The Snatch Quiz material PDF

The Snatch The snatch is the rst of the two lifts contested in weightlifting, in which the barbell is lifted from the oor to overhead in a single movement. With its unparalleled speed and extensive range of motion, it epitomises mechanical power—the performance of maxi...

The Snatch The snatch is the rst of the two lifts contested in weightlifting, in which the barbell is lifted from the oor to overhead in a single movement. With its unparalleled speed and extensive range of motion, it epitomises mechanical power—the performance of maximal work in minimal time—as well as technical precision. The fundamental pulling mechanics of the snatch apply to that of the clean, and learning the snatch is typically more dif cult than learning the clean or jerk for new lifters. Additionally, the wide grip of the snatch improves the ease of learning the proper interaction of the barbell and body in the extension. For these reasons, teaching the snatch rst is generally recommended—once a new lifter is reasonably comfortable with the snatch, the learning time for the clean and the jerk will be greatly reduced. For the initial learning progression for the snatch, athletes can use a length of PVC pipe or wooden dowel as a substitute for a barbell. A 5-foot length of 3⁄4” pipe or dowel will be of similar diameter to a bar, but will be light enough for any athlete to manage for large volumes of training drills, and for certain drills that will be dif cult if not impossible for some athletes even with an empty 15 or 20kg barbell. The inexpensiveness of PVC also allows the teaching of many athletes simultaneously. Even for strong athletes, some of the following drills will be impossible to perform correctly with a regulation barbell. A 5-10 kg technique barbell can be used with these athletes if one is available. Otherwise, PVC is the best starting point for these learning drills. Bear in mind that in the descriptions of these drills that follow, the “bar” refers to whichever implement is being used at that time by the athlete. fi fl fi fi fi  **The Receiving Position in the Snatch** The receiving position in the snatch is critical for safely supporting heavy loads overhead while ensuring technical consistency. Athletes must establish a structurally sound position and re ne their ability to achieve it consistently through progressive exercises. This summary covers key aspects of the receiving position, including grip placement, the overhead structure, and progressive snatch balance exercises. Grip Placement The snatch grip is wide, reducing the bar's travel distance from the platform to the overhead position. The optimal width is determined by where the bar rests in the hip crease when standing upright. This contact point should be just above the pubic bone to prevent painful collisions during lifts. Adjustments should consider individual proportions such as arm length, shoulder width, and torso-to-leg ratio. Bene ts of a Wider Grip: Reduces bar travel distance. Decreases shoulder mobility demands. Improves bar proximity during the third pull Drawbacks of a Wider Grip: Strains wrists and hands. Weakens structural integrity in the overhead position. Increases the chance of missing lifts behind. Bene ts of a Narrower Grip: Provides a stronger starting position. Reduces wrist strain and improves grip. Strengthens elbow and shoulder stability overhead. Drawbacks of a Narrower Grip: Increases bar travel distance. Demands more shoulder mobility. Slows the bar's turnover in the third pull. The Overhead Position To set the overhead position, hold the barbell across the back with a snatch-width grip, retract the shoulder blades, and press the bar directly overhead. The bar should sit above the base of the neck, with elbows oriented halfway between downward and backward. The wrists should remain relaxed, allowing the bar to rest in the palms behind the forearms’ midline. fi fi fi  Overhead Structure & Stability The overhead position must be actively maintained through: Scapular Retraction and Upward Rotation: The shoulder blades should lock onto the ribcage for stability. Arm Position: Arms should be fully extended, acting as rigid support columns. Wrist and Hand Position: The bar should rest in the palms with a relaxed grip, reducing wrist strain and improving control. Athletes with hyperextended elbows may bene t from greater skeletal support, while others must rely more on muscular stability. A proper grip prevents wrist strain and encourages elbow extension. If feasible, maintaining the hook grip may help sustain better barbell control. Horizontal vs. Vertical Action The nal phase of the snatch pull involves a vertical push against the bar, not a horizontal swing. This upward action helps the athlete stabilise the bar overhead and reduce forward bar movement. Encouraging athletes to think of “pushing up” rather than “swinging back” ensures better lift execution. The Overhead Squat The overhead squat mirrors