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The standard pull-up (SPU) is an effective upper body resistance exercise used throughout the fitness community to build muscular strength. However, some athletes prefer activities that employ a wider range of muscles such as CrossFit which has become widely popular since the early 21st century. CrossFit introduced the kipping pull-up (KPU) which combines the SPU with a common move in gymnastics known as the "glide kip.” PURPOSE: The purpose was to compare overall EMG muscle activation, and kinematics between a SPU and a KPU. We hypothesized that the additional motion generated by the kipping action of the KPU would significantly reduce the muscle activation in the upper body muscles compared to the SPU, while increasing the activation of hip-flexor and abdominal muscles. METHODS: This study was a within-subject, randomized, counterbalanced design of 11 male subjects who actively participated in CrossFit and were familiar with both styles of pull-ups. They had a mean age of 30 years (± 3.35) (mean ± SE). Electrodes were placed on the: infraspinatus (IF), latissimus dorsi (LD), rectus abdominis (RA), external oblique (EO), tensor fasciae latae (TFL), biceps brachii (BB), iliopsoas (IL), and pectoralis major (PM). Reflective markers to measure kinematics were placed on the subjects’ right side: 8th rib, greater trochanter, knee axis of rotation, and lateral malleolus. Subjects performed a set of 5 SPU and 5 KPU in random order, while kinematics and muscle activation were recorded. Data were analyzed with paired samples t-tests. RESULTS: The following kinematic variables were significantly greater in KPU compared to SPU: Max hip angle (48.81 ± 6.80°, p<.001), max knee angle (56.52 ± 11.26°, p=.001), hip range (24.18 ± 3.54 cm, p<.001), average angular hip velocity (76.81 ± 9.58°/s, p<.001), and average angular knee velocity (127.23 ± 35.06°/s, p=.005). These muscles showed significant reduction in muscle activation from SPU to KPU: LD (5.86 ± 6.21%, p=.046) and BB (13.58 ± 5.62%, p=.018). Whereas, these muscles showed significant increase in muscle activation from the SPU to KPU: RA (16.60 ± 3.55%, p<.001), EO (14.57 ± 3.60%, p=.001), TFL (16.24 ± 7.33%, p<.001), and IL (44.54 ± 31.64%, p=.001). CONCLUSION: It was concluded that there were significant increases in muscle activation in the hip flexor and abdominal muscles, which generated a significant ant/post swinging. The significant reduction in upper body muscle activation was likely due to this added momentum. A KPU may be a better overall workout because it incorporates more muscles. Additionally, reduced upper body muscle activation could theoretically allow an individual to complete more repetitions with less fatigue.

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