Hubbry Logo
Flutter kickFlutter kickMain
Open search
Flutter kick
Community hub
Flutter kick
logo
7 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Flutter kick
Flutter kick
Flutter kick
View on Wikipedia
from Wikipedia

The flutter kick is a kicking movement used in both swimming and calisthenics.

Swimming

[edit]

In swimming, the flutter kick refers to an alternating up and down movement of the legs.[a][1][2] It is seen in front crawl and backstroke.[3] The downbeat refers to the portion of each individual kick where the leg moves downwards, and the upbeat refers to the repositioning of the leg upwards.[1] In front crawl, the flutter kick is sometimes referred to as the front crawl kick, and in backstroke it is sometimes called the backstroke kick.[citation needed]

Phases

[edit]
The flutter kick in front crawl

In front crawl, the downbeat of each kick is initiated by the simultaneous action of bending the knee and flexing the hip to push down on the water with the thigh. The knee then extends forcefully, pushing the lower leg against the water until the leg is straight. The ankle then extends, pushing the foot into the water until it is inline with the rest of the leg. When the knee extends for the downbeat, it also has the effect of lifting the thigh and initiating the upbeat. Once the leg is straight, flexion at the hip lifts it up to be horizontal with the surface of the water, where it is in position to initiate another downbeat.[1]

The flutter kick in backstroke

In backstroke the movement is similar, but as the swimmer is on their back, their legs face upward. This means the downbeat of the front crawl kick corresponds to the upbeat of the backstroke kick, and that the upbeat of the front crawl kick corresponds to the downbeat of the backstroke kick.[1]

Effects

[edit]

Propulsion

[edit]

The kick allows the swimmer to propel themselves forward in the water though pushing back on the water with their feet.[1][4][better source needed] In his book Swimming Fastest, Ernest Maglischo says that the downbeat of the front crawl kick is "undoubtedly the most propulsive phase" and opines that the upbeat is probably not propulsive at all. This corresponds with the upbeat being the most propulsive phase in the backstroke kick.[1]

Research suggests that in front crawl, the power of the flutter kick produces the strongest propulsive force when no additional propulsion is present, and then decreases relatively proportionally to further increases in propulsion.[4]

In experienced competitive swimmers, the flutter kick can account for approximately 10–30% of propulsion during the front crawl,[vague] with the rest being generated by the arm stroke.[5][better source needed]

Rotation and stabilisation

[edit]

In Swimming Fastest, Maglischo writes that the lateral movements of the kick "probably" contribute to rotation and stabilisation in front crawl, aiding the swimmer in maintaining a straight course.[1] Some researchers argued that in front crawl, middle-to-long distance swimmers should use the flutter kick for stabilisation only, saying that the oxygen usage for a propulsive kick outweighs the potential increase in speed over longer distances.[6][1]

Variation

[edit]

Depth

[edit]

Maglischo opined that increasing the depth of the kick contributes to propulsion and stabilisation but also increases drag.[1] Kicking with a depth of 30 cm produced more propulsion than kicking with a depth of 15 cm,[1] and research suggests that high level competitive swimmers kick at a depth of around 40 cm.[b][7]

Foot angle

[edit]

Research suggests that a greater pitch angle (angle between the horizontal and the axis of the foot) increases propulsion by allowing the foot to push back on the water more. Athletes can increase this angle by improving their plantar flexion flexibility.[4][better source needed]

Training

[edit]

The flutter kick can be practised with a kickboard. Maglischo argues that training the flutter kick using a kickboard may neglect the lateral movements of the kick and hence not improve the rotation and stabilisation aspects.[1]

Underwater diving

[edit]

The flutter kick used with swimfins can be a powerful propulsion technique, and is used by scuba divers and freedivers underwater and at the surface, but there are other finning techniques more appropriate to some underwater environments and some types of fin. Divers in a confined environment or where silting may be a problem may use a modified flutter kick or frog kick, done entirely with bent knees, pushing water up and behind the diver to avoid stirring up sediment on the bottom.[8]

Calisthenics

[edit]