the snatch receiving position. Athletes should: Position feet to align thighs and knees correctly. Keep hips over the heels. Maintain an upright torso with a slight forward lean. Postural control is essential when recovering from the squat. Athletes should push up on the bar while standing to ensure stability. Snatch Balance Progression A series of snatch balance exercises progressively builds speed, stability, and coordination: Pressing Snatch Balance: Begin with feet in the receiving position and the bar on the back with a snatch-width grip. Press into an overhead squat position without elevating the bar. Focus on proper bar path and elbow lockout. Drop Snatch: Start with feet in the pulling position. Push under the bar aggressively, locking out overhead as the feet reconnect with the platform. Aim for minimal bar elevation and maximal speed. fi fi  Heaving Snatch Balance: Perform a controlled dip and drive with the legs to unweight the bar. Push under the bar into an overhead squat while maintaining balance. Focus on minimal bar lift and an aggressive downward movement. Snatch Balance: Combine elements of previous exercises: dip, drive, transition the feet, and punch under the bar. Prioritise speed, bar stability, and proper overhead lockout. Key Takeaways 1. Establishing the Grip: Proper grip width depends on individual proportions and allows for secure bar positioning. 2. Achieving the Overhead Position: Maintain scapular stability, elbow lockout, and wrist relaxation. 3. Re ning the Overhead Squat: Ensure correct foot placement, upright posture, and minimal torso lean. 4. Snatch Balance Progression: Use progressive drills to build speed, coordination, and stability in the receiving position. Mastering the receiving position in the snatch involves combining technical precision, body awareness, and consistent practice. This progression ensures lifters are prepared to stabilise heavy loads overhead safely and effectively. fi  **Learning the Snatch** Mastering the snatch involves breaking the movement into distinct drills and positions, allowing athletes to focus on key phases of the lift. This approach builds a foundation of correct motor patterns, enabling uid and precise execution when the full snatch is performed. This summary outlines the essential components of learning the snatch, from the mid-hang position to advanced progressions like the power and split snatch. 1. Establishing the Mid-Hang Position The mid-hang position is where the bar rests at mid-thigh, just before initiating the second pull. It teaches balance, proper posture, and explosive power. Key Features: Body Position: Feet in the pulling stance, shoulders slightly in front of the bar, back arched, shins vertical, and knees slightly bent. Grip & Tension: Snatch-width grip with the hook grip engaged, arms passively extended, and lats tight to keep the bar close. Weight Distribution: Balance on the front edge of the heel. 2. Snatch Drills Progression a. Mid-Hang Snatch Jump Focuses on an explosive hip and knee extension while maintaining bar proximity. Begin in the mid-hang position. Perform a vertical jump, driving through the legs while keeping the bar close. Avoid countermovement—jump from the static position. b. Mid-Hang Snatch Pull Re nes the jump by incorporating a precise bar path and full extension. Perform an aggressive leg drive while extending the hips. Rise onto the balls of the feet with the shoulders behind the hips. Avoid swinging the bar forward by activating the lats. c. Tall Muscle Snatch Introduces the arm action of the third pull. Stand upright with the bar at arms’ length. Pull the elbows up and out while keeping the bar close. Turn the bar over into an overhead lockout. d. Scarecrow Snatch Focuses on pulling under the bar using the upper body. Start with elbows elevated and bar close to the chest. Aggressively turn the bar over while lifting the feet into the receiving position. Lock the bar overhead as the feet reconnect with the oor. e. Tall Snatch Combines the scarecrow snatch with an extended arm start. Start with the bar at arms’ length. Pull the elbows up and out while lifting the feet. Lock the bar overhead as the feet reconnect. fi fl fl  3. Assembling the Snatch The mid-hang snatch combines all previous drills into one continuous movement. Start Position: Mid-hang position with balanced feet and engaged lats. Execution: Push through the legs and extend the hips. Pull the bar close, lifting the elbows high and turning it over aggressively. Receive the bar in a squat position, locking out as the feet reconnect. 4. Handling Missed Snatches Learning how to miss safely is crucial for injury prevention. Forward Miss: Push the bar forward while jumping backward. Backward Miss: Keep the arms long, release the grip if necessary, and jump forward. 