Your backstroke kick is the first thing to fall apart when fatigue sets in. The last 25 meters of a race, your legs feel heavy, your hips drop, and your entire stroke unravels. Most swimmers blame conditioning. The real problem is usually technique.
The backstroke flutter kick looks like a simple up-and-down motion, but it operates differently from a freestyle flutter kick. The muscles fire in a different sequence when you’re on your back, and the kick plays a role most swimmers underestimate. It’s not a propulsion machine. It’s the system that keeps your body aligned, your hips high, and your arms in a position to do their job.
What the Backstroke Kick Actually Does
Swimmers tend to think of the kick as a speed tool. Kick harder, go faster. That’s partly true in breaststroke, where the kick generates a large share of propulsion. In backstroke, the kick’s contribution to forward speed is modest, roughly 10 to 30 percent depending on the swimmer. That doesn’t mean it’s optional.
Your backstroke kick does three things. First, it adds some propulsion. Not a lot, but losing it drops your speed significantly because your body position deteriorates the moment your kick stops. Second, it keeps your hips and feet at the surface. Without an active kick, the lower half of your body sinks, creating drag that your arms can’t overcome no matter how hard you pull. Third, the kick helps your body rotate from side to side. That rotation is what allows your arms to pull and recover efficiently.
USMS compares backstroke without a solid kick to firing a cannon from a canoe. Your arms can generate force, but without a stable base, that force goes nowhere. Your rectus abdominis and obliques work alongside the kick to create that stable hip platform.
Why Is My Backstroke So Slow?
The most common reason is poor body position caused by a weak or inactive kick. When your hips and legs sink, they create drag that cancels out your arm propulsion. A steady, hip-driven flutter kick keeps your body near the surface and reduces resistance.
How the Backstroke Flutter Kick Works
The Up-Kick and Down-Kick
Your backstroke kick has two phases, and they are not equal. The up-kick—when your leg moves toward the surface—generates most of the propulsion. Your hip flexors and quadriceps drive this phase. The instep of your foot faces backward and pushes against the water. The motion starts at the hip, travels through a slight knee bend, and finishes with the foot flicking upward. Think of a whip cracking: the power starts at the handle and accelerates through the tip.
The down-kick, when your leg moves away from the surface, is powered by your hamstrings and glutes. Its main purpose is to reset the leg for the next up-kick. Keep the leg nearly straight during this phase—the movement should come from the hip. A common misunderstanding is that both phases produce equal propulsion. They don’t. The up-kick does the heavy lifting.
What Muscles Does the Backstroke Kick Use?
The up-kick relies on hip flexors and quadriceps. The down-kick uses hamstrings and glutes. Core muscles, specifically the rectus abdominis and obliques, stabilize the hips so the legs can kick effectively. Shin and ankle muscles also contribute to foot positioning.
Kick Size and Range of Motion
A bigger kick feels powerful. It’s also slower and creates more drag than speed. Your feet should stay inside the “shadow” of your body, a useful mental image. If your feet are breaking the surface or dropping well below your body line, the kick is too wide.
A smaller, faster kick beats a larger, slower one because it reduces frontal drag and keeps your stroke tempo high. The standard backstroke kicking pattern is six beats per arm cycle: three kicks for each arm stroke. A bigger kick slows this rhythm down, which means more time between arm strokes. Since your arms produce most of your propulsion, you want to maximize how often you use them.
Should My Feet Come Out of the Water During Backstroke?
Your toes can just break the surface on the up-kick, which is normal. But your feet should not splash above the water line regularly. Feet fully clearing the surface usually means the kick is too big or the swimmer is kicking from the knees instead of the hips.
How Many Kicks per Stroke in Backstroke?
Most backstroke swimmers use a six-beat kick, which means three kicks per single arm stroke or six kicks per full stroke cycle. This pattern provides the best balance of propulsion, body stability, and rhythm for sprint and middle-distance events.
Backstroke Kick vs. Freestyle Kick: What’s Different?
Both strokes use a flutter kick, but the mechanics flip when you roll onto your back. In freestyle, the down-kick (leg moving toward the pool floor) generates propulsion. In backstroke, the up-kick (leg moving toward the surface) is the propulsive phase. The “power kick” is reversed.
That reversal changes which muscles work hardest. Your hamstrings and glutes work significantly harder in backstroke because gravity pulls against them differently when your body is supine. Swimmers from a freestyle-heavy background often feel this immediately: the backs of their legs fatigue faster in backstroke than expected. That’s normal.
Knee bend patterns are different too. In backstroke, excessive knee bend pushes the knees above the water surface, which is visible and draggy. In freestyle, excessive knee bend drops the feet too deep below the body line. Coaches at Rocket Swim Club see this crossover issue regularly with swimmers across the Greater Toronto Area who train freestyle five days a week and add backstroke only occasionally. The posterior chain, hamstrings, glutes, lower back, needs separate conditioning for backstroke to work well.
| Backstroke Kick | Freestyle Kick | |
| Propulsive phase | Up-kick (toward surface) | Down-kick (toward pool floor) |
| Primary muscles | Hip flexors, quads (up-kick); hamstrings, glutes (down-kick) | Quads, hip flexors (down-kick); hamstrings (up-kick) |
| Posterior chain demand | Higher — gravity works against hamstrings and glutes when supine | Lower — gravity assists the recovery phase |
| Common visible error | Knees breaking the water surface | Feet dropping too deep below the body line |
| Body position | Supine (face up) | Prone (face down) |
Common Backstroke Kick Mistakes (and How to Fix Them)
These are backstroke-specific problems. Generic flutter kick advice rarely addresses what happens when a swimmer is on their back.