The calisthenics version of the flutter kick is often used as an intensive training tool in the military. They help to develop the hip flexors, abdominal muscles and leg muscles. Flutter kicks are a four-count exercise. Starting position is lying flat on the back with the feet and head approximately 6 inches (15 cm) off the ground. Hands are under the buttocks to support the lower back. Count one: raise the left leg to a 45-degree angle, keeping the right leg stationary. Count two: raise the right leg off the ground to a 45-degree angle while, at the same time, moving the left leg to the starting position. Counts three and four are repetitions of the same movements. Legs must be locked, with toes pointing away from the body.[9]

Notes

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Flutter kick

View on Grokipedia
from Grokipedia
The flutter kick is a basic propulsion and stabilization technique in , consisting of an alternating, up-and-down movement of the legs performed at a high rate over a small , primarily used in freestyle () and . It originates from the hips with relatively straight legs and pointed toes, creating a whip-like action where one leg kicks downward while the other returns upward, minimizing drag by keeping the feet near the water's surface. In proper execution, the downward kick (downbeat) is powered by the and hip flexors, extending the and accelerating through the ankle for a at the end, while the upward kick (upbeat) relies on the hamstrings and glutes with minimal bend to prepare for the next cycle. Kickers maintain a relaxed ankle position, with big toes nearly touching as feet pass each other, and heels occasionally breaking the surface for an efficient, fluttering rhythm that avoids excessive flexion or splashing. This motion emphasizes initiation over knee-driven kicking to promote smoothness and reduce . The flutter kick plays a crucial role in maintaining horizontal body position by counteracting the natural sinking of the hips, facilitating side-to-side for arm recovery, and contributing to forward propulsion, though it provides less thrust than the arms in freestyle. Common variations include the two-beat (two kicks per arm cycle, focused on rotation), four-beat (a hybrid pattern), and six-beat (six kicks per cycle, emphasizing propulsion and stability), with the six-beat being standard for most competitive swimmers. Drills such as kicking with a board or holding the pool edge help develop this technique, which is essential for overall efficiency and .

In Swimming

Definition and Purpose

The is a fundamental technique characterized by an alternating up-and-down movement of the legs, performed with relatively straight knees and pointed toes to maximize water displacement. This motion originates primarily from the hips rather than the knees, creating a whipping action that propels the swimmer forward while keeping the legs extended and close together within a narrow frame. For optimal execution, the legs maintain a slight natural bend at the knees to facilitate fluid, rhythmic motion, with flexible ankles ensuring the feet push backward against the water effectively. The primary purposes of the flutter kick include generating propulsion, stabilizing body position, and enhancing overall stroke efficiency, particularly in forward-facing strokes such as freestyle and . It contributes 10-15% to forward drive in by creating direct speed through the alternating leg phases, while also elevating the hips to reduce drag and maintain a streamlined horizontal alignment. Additionally, the supports rotational balance during arm pulls, allowing for smoother transitions and reduced energy expenditure across distances. Historically, the flutter kick evolved from early 20th-century developments in the crawl stroke, transitioning from the two-beat to more rapid six- and eight-beat variations by the and . It gained widespread popularity through American swimmer , who refined the technique in the with a focus on loose legs, hip-initiated motion, and a six-beat cycle, helping him set multiple world records and win Olympic golds in 1924 and 1928. This innovation marked a pivotal advancement in freestyle efficiency, influencing modern competitive standards.

