptCodeId=b8tuap04v7npe2u3slmurn2v - Page: https://www.luxalgo.com/library/indicator/impulse-leg/ **Impulse Leg** classifies every completed leg of a swing zigzag against five measurable criteria and labels the qualifiers on the chart. Each leg is judged relative to its neighbors (travel and per-bar speed versus the prior legs' average, directional candle share, bar-to-bar overlap, and internal pullback) so an [impulse leg](https://www.luxalgo.com/library/concept/impulse-leg/) is recognized as traders read one: more ground in less time, one-sided, barely resting. ## How to Trade the Impulse Leg? - **Impulse label**: a fast, one-sided leg that also took out the prior same-side swing. Trend direction is defined by these. - **Candidate label**: dashed and faded: impulse quality without the structural break, an early sign of pressure building. - **Origin level**: the dotted line at the latest impulse's start doubles as invalidation. Price back through it fully unwinds the leg. - **Extreme level**: with the origin it frames retracement and projection measurements; hover a label for its statistics. The dashboard scores the newest completed leg criterion by criterion, so borderline classifications are transparent rather than binary. ## Impulse Leg Settings - **Swing Length** (default 10): bars each side to confirm a swing. - **Prior Legs to Compare** (default 4): the neighbor baseline legs are judged against. - **Min Distance Ratio** (default 1) and **Min Speed Ratio** (default 1.25): required multiples of the prior legs' average travel and distance per bar. - **Min Directional Candles %** (default 60): minimum share of candles closing in the leg direction. - **Max Bar Overlap %** (default 50): average overlap allowed between consecutive candle ranges. - **Max Internal Pullback %** (default 50): deepest pause allowed as a share of total travel. - **Break Requires Close Beyond Swing** (default disabled): require a close beyond the prior swing point. - Line width, labels, candidates, the swing framework, levels, and the dashboard are style options. ## Frequently Asked Questions ### What separates an impulse leg from a corrective leg? An impulse covers more distance in less time with one-sided candles; the [corrective leg](https://www.luxalgo.com/library/indicator/corrective-leg/) that follows is slower, overlapping, and retraces part of it. This build turns that contrast into thresholds, so the label is measured rather than eyeballed. ### Why did a fast leg only print as a candidate? It met every quality criterion but never took out the prior same-side swing point. The structural break is what confirms an impulse. Read candidates as pressure that has not yet broken structure. ### Do the labels repaint? A classification can upgrade while its end swing extends, so the current leg redraws. Once an opposite swing confirms, the leg locks; each classification alerts once per leg. ## Related indicators - [Smart Money Concepts (SMC)](https://www.luxalgo.com/library/indicator/smart-money-concepts-smc/) (Break of Structure): markdown at https://www.luxalgo.com/library/indicator/smart-money-concepts-smc.md - [Structure & Trend Dashboard](https://www.luxalgo.com/library/indicator/structure-trend-dashboard/) (Break of Structure): markdown at https://www.luxalgo.com/library/indicator/structure-trend-dashboard.md - [FVG + Liquidity Sweep + CISD](https://www.luxalgo.com/library/indicator/fvg-liquidity-sweep-cisd/) (Change of Character): markdown at https://www.luxalgo.com/library/indicator/fvg-liquidity-sweep-cisd.md - [MSS Sweep Fib Retrace](https://www.luxalgo.com/library/indicator/mss-sweep-fib-retrace/) (Change of Character): markdown at https://www.luxalgo.com/library/indicator/mss-sweep-fib-retrace.md - [HTF CISD Projections](https://www.luxalgo.com/library/indicator/htf-cisd-projections/) (Change of Character): markdown at https://www.luxalgo.com/library/indicator/htf-cisd-projections.md - [HTF Sweep Signals](https://www.luxalgo.com/library/indicator/htf-sweep-signals/) (Swing Failure Pattern): markdown at https://www.luxalgo.com/library/indicator/htf-sweep-signals.md - [Liquidity Structure & Order Flow](https://www.luxalgo.com/library/indicator/liquidity-structure-order-flow/) (Break of Structure): markdown at https://www.luxalgo.com/library/indicator/liquidity-structure-order-flow.md - [Market Structure Break & OB Probability Toolkit](https://www.luxalgo.com/library/indicator/market-structure-break-ob-probability-toolkit/) (Break of Structure): markdown at https://www.luxalgo.com/library/indicator/market-structure-break-ob-probability-toolkit.md --- Source: https://www.luxalgo.com/library/indicator/impulse-leg/ (LuxAlgo Library). Free to use with attribution: https://www.luxalgo.com/library/license/