Kicking from the knees: This is the most frequent backstroke kick error. When the kick originates at the knee rather than the hip, the knees push above the surface on every cycle. That creates drag and kills the whipping action that generates propulsion. The fix: start every kick from the hip joint. Your leg should feel almost straight with only a slight bend at the knee.
Kicking too big: A wide kick feels powerful but creates more resistance than speed. The fix: think about kicking inside a narrow cylinder. Your feet should not move much beyond the vertical shadow of your body. Smaller and faster beats bigger and slower every time.
Stiff ankles: Ankle flexibility determines how much of your foot can push backward against the water. Swimmers with very stiff ankles sometimes move backward when kicking on their back without arms. The fix: use short-blade fins during kick sets to build range of motion. Ankle stretches on land help too.
Dropping the hips: When the kick stops between arm strokes, the hips sink and drag increases across your entire frame. The fix: keep the kick continuous. It should never pause, even during arm recovery.
Asymmetric kick: One leg kicking harder than the other pulls the body off its center line. You may not notice this yourself, but a coach watching from the pool deck will spot it immediately. The fix: single-leg kick drills, described below, expose and correct imbalances.
Why Do My Knees Come Out of the Water During Backstroke?
Knees breaking the surface almost always means you’re kicking from the knee joint instead of the hip. The knee bends excessively on the up-kick, pushing it above the water line. Shift the kick origin to your hip and keep the leg nearly straight throughout the motion.
| Stroke Analysis at Rocket Swim Club
Our coaches, former Moldova National Swim Team members Alina and Ivan, use Sportecos performance tracking to identify kick problems you can’t see yourself. If you’re in the Greater Toronto Area, book a private lesson for a full backstroke assessment. |
How to Tell if Your Backstroke Kick Needs Work
You don’t need a coach on deck to catch most kick problems. Here are five things you can check yourself during practice.
Look at your knees: If they’re breaking the surface consistently, you’re bending too much and kicking from the knee. The knees should stay underwater throughout the kick cycle.
Feel your hips: Does your kick pull your hips toward the surface, or do they sink between arm strokes? A properly functioning kick holds the hips up continuously. If you feel yourself sagging at the waist, the kick isn’t doing its job.
Do a wall test: Push off the wall on your back in streamline and kick only. If you barely move forward or drift backward, your ankle flexibility or kick mechanics need work.
Track your fatigue pattern: If your legs burn out well before your arms during a 100-meter backstroke, the kick is probably too big or too knee-driven.
Get a second pair of eyes: Ask a training partner or coach to watch from the side. Your feet should flutter just below the surface. If the movement looks like bicycle pedaling rather than a compact flutter, the knee bend is too large.
| Track Your Progress with Technology
Rocket Swim Club uses Sportecos technology to track swimmer performance data over time. Our coaches can show you exactly where your kick efficiency stands and how it changes as you improve. Visit rocketswim.com to learn more. |
Drills to Strengthen Your Backstroke Kick
Each drill below targets a specific problem from the mistakes section. Use them with intention, not just as warm-up filler.
Streamline kick on the back: Arms overhead in a tight streamline, kick on your back for 25-meter repeats. This drill forces hip-driven kicking because any knee-bending is immediately visible. It also trains body alignment—if your core relaxes, your hips drop and you’ll know. This is the best starting drill for backstroke body position and kick form.
Vertical kick: Treading water in a vertical position using only a flutter kick. Hands across the chest or above the water for added difficulty. This drill strips away momentum, so your kick has to keep your head above water on its own. Two to three sets of 30 seconds is a solid starting point.
Single-leg backstroke kick: Kick on your back with one leg while the other stays still, extended in line with the body. Switch legs every 25 meters. This drill exposes asymmetry between your right and left legs. If one side feels noticeably weaker or less coordinated, that’s exactly what you need to work on.
Fins drill: Use short-blade fins during backstroke kick sets. Fins build ankle flexibility, give immediate feedback on form, and let you feel what a correct kick should feel like. They are one of the fastest ways to improve backstroke kick mechanics.
How Can I Improve My Backstroke Kick?
Start with streamline kick on your back to build hip-driven form. Add vertical kick sets for power and short-blade fin work for ankle flexibility. Single-leg drills fix asymmetry. Consistency matters more than volume—include kick-specific work in every backstroke practice.
| Join Rocket Swim Club’s Programs
From Novice programs to competitive Junior, Senior, and Masters tracks, Rocket Swim Club offers structured training across multiple pools in the Greater Toronto Area. Our coaches incorporate backstroke-specific kick drills into every program level. Explore programs at rocketswim.com or email info@rocketswim.com to book a tryout. |
The backstroke kick isn’t about power. It’s about doing the right things in a small, controlled range of motion. Keep the kick hip-driven. Keep it compact. Keep it continuous. Those three principles solve most of the problems swimmers run into on their back.
If you’re building your backstroke from the ground up, read the full backstroke technique guide for how the kick fits into backstroke body position, the backstroke arm pull, and overall stroke timing.