Phases of Execution

The flutter kick in is executed through two alternating phases—the and upbeat—that occur continuously without pauses at the top or bottom of the motion to sustain forward momentum. These phases are driven primarily from the hips, with the legs moving in opposition: as one leg performs the , the other executes the upbeat, creating a rhythmic flutter. This alternation emphasizes small, rapid movements over a limited range, typically 12-18 inches deep, to optimize efficiency and reduce drag. In the downbeat phase, the leg moves downward from the surface, powered by hip flexion involving the and rectus femoris muscles, coupled with knee extension from the . The initially bends to about 120 degrees before straightening, allowing the plantar-flexed foot (toes pointed) to push backward against the in the first half of the motion, generating the primary forward thrust through a whip-like that ends at the ankle. is maximized as the upper side of the foot faces slightly downward and backward, displacing rearward. The upbeat phase follows immediately, lifting the opposing leg upward toward the surface via extension driven by the and hamstrings, with minimal bend to keep the leg relatively straight and streamlined. Water pressure aids in extension during this upward repositioning, while the pointed foot maintains tension; this phase contributes less direct thrust but preserves rhythm and prepares the leg for the subsequent downbeat, ensuring no loss of speed. Timing of the flutter kick is characterized by a continuous alternation at a frequency of 1-2 Hz, which supports efficient propulsion without excessive energy expenditure. In , kicks are patterned relative to the arm cycle, with variations such as the 2-beat (one kick per leg per cycle), 4-beat, or 6-beat (three kicks per leg per cycle, totaling six), where the latter aligns kicks with arm extension, insweep, and recovery for balanced rhythm. Coordination between the kick and upper body is essential for minimizing hydrodynamic drag and enhancing overall stroke efficiency. The downbeat typically synchronizes with the propulsive pull of the same-side arm, while the kick's lateral forces initiate body roll, rotating the torso 30-45 degrees per arm cycle to lengthen the stroke path and streamline the swimmer's profile during arm recovery. This integration ensures the legs contribute to stability and subtle propulsion, complementing the arms' dominant role.

Biomechanical Effects

The flutter kick generates forward thrust primarily through drag forces acting on the feet during the downward phase, with secondary contributions from lift forces created by the slight flexion at the ankle and . This mechanism contributes approximately 10-15% of the total forward speed in , as the legs produce a net propulsive force that supplements the arm stroke. The thrust can be approximated using the drag force equation: F=12ρv2ACdF = \frac{1}{2} \rho v^2 A C_d where ρ\rho is the density of water, vv is the velocity of the foot relative to the water, AA is the projected area of the foot, and CdC_d is the drag coefficient, which varies with foot orientation and speed. The alternating up-and-down motion of the flutter kick also produces torque around the swimmer's longitudinal axis, facilitating body roll of 30-45 degrees to each side during the stroke cycle. This rotation enhances stability by maintaining a streamlined position and reduces frontal drag by minimizing the cross-sectional area exposed to water resistance. In terms of energy efficiency, the flutter kick minimizes oxygen consumption relative to more demanding kicks like the or , as its rapid, low- motion reduces metabolic cost while sustaining and balance. Optimal kick , typically 0.4-0.6 meters, balances generation against increased drag from excessive leg excursion. Physiologically, the flutter kick primarily engages the hip flexors (including the ), , and to drive the alternating leg action, with supporting of the hamstrings and core stabilizers. Consistent use of this technique enhances cardiovascular by elevating and improving lower-body aerobic capacity over time.

Variations in Technique

Swimmers modify the standard flutter kick to optimize based on race distance, , or individual needs, adjusting elements like depth, foot positioning, and rhythm while maintaining the alternating up-and-down motion from the hips. In terms of depth, a shallow kick keeps the feet near the water's surface, minimizing drag for sprint events where speed is prioritized over sustained propulsion. Conversely, a deeper kick extends the legs to about 12 inches below the surface during the downbeat, enhancing propulsion for endurance swims but increasing resistance if not controlled. Foot angle variations involve neutral plantar flexion, with toes pointed to maximize the surface area for pushing backward during the propulsive phase, promoting across distances. For short races requiring rapid turnover, a slight dorsiflexion during the recovery (up-kick) phase allows quicker leg , though excessive dorsiflexion reduces overall thrust. Beat patterns differ by event demands: the 2-beat kick synchronizes one kick per arm cycle, conserving energy for long-distance freestyle by aligning with body rotation. The 4-beat pattern serves as a balanced hybrid, with one leg following a 2-beat and the other a 6-beat for moderate paces. The 6-beat kick delivers rapid alternation—three kicks per leg per arm cycle—for sprints, boosting speed through higher frequency. In , the flutter kick adapts with a wider and steady 6-beat or 8-beat , emphasizing the up-kick for while keeping movements compact to avoid drag. For transitions, such as in individual medley events, a brief flutter kick maintains during pullouts or turns, preventing pauses in leg action. Individual adaptations tailor the kick to ability levels; beginners often use shorter, smaller-amplitude kicks focused on hip initiation to build strength and reduce drag without overwhelming coordination. Advanced swimmers may incorporate fishtail-like variations, introducing a subtle motion from the knees for greater power in high-intensity efforts, enhancing thrust in competitive scenarios.

