Leg extension
 | This article relies largely or entirely on a single source. (December 2013) |
The Leg Extension
The leg extension is an exercise that focuses on the quadricep muscle and is usually performed sitting down. The exercise starts when the person sits comfortably on the seat with their back firmly against the backrest and their feet securely under the leg pads. They then select the appropriate amount of weight. After setting the weight, the person starts extending their legs until their legs are parallel to the ground. They will hold that position to briefly engage their quadricep muscles. They will then slowly lower the weight down, returning to the starting position. The resistance on the machine comes from weights which, depending on the manufacturer, is either pin loaded or plate loaded. The difference between the two is how you load the weights. The leg extension exercise is an effective approach to strengthen the quadricep muscles. It is also a good compliment to the squat exercise as they both work on the quadricep muscle. However, it is not something that can replace the squat exercise because of the fact that the leg extension isolates the quadriceps, on the other hand, the squat exercise targets the gluteal muscles, thighs, calves, and quadriceps.[1]
Creator
Jack LaLanne stands as an iconic figure revered for his groundbreaking contributions to exercise science and strength training. Lalanne is celebrated as a pioneering fitness coach and esteemed bodybuilder. Among his many transformative innovations, LaLanne is widely credited with inventing the leg extension machine, an essential piece of equipment utilized in gyms worldwide for strengthening the quadriceps muscles through controlled leg extensions against resistance. Many people think that LaLanne recognized the importance of targeting and strengthening the quadriceps muscles, which play a crucial role in lower body movements and overall athletic performance. In response to this, he may have conceptualized the idea of a machine specifically designed to isolate and work the quadriceps through controlled leg extensions. [2]
Frequent Errors
Many mistakes are frequently seen when people use the leg extension machine and do the related exercise. One such error is executing the exercise too fast. Executing the exercise too rapidly proves detrimental as it generates momentum, diverting focus away from the targeted muscle group. Another common error involves overloading the machine with excess weight. The reason overloading the machine with excess weight is a mistake is because excess weight can put strain on the knee joint and cause injuries. An additional mistake many people make when using the leg extension machine relates to improper posture, specifically arching or slouching and failing to keep their back on the backrest throughout the usage of the machine. Such posture may result in discomfort or injury in the lower back region. Many trainers also caution those who have preexistent knee problems from doing the leg extension exercise. Poor form during the exercise can have serious consequences, including the risk of knee injuries or worsening quadriceps muscle problems. These outcomes can impede progress and reduce the efficacy of the training program. Prioritizing proper form and technique throughout exercise is essential to reducing the chance of injury and optimizing the benefits of the workout.[3]
Risk of injury
Some fitness professionals and coaches advise people to not use an isolating leg extension machine due to the unnatural pressure it places on the knees and ankles.[4][better source needed]. However, this is a fitness myth based on largely anecdotal evidence rather than peer-reviewed research. Whilst there is some evidence that the leg extension's unnatural moment arm places constant tension on the anterior cruciate ligament (ACL),[5] there is no evidence to suggest that this constant tension increases injury risk outside of individuals with pre-existing ACL injuries. The leg extension is a good exercise for isolating muscular contraction in the quadriceps,[6] but as with all isolation exercises, should be included in a holistic resistance training program working all muscles, especially antagonistic muscle pairs (such as the quadriceps, hamstrings, and gluteal muscles), to avoid muscular imbalances, which are associated with increased injury risk.[7]
References
- ^ Shymechko, Ihor (2023-05-16). "Leg Extension Vs Leg Curl: Everything You Need To Know". Retrieved 2024-06-03.
- ^ "Why Jack LaLanne Is One of the Most Influential Athletes of All Time | BarBend". 2018-12-07. Retrieved 2024-06-03.
- ^ Team, The Wellyme. "Leg Extension: Execution, Benefits and Common Mistakes". www.wellyme.org. Retrieved 2024-06-03.
- ^ "6 Exercise Machines You Should do Without: The Seated Leg Extension". Archived from the original on 2015-03-06. Retrieved 2015-06-26.
- ^ Escamilla, Rafael F.; MacLeod, Toran D.; Wilk, Kevin E.; Paulos, Lonnie; Andrews, James R. (2012). "ACL Strain and Tensile Forces for Weight Bearing and Non—Weight-Bearing Exercises After ACL Reconstruction: A Guide to Exercise Selection". Journal of Orthopaedic & Sports Physical Therapy. 42 (3): 208–220. doi:10.2519/jospt.2012.3768. PMID 22387600.
- ^ Signorile, Joseph F.; Lew, Karen M.; Stoutenberg, Mark; Pluchino, Alessandra; Lewis, John E.; Gao, Jinrun (2014). "Range of Motion and Leg Rotation Affect Electromyography Activation Levels of the Superficial Quadriceps Muscles During Leg Extension". Journal of Strength and Conditioning Research. 28 (9): 2536–2545. doi:10.1519/JSC.0000000000000582. PMID 25148303. S2CID 10295500.
- ^ Croisier, Jean-Louis (January 2004). "Muscular imbalance and acute lower extremity muscle injuries in sport : Review article". International Sportmed Journal. 5 (3): 169–176.
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