5. Snatch Variations a. Power Snatch The power snatch is a snatch variation where the bar is received above a parallel squat. Key Points: The receiving depth should be higher than a full squat. The feet should move into the normal snatch receiving stance. Bene ts: Develops explosive power, bar path accuracy, and aggressive turnover. Useful for lighter training days or athletes lacking mobility. b. Split Snatch The split snatch was historically the dominant style before the modern squat snatch. It’s still relevant for athletes with limited mobility. Footwork: The lead foot steps forward while the rear foot moves back into a lunge-like position. Utility: Helps athletes with mobility issues or those training split jerk footwork. Key Takeaways for Learning the Snatch 1. Master the Mid-Hang Position: This is the foundation of snatch success, ensuring optimal posture, balance, and bar proximity. 2. Progress Through Drills: Isolate each phase of the snatch, focusing on correct execution, balance, and timing. 3. Practice Full Extensions: Commit to full hip, knee, and ankle extension during the pull while maintaining bar proximity. 4. Pull Aggressively Under the Bar: Use arm action and bar path control to accelerate downward movement. 5. Receive With Precision: Lock the bar overhead and stabilise in the receiving position while keeping balance and control. 6. Miss Safely: Learn forward and backward bail-out techniques to avoid injury during heavy lifts. 7. Integrate Variations: Use variations to enhance speci c elements of the lift, including explosive power, technique re nement, and mobility compensation. fi fi fi ** Pulling from the Floor ** The pull from the oor is the nal stage in learning the snatch. After mastering the snatch from the mid-hang position, lifters progress to pulling from the oor, integrating the rst pull into the lift. This phase is challenging but manageable through a structured progression of drills designed to reinforce proper positioning, balance, and control. 1. Starting Position The snatch begins with a well-balanced starting position: Foot Position: Feet set under the bar with the balls of the feet directly below it. Grip & Arms: Use a snatch-width hook grip with arms internally rotated, elbows pointing outward. Back & Hips: The back must be arched tightly, with hips positioned anywhere from slightly below to above the knees, depending on the lifter’s proportions. Shoulders & Knees: Shoulders should be slightly in front of the bar, and knees should be pushed outward to allow a more upright posture. Correct starting posture is critical for optimal bar movement and injury prevention. Mobility limitations should be addressed as a priority. 2. Snatch Segment Deadlift The snatch segment deadlift reinforces critical pull positions: 1. 1-Inch Off the Floor: - Push through the legs without jerking the bar. - Keep back tight and shoulders slightly forward of the bar. - Maintain light bar contact with the shins. 2. Knee Level: - Continue leg drive, shifting weight slightly back. - The bar should be in contact with the knees, with shoulders still slightly in front. 3. Mid-Thigh: - Achieve the mid-hang position with vertical shins, bar against the thighs, and shoulders still forward. - Ensure balance is over the front edge of the heel. Lifters should practice sets of three reps, holding each position for three seconds to reinforce balance and correct posture. 3. Halting Snatch Deadlift This exercise removes pauses at the 1-inch and knee-level positions, requiring lifters to stop only at mid-thigh: Perform a controlled lift from the oor to mid-thigh. Pass through all key positions practiced in the segment deadlift. Maintain slow, deliberate movement to reinforce stability and balance. fl fi fl fl fi  4. Segment Snatch + Snatch Complex To build con dence, lifters practice a complex combining familiar movements: Perform a halting snatch deadlift with a pause at mid-thigh. Execute a mid-hang snatch from that paused position. Bring the bar back down to the starting position. Perform a complete snatch with a controlled rst pull. Focus on bar path, balance, and explosive second pull. This complex reinforces key elements while easing the lifter into the full snatch. 5. Performing the Snatch from the Floor The nal step is performing the full snatch: Execution: Start from the correct position with a tight back and balanced feet. Perform a controlled rst pull to mid-thigh. Without slowing the barbell, explode through the second pull, extending the hips and knees. Aggressively pull under the bar and lock out in the receiving position. Stand up with the barbell overhead until the knees and hips are full extended. Repetition & Load Management: Start with light weights (40-50% of body weight) to master form. Use sets of 2-5 reps with strict attention to technique. Progress gradually, emphasising quality over quantity. Common Issues & Corrections If lifters struggle with speci c aspects of the pull, they should revisit targeted drills like: Starting Position: Revisit setup posture if the initial lift is unstable. Segment Deadlift: If balance or bar path is off, return to paused lifts. Halting