Training Methods

Training methods for the flutter kick emphasize isolated leg work to build foundational strength and technique before integrating it into full strokes. Basic drills often begin with a kickboard to isolate the legs and promote proper body position. For instance, swimmers perform 4 x 25-meter streamline flutter kicks holding an alignment kickboard, focusing on maintaining a horizontal body line and pointed toes, with a snorkel optional to eliminate breathing distractions and concentrate on leg action. To build endurance, 25-meter sprints with the kickboard at 85-90% effort, repeated 40 times on 40-second intervals, help develop sustained power without arm assistance. Vertical kicking in deep water further enhances core and leg strength; a common set involves 20 minutes of :45-second efforts followed by 15-second rests, alternating freestyle flutter kick with other patterns using equipment like DragSox for added resistance. Advanced progressions introduce tools and varied intensities to refine efficiency and speed. Fins-assisted kicks allow swimmers to develop a better "feel" for the water and longer strides, such as 16 x 25-meter kicks with fins and kickboard on 45-second cycles, alternating hard efforts on odd reps with 15-meter blasts on evens to build explosive power before transitioning to unassisted versions. Interval sets target and , like 20 x 50 meters consisting of 25 meters fast followed by 25 meters swim maintaining a consistent beat, on 2:00 intervals, which progressively increases while linking it to arm strokes. Common corrections address frequent technique flaws through targeted drills. To avoid excessive knee bend, which reduces propulsion, swimmers use snorkel-assisted kicks to focus solely on legs, emphasizing relatively straight knees and pointed toes during 25-meter repeats. For improving hip drive, side-kicking on the stomach—such as 2 x 25 meters per side with one arm extended on the kickboard—promotes rotation from the hips rather than knees, fostering a whip-like motion. Progression timelines typically start beginners with a 2-beat kick for efficiency and advance to a 6-beat pattern over 4-6 weeks through consistent practice. A study showed that 4 weeks of targeted 6-beat reduced 50-meter time trials by 10.21%, highlighting rapid improvements in . Integration with the full stroke occurs via combined sets, such as 20 x 100 meters (50 meters kick all-out, 50 meters swim) on 2:00-2:30 intervals, ensuring the flutter kick maintains rhythm during freestyle pulls.

In Other Contexts

Underwater Diving Propulsion

In underwater diving, the flutter kick serves as a primary propulsion method for scuba and freediving, enabling sustained horizontal movement while reducing disturbance to the surrounding environment. Divers employ a continuous, low-amplitude flutter kick to glide forward, which reduces the risk of kicking up sediment compared to higher-amplitude kicks and is particularly useful in clear open water away from the bottom where visibility is key. This technique is often favored over the frog kick for scenarios requiring greater speed, such as covering distances in currents, as it provides consistent thrust through rapid leg alternation. The technique involves a slower than surface to optimize use and air conservation in scuba contexts. With attached, divers initiate the motion from the hips, maintaining nearly straight legs and loose ankles to amplify efficiently through the fin blades. This straight-leg emphasis reduces unnecessary bending at the knees, promoting a streamlined body position that supports during prolonged submersion. In , the flutter kick similarly focuses on hip-driven propulsion to extend dive times by conserving oxygen. Key advantages include reduced hydrodynamic drag when performed in a horizontal, streamlined posture, which enhances overall efficiency and allows divers to maintain without frequent adjustments. However, the flutter kick has limitations in confined spaces, such as caves or wrecks, where its vertical fin motion can stir more readily than techniques, potentially reducing visibility. Additionally, it incurs a higher cost compared to passive , making it less ideal for extended stationary positioning or low-exertion dives.

