пятница, 23 января 2015 г.

Lower Body Power Surge

With Dumbbell Squat Jumps

Lower Body Power Surge
Need a few reasons to focus on increasing your lower body power? For one, it will allow you to jump and run with more authority on the basketball court or blast down the field in a pickup game of football. Two, developing a greater base of power can stimulate your balance and coordination while increasing your endurance and explosive strength, and burn a lot of calories to boot. And three, increased muscle strength typically leads to increased muscle size. So if you’re looking to build bigger legs and increase performance, dumbbell squat jumps are a great exercise to add to your workout.

ANATOMY LESSON

The squat jump involves all of your thigh, calf and hip muscles, but only the major muscles will be discussed here.
Lower Body Power Surge - With Dumbbell Squat Jumps

Quadriceps

The quadriceps femoris is a group of four thigh muscles1 that are hit especially hard by squat jumps. The vastus lateralis muscle covers the lateral part of the femur bone of the thigh. The vastus medialis muscle is anchored to the medial part of the femur. The vastus intermedius muscle is attached to the central, anterior part of the femur.1 The rectus femoris begins on the hip bones at the iliac crest and above the hip joint and not on the femur.2 The fibers from these three vasti muscles attach to the quadriceps tendon, which in turn connects to the patella (knee cap). This tendon continues as the patellar ligament and it anchors on the tibia bone of the lower leg. The four quadriceps muscles work together to extend (straighten) the leg at the knee joint. The rectus femoris is more effective as a knee extensor when the hip is almost straight.
Lower Body Power Surge - With Dumbbell Squat Jumps

Glutes

The gluteus maximus is the major muscle of the hip.1 It extends the thigh (moves it backwards) when you are jumping upwards from the squat position. The fibers of the gluteus medius muscle runs between the ileum bone of the hip and the posterior part of the femur bone of the thigh. It abducts the femur at the hip joint by moving the femur laterally, away from the mid-line of the body. The gluteus medius maintains body balance during the takeoff and landing of squat jumps.
Lower Body Power Surge - With Dumbbell Squat Jumps

Hamstrings

The long head of the biceps femorissemimembranosus and semitendinosus muscles comprise the hamstring muscles. These muscles attach to the posterior part of the hip and the pelvic bones.1 They extend down the posterior side of the femur bone to attach to the medial side of the tibia bone of the leg (semitendinosus and semimembranosus), or the lateral side of the tibia bone just below the knee (biceps femoris). Together these muscles flex the knee. However, when the foot is on the ground, the hamstrings extend (straighten) the hip joint, and therefore these muscles are very activated during the upwards leap in dumbbell squat jumps.
Lower Body Power Surge - With Dumbbell Squat Jumps

Calves

The calf musculature is invoked during the last phase of the jump upward on this exercise. The upper and middle regions of the medial gastrocnemius form the medial part of the calf below the knee.1 The lateral gastrocnemius forms the outer part of the calf. The soleus muscle is deep to the gastrocnemius muscle. The medial and lateral heads of the gastrocnemius muscle and the soleus fibers attach to the thick Achilles tendon at the back of the ankle, and these muscles plantar flex the foot at the ankle joint1 (i.e., raise the heel from the floor).
Lower Body Power Surge - With Dumbbell Squat Jumps

THE EXERCISE: DUMBBELL SQUAT JUMPS

1. Stand on a non-slip surface and take a medium-light dumbbell in each hand. Place your feet about shoulder-width apart.
2. Squat down until your knees are flexed to an angle of about 90 degrees.
3. Explosively and powerfully jump upwards as high as you can. Make sure that you go up on the tips of your toes at the top.
4. You will leave the floor momentarily, then come down. As soon as your feet hit the floor, immediately begin your squat downward, but slow the decent of your body, so that it’s a controlled squat back to the starting position.
5. Do not pause at the bottom, but immediately explode upwards for your next jump.6
6. Continue for a minimum of 15 repetitions. Rest about a minute then repeat the set. You can work up to four sets. Do not be too concerned about using heavier dumbbells too quickly.4

RX TIP

Dumbbell squat jumps are an explosive exercise, so the muscles and joints should first be warmed up appropriately. In addition, your shoes should have a good sole that will not slip when you are jumping upward.
The dumbbell squat jump can be a great complement to other resistance or aerobic training. Alternatively, they can work independently to effectively add power and strength to your lower body, while giving you greater jumping ability,improved ankle and Achilles tendon strength,8 or explosiveness in each step.

References

  1. Moore, KL and AF Dalley. Clinically oriented Anatomy. Fourth edition. Baltimore, Lippincott Williams & Williams, 1999; 531-546;571-592.
  2. Waligora AC, Johanson NA, Hirsch BE. Clinical anatomy of the quadriceps femoris and extensor apparatus of the knee. Clin.Orthop.Relat.Res. 2009; 467: 3297-3306.
  3. Pacheco L, Balius R, Aliste L et al. The acute effects of different stretching exercises on jump performance. J Strength Cond Res 2011;25:2991-2998.
  4. Randell AD, Cronin JB, Keogh JW et al. Reliability of performance velocity for jump squats under feedback and nonfeedback conditions. J Strength Cond Res 2011;25:3514-3518.
  5. Foure A, Nordez A, Cornu C. Effects of plyometric training on passive stiffness of gastrocnemii muscles and Achilles tendon. Eur J Appl Physiol 2012:112- 2849-2957.
  6. Iida Y, Kanehisa H, Inaba Y et al: Short-term landing training attenuates landing impact and improves jump height in landing-to-jump movement. J Strength Cond Res 2013;27:1560-1567.
  7. Ziv, G , Lidor, R 2009. Vertical jump in female and male basketball players-A review of observational and experimental studies. J.Sci.Med.Sport 2010;13, 332-339, 2010.
  8. Foure A, Nordez A, Cornu C: Plyometric training effects on Achilles tendon stiffness and dissipative properties. J Appl Physiol 2010;109:849-854.

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