The lunge gets you into the front corners without stumbling. Learn to brake in control, protect knees and ankles and recover quickly.
The honest answer: The lunge is a big, controlled step forward with the racket-side leg that gets you to the net, lets you hit the shuttle and lets you push back with the same leg. In many cases it is faster than running because it covers distance in one step while also braking.
You need it constantly. A video analysis of singles matches found that about 15 % of all movements are lunges [2]. At the same time it is the step where your body works the hardest: a review of 20 studies shows that lunge biomechanics depend strongly on playing level, shoe and direction [1]. A lunge forward to the left produced the highest impact forces in a study with 15 players: about 2.3 times body weight [3].
That sounds like a lot, but it is no reason to worry: the body is made for it if you build technique and strength step by step.
Stand, take a big step forward with the racket-side leg and bend the front knee until it is over the foot. The back leg stays straight. Then push back. Repeat ten times per side.
Milestone: You stand stably without wobbling and come back without momentum.
Toes and knee point in the same direction, the knee does not collapse inwards. Place the foot softly. In a study with eight players per group, elite players showed more pressure on the inside of the forefoot, recreational players more on the outer edge of the forefoot [4]. The outer edge is the side where it is easier to roll the ankle; that is an inference, not a result of the study. So pay attention to a clean foot line.
Hang a shuttle (or a towel) at the net or have someone hold a shuttle in front of you. Extend the hitting arm forward and tap it. Your upper body stays upright and over the foot. Keep the racket loose.
Milestone: You touch the marker without throwing yourself forward.
The push back is at least as important as the step. A lab study with nine players compared three types of lunge: the step-in lunge demanded less of the muscles when pushing off than the kick lunge, while the hop lunge produced more power [2]. For getting started, the calm step-in is the safer choice. After the push-back, run to the centre in two steps.
Do shadow play: split step, lunge forward right, back, split step, lunge forward left, back. Ten rounds per session.
Milestone: Ten rounds without wobbling.
Put a line of tape parallel to the net at the distance of your lunge. Step in ten times and make sure your foot lands at the same distance from the line each time. This trains your step length by eye without having to think about every shuttle.
Take a big step with the racket-side leg, place the foot softly and keep the knee over the foot with the toes pointing the same way. Extend the hitting arm to the shuttle and then push back strongly. The upper body stays upright.
Keep the knee over the toes, do not let it collapse inwards, and land softly. Build reach and speed slowly and warm up. The load is high: up to about 2.3 times body weight on touchdown [3]. Strengthen thighs and hips.
Often the weight ends up on the outer edge of the foot, which recreational players loaded more than elite players in one study [4]. Pay attention to a clean foot line, soft landings and shoes with good grip. A coach can check your technique on video.
A video analysis in singles found about 15 % of all movements [2]. That is a lot, so it is worth learning cleanly early. Be patient: it takes time until step length and way back become automatic.
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