Calisthenics Exercise

The flutter kick serves as a bodyweight exercise performed on land, targeting and lower body through controlled, alternating leg movements while lying . To execute it, begin by lying flat on your back on a or firm surface with your legs extended straight and arms positioned at your sides or placed under your glutes or hips for lower back support. Engage your by drawing your toward your spine, press your lower back into the floor to maintain stability, and lift both legs approximately 6 to 12 inches off the ground. Then, alternate small, rapid lifts of each leg in a fluttering motion, keeping the knees straight and movements originating from the hips rather than the knees, for durations of 20 to 30 seconds per set. This form emphasizes precision to avoid straining the lower back, with beginners starting at a moderate pace to build control. This exercise primarily strengthens the lower abdominal muscles (rectus abdominis), hip flexors (), and , while also engaging the glutes and obliques for stabilization. It enhances core endurance and lower body resilience without requiring equipment, making it suitable for (HIIT) circuits or integration into flows for improved postural alignment and through better hip mobility. Regular incorporation can contribute to toned abs and increased metabolic demand when performed dynamically, supporting overall fitness without the need for weights or machines. Variations include the single-leg flutter, where one leg remains elevated while the other performs the alternating motion to address muscular imbalances and intensify unilateral focus on the flexors and quads. For added difficulty, an elevated version raises the legs higher (to 45 or 90 degrees) before initiating the flutter, increasing core demand and quad activation; this can be progressed by lifting the head and shoulders into a hollow body position. Typical programming involves 3 sets of 30 seconds, gradually building to 60 seconds as endurance improves, with rest intervals of 15 to 30 seconds between sets to maintain form. The flutter kick on land originated as an adaptation of the propulsion technique during 20th-century fitness routines, transitioning from aquatic to dry-land bodyweight exercises for accessible core conditioning. It gained popularity in military programs, where it is valued as a challenging, equipment-free to build abdominal and endurance, often performed in group settings to foster discipline. This exercise has also been incorporated into Pilates-inspired mat work and protocols for its emphasis on controlled and core engagement.

References

  1. https://www.usms.org/fitness-and-training/guides/freestyle/kick
  2. https://interactiveacademy.org/docs/ia-swim-definitions.pdf
  3. https://troopleader.scouting.org/program-features/swimming/basic-swimming-strokes/
  4. https://www.usaswimming.org/news/2021/10/05/five-freestyle-tips-to-start-your-season
  5. https://www.traindaly.com/train-daly/blog/flutter-kick-technique-muscles-benefits
  6. https://www.nature.com/articles/s41598-020-65494-z
  7. https://coachsci.sdsu.edu/swim/bullets/carlhis3.htm
  8. https://www.aquaticsintl.com/facilities/johnny-weissmuller-twice-the-hero_o
  9. https://www.swimming.org/sport/history-of-front-crawl/
  10. https://www.researchgate.net/publication/233972563_Power_production_of_the_lower_limbs_in_flutter-kick_swimming
  11. https://effortlessswimming.com/this-is-what-happens-you-over-reach-and-over-rotate/
  12. https://espace.library.uq.edu.au/view/UQ:415833/UQ415833_postprint_OA.pdf
  13. https://blog.myswimpro.com/2023/01/09/how-to-improve-your-kick-in-swimming/
  14. https://www.sciencedirect.com/science/article/abs/pii/S0167945715300518
  15. https://www.kheljournal.com/archives/2025/vol12issue5/PartF/12-5-55-556.pdf
  16. https://www.usms.org/fitness-and-training/guides/backstroke/kick
  17. https://fitterandfaster.com/swim-videos/new-drill-breaststroke-arms-flutter-kick/
  18. https://swimlikeafish.org/6-styles-of-swim-kick-techniques
  19. https://swimswam.com/swim-workout-for-kick-technique-and-leg-strength/
  20. https://swimswam.com/swimming-kick-sets/
  21. https://swimswam.com/vertical-kicking/
  22. https://swimswam.com/six-beat-kick/
  23. https://www.scuba.com/blog/underwater-finning-kicking-techniques-scuba-diving/
  24. https://www.tdisdi.com/sdi-diver-news/choosing-the-right-kick/
  25. https://www.scubadiving.com/finning-techniques-all-divers-should-know
  26. https://www.divessi.com/en/blog/finning-techniques-for-divers-9089.html
  27. https://baliaqua.com/blog/scuba-diving-finning-techniques/
  28. https://dan.org/alert-diver/article/military-diving/
  29. https://www.bodi.com/blog/flutter-kicks
  30. https://www.nike.com/a/what-are-flutter-kicks
  31. https://www.runnersworld.com/training/a36353416/flutter-kicks/
  32. https://pva.org/wp-content/uploads/2022/01/GET-MILITARY-STRONG.pdf
Add your contribution
Related Hubs
User Avatar
No comments yet.