Deadlift: Use this to reinforce leg drive and bar proximity. Key Takeaways for Pulling from the Floor Master the Starting Position: Ensure correct posture, bar placement, and back tension before lifting. Drill Critical Pull Segments: Use the segment deadlift and halting deadlift to build positional strength. Smooth Transitions: Develop a seamless movement from rst pull to second pull through the segment snatch complex. Reinforce Full Snatch Technique: Perform the complete snatch with light loads, emphasising technique. Consistent Practice: Focus on precision, control, and repetition quality for lasting improvement. fi fi fi fi fi fi  **Understanding the Snatch** This detailed exploration of the snatch focuses on the technical elements necessary for pro cient execution. For athletes still developing fundamental skills, it’s advisable to concentrate on basic snatch drills, hang and power snatches, and foundational assistance exercises like squats and pulls before diving into these advanced concepts. Coaches should provide minimal theoretical instruction early on, emphasising practice and repetition. The Starting Position The snatch’s starting position is its foundation. A correct setup ensures optimal execution of the lift, while errors can cause signi cant technical issues down the line. The starting position must balance strength, mobility, and stability to allow an ef cient and powerful pull from the oor. Key Principles: 1. Optimising the Whole Lift: The starting position must support the entire snatch, not just the rst pull. Compromises may be necessary to maintain balance and ensure smooth transitions. 2. Consistency: Unlike slower lifts like the deadlift, there is minimal time for corrections in the snatch due to its explosive nature. Consistency in setup is critical. Universal Elements of the Starting Position: 1) Foot Position: Feet should be hip-width apart with toes turned out 10-20 degrees for optimal balance and mobility. A wider stance may be necessary for athletes with larger thighs or unique anatomical proportions. 2) Barbell Placement: The bar should be positioned over the balls of the feet. Adjustments may be needed for different leg-to-torso ratios. The bar should remain close to the shins but not touch them initially. 3) Leg and Knee Position: Knees should be pushed out, ensuring the hips are open and the back can stay upright. The knees should be slightly over the bar, similar to a squat. 4) Back Arch: The back should be fully extended from the lower back to the shoulders. Correct breathing and bracing ensure a rigid trunk, vital for force transmission. fi fi fl fi fi  5) Arm and Shoulder Position: Arms should hang vertically with elbows pointing outward due to internal shoulder rotation. The shoulders should be slightly in front of the bar to support balance and pull mechanics. 6) Head Position: The head should be upright, with eyes focused straight ahead or slightly upward. This encourages good posture and balance throughout the lift. The First Pull The rst pull lifts the barbell from the oor to mid-thigh, setting up the explosive second pull. Its main purpose is to position the lifter correctly for maximum power generation. Key Principles: 1) Balance the System: At bar separation, the lifter and barbell become one system that must stay balanced over the feet. The bar must move slightly back toward the lifter to achieve the correct balance point. 2) Smooth Bar Separation: The barbell should separate smoothly from the platform without being yanked. A controlled lift avoids disruptions in balance and ensures better force application. 3) Bar Path & Proximity: The bar should remain close to the legs without dragging against the shins or knees. The shoulders should stay slightly in front of the bar as it rises, ensuring an optimal bar path. Pull Mechanics: 1) Back Angle Maintenance: The back angle should remain relatively constant through the rst pull, with only a slight forward lean. Lifters should avoid excessive tipping or premature hip extension. 2) Arm Activity: The arms should remain passive and relaxed, acting as connectors between the torso and bar. Elbows should no stay extended naturally through the pull. fi fl fi  3) Speed and Acceleration: The rst pull should be deliberate but not excessively slow. Speed must increase as the bar rises, setting up an explosive second pull. Troubleshooting Common Issues: 1) Barbell Drift: If the bar swings away from the lifter, they may not be engaging the lats or maintaining a vertical bar path. 2) Early Arm Pull: If the arms bend too soon, the lifter should focus on extending through the hips and knees rst. 3) Premature Hip Extension: The hips should not rise faster than the shoulders. Focus on pushing through the legs and maintaining back tension. Advanced Considerations: 1) Shoulder Positioning: The shoulders should never be behind the bar during the rst pull. Staying over the bar longer helps maintain balance and power transfer. 2) Foot Pressure Management: Weight should be evenly distributed across the entire foot during the pull. A premature shift to the toes indicates an imbalance that must be corrected. 3) Correcting the Pull Path: Lifters should practice segment deadlifts and halting snatch deadlifts to master bar path control. Developing Technical Consistency Lifters should emphasise technical consistency through regular practice and corrective drills. Exercises like pulls from various heights, snatch balances, and segment snatches reinforce correct positions and timing. Training Recommendations: Start with light weights to re ne technique. Incorporate paused pulls and slow-motion reps to build strength and positional awareness. Progress to heavier lifts only after mastering the basics. fi fi fi fi The Second Pull The second pull in the snatch begins at approximately mid-thigh and serves as the most explosive phase of the lift. It is the primary source of barbell acceleration and elevation, generating up to 150-250% more power than the rst pull. This section details key technical principles, from initiating the second pull to achieving optimal bar height and transitioning seamlessly into the third pull. The Second Pull: Purpose and Timing The second pull maximises bar speed and elevation, enabling the lifter to transition smoothly into the third pull. While bar elevation is critical, the second pull’s ultimate goal is enabling the lifter to reposition under the bar. Bar speed typically peaks halfway through the second pull, emphasising the need for a seamless transition into the third pull. Key Timing Principles: No Pause or Hitching: Lifters must avoid pausing or hitching the bar at the thighs, which disrupts bar speed and ow. Continuous Movement: The second and third pulls should be treated as one continuous action. Explosive Extension: A powerful leg drive combined with violent hip extension ensures maximal bar acceleration. The Starting Position for the Second Pull The second pull begins in the mid-hang position with: Shins Vertical: Knees pushed back, ensuring optimal hip tension. Shoulders Over the Bar: This creates maximum leverage. Weight Over Front Edge Of Heel: Balanced posture prepares for explosive extension. Back Arched: A rigid, forcefully extended back is critical for transferring power. Double Knee Bend (Scoop) The double knee bend allows the lifter to re-bend the knees after the bar passes them, setting up a powerful nal extension. Execution: As the bar passes the knees, the lifter pushes the knees forward. The hips move into the bar, creating maximal tension. The shoulders remain over the bar to maintain balance. Common Errors: Premature Initiation: Initiating the second pull too early reduces bar speed. Excessive Knee Flexion: Bending the knees too much slows the lift. fi fl fi Bar-Body Contact The bar should stay in immediate proximity to the body. Correct bar-body interaction prevents the bar from swinging forward due to horizontal force. Ideal Contact Point: Hip Crease: The bar should make contact as the hips extend vertically. Errors to Avoid: Early Contact: Causes the bar to swing forward. Dragging the Bar: This slows the bar and disrupts the lift. Arm Activity and Bar Path The arms serve as passive connectors during the second pull. They remain relaxed but extended, enabling maximum force transfer from the hips and legs. Critical Arm Cues: Passive Elbow Extension: The arms should not actively pull the bar. Internal Rotation: Elbows must point outward to keep the bar close. Leg and Hip Extension The second pull is powered by coordinated extension of the hips and knees, maximising vertical force on the bar. Key Movements: Leg Drive: Push through the platform aggressively. Hip Extension: Snap the hips into the bar while keeping the shoulders back. Triple Extension: Full extension of the hips, knees, and ankles creates maximal bar speed. Errors to Avoid: Over-Reliance on Hips: This creates a forward bar path. Premature Leg Drive Cessation: This limits bar speed. Final Extension Position At full extension, the lifter’s body should be vertically aligned, with shoulders slightly behind the bar. Ideal End Position: Shoulders Behind Hips: This maximises bar elevation. Feet on the Balls: Heels should rise naturally during extension. Key Corrections: Avoid Over-Extension: Excessive backward lean can cause loss of balance. Prevent Jumping: The goal is bar elevation, not body elevation. Jumping Backward vs. Forward Backward Jumping: This can be a valid technical style if it naturally enhances balance. Forward Jumping: This indicates a technical error, typically from incomplete hip extension or inadequate leg drive. Ankle Extension and the Shrug Ankle Extension: Heels should lift naturally as a result of powerful leg drive. Avoid intentional plantar exion—it should be a by-product of full extension. Shrug: The shrug helps initiate the third pull. It should occur naturally, not as a separate, isolated action. Transition to the Third Pull The second pull concludes with the lifter fully extended and beginning the aggressive pull under the bar. This movement should be seamless, ensuring continuous bar elevation and smooth downward motion by the lifter. fl **The Third Pull** The third pull is the lifter’s aggressive movement under the barbell after completing the rst and second pulls. It involves relocating from full extension into the receiving position, typically an overhead squat. This segment is often misunderstood as merely "dropping under the bar." However, the third pull must be as dynamic and forceful as the preceding phases of the lift. Key Phases of the Third Pull 1. Pull Down Against the Barbell 2. Turnover of the Arms 3. Push Up Against the Barbell Momentum and Acceleration After the second pull, the barbell continues to rise due to its momentum. However, as the barbell's weight increases, this upward travel diminishes, making the third pull even more critical. Lifters must actively pull themselves down rather than relying on gravity. Core Mechanics: Retracting Hips and Bending Knees: Initiates the downward movement. Force Application Shift: The barbell’s inertia becomes the anchor, replacing the ground’s resistance used during the rst two pulls. The Role of the Arms The misconception that arms do not contribute to barbell elevation is incorrect. While lifters must avoid "rowing" the bar, the arms actively assist in pulling the body down and keeping the bar close. Key Points: Elbows Up and Out: Pulling the elbows up and out creates maximal downward speed. Aggressive Pull: A forceful elbow lift supports the correct bar path and body-bar proximity. Shoulder Blade Retraction: This ensures smooth arm movement and bar control. Foot Repositioning Proper foot movement is vital for balance and optimal squat stance. Key Points: Lift Feet Completely: Reduces ground resistance and allows repositioning. Aggressive Contact with the Platform: An audible stomp signals strong reconnection. Avoid Isolated Knee Flexion: Ensure proper hip exion to keep the feet aligned. fi fl fi The Turnover Phase The turnover involves rotating the arms from above the bar to below it while maintaining bar proximity. Key Points: Elbows High and Stable: Prevent elbows from dropping prematurely. Maximal Speed and Aggression: Ensures ef cient movement under the bar. Close Bar Path: Maintains system balance and ef cient mechanics. The Push Up Phase Once the barbell is in its overhead position, the lifter must push up against it for stability and control. Key Points: Punch Straight Up: Finalise lockout while resisting barbell descent. Reconnection Timing: Aim to synchronise bar turnover with foot reconnection. Maintain Wrist Stability: Flip the wrists without sacri cing grip security. Bar Path and Body Position The barbell follows a slight S-shaped path due to the lifter's movement and the mechanics of the pull. Key Points: Maintain Proximity: Keep the bar close throughout the lift. Avoid Excessive Backward Lean: Minimise layback to preserve bar path control. Wrist Flexion: Allow natural wrist movement; avoid intentional exion. Receiving the Bar Securing the bar in the overhead position requires precision and active engagement. Key Points: Push Up and Sit Down Simultaneously: Create vertical stability. Maintain Core Pressure: Avoid releasing breath prematurely. Controlled Descent: Use the legs to absorb force while settling into a stable squat. Grip Width and Stability Grip width in uences barbell control and structural stability. Key Points: Wider Grip: Lowers the combined centre of mass but reduces structural integrity. Arm Angle: Keep a strong, supportive position to distribute load evenly. fl fi fi fi fl  Recovery Phase After securing the bar, the lifter must recover to a standing position while maintaining stability. Key Points: Lead with the Bar: Drive upwards while staying connected to the bar. Avoid Premature Drops: Hold the bar overhead for stability assessment. Correct Stance: Ensure feet are parallel before lowering the bar. Bar Path Analysis The bar path re ects the lifter's technical pro ciency and should follow a slight S-shape. Key Points: Start Over Balls of Feet: Initial backward movement aligns the bar with the lifter’s centre of mass. Barbell Rise: It peaks as the lifter completes the second pull. Minimal Drop: A short drop indicates ef cient movement under the bar. Bar Drop Considerations Bar drop is the distance the barbell travels downward from its maximal height in the pull, to its lowest position when received overhead in the snatch. Minimal bar drop is often a sign of a well-executed lift but should not be forced at the expense of barbell elevation. Key Points: Progressive Reduction: Bar drop should decrease as weights increase. Avoid Arti cial Limiting: Lifters should maximise bar elevation during lighter lifts to build power and speed. Targeted Drills: Use exercises like tall snatches or block snatches to enhance minimal bar drop ef ciency. fi fi fl fi fi