• Korean Journal of Applied Biomechanics
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• v.32 no.2
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• pp.49-55
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• 2022

Objective: This study aims to verify the front squat motions using by two different surfaces, thereby elucidating the grounds for effective training environment that can minimize the risk of injury. Method: Total of 10 healthy male crossfit athletes were recruited for this study (age: 32.30 ± 3.05 yrs., height: 173.70 ± 5.12 cm, body mass: 82.40 ± 6.31 kg, 1RM: 160 ± 13.80 kg). All participants are those who know how to do front squats well with more than five years of crossfit athlete experience. All participants have sufficient experience in front squats on two types of surface which are soft surface (SS) and hard surface (HS). In each surface, participant perform 10reps of the front squat with 80% of the pre-measured 1RM. A 3-dimensional motion analysis with 8 infrared cameras and 2 channels of EMG was performed in this study. Paired sample t-test was used for statistical verification between two surfaces. The significant level was set at α=.05. Results: The significantly decreased rectus femoris muscle activation was found in SS compared with that of HS on phase 1 (p<.05). Also, ROM of ankle joint was significantly increased in the SS compare with that of HS on phase 1 (p<.05). The muscle activity ratio of gluteus maximus/rectus femoris showed a significant difference only in SS compared with that of HS on phase 1 (p<.05). Conclusion: In conclusion, Korean crossfit boxes should consider the use of hard surface, which has a relatively less risk of injury than soft surface, in selecting flooring materials. For the Crossfit athletes, they are also considered appropriate to train on a relatively hard surface.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.61-71
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• 2023

Purpose : Energy bars are increasingly popular among active individuals, yet their timing and nutrient combinations' impact on exercise adaptation remains unclear. This study aims to address this knowledge gap by investigating whether the combination of pre- and post-workout supplementation can synergistically enhance fitness and alleviate fatigue in trained CrossFit participants. Investigate if combining pre- and post-workout supplements can enhance fitness and blood lactate management in trained CrossFit participants, potentially improving exercise performance for this group. Methods : In a randomized crossover study, 20 trained CrossFit individuals (11 males, 9 females) completed thrice-weekly 60-minute CrossFit sessions for 3 weeks, with a one-week washout period. Participants were randomly assigned to either a chocolate bar group (CH, 45 g, 225 kcal) or an energy bar group (ES, 48 g, 238 kcal, with protein, caffeine, taurine, and BCAAs). For one week, participants consumed two bars of their assigned supplement five minutes before and after workouts. After a washout period, they switched supplements. Blood lactate levels and a visual analog scale (VAS) were assessed before, immediately after, and 30 minutes post-workout. Fitness tests (hand grip, broad jump, sit-ups) were conducted at baseline and 30 minutes post-final workout. Data were analyzed using two-way repeated measures ANOVA (p<.05), 95 % confidence intervals, and magnitude inferences. Results : Hand grip strength (t=-5.60, p=.000), broad jump (t=-3.43, p=.003) and sit up (t=-3.94, p=.001) were significantly increased in the ES group. Compared to CH group, there was a significant time and group interactions for blood lactate level (F=5.51, p=.008) and VAS(F=31.67, p=.000) in the ES group. Conclusion : Pre- and post-workout energy bar supplementation may have a beneficial effect on blood lactate clearance and fitness in trained CrossFit individual. The combination of proprietary supplements taken may provide benefits for removing the blood lactate during high-intensity functional exercise.

• The Journal of Korean Physical Therapy
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• v.35 no.6
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• pp.167-176
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• 2023

Purpose: Due to the high incidence of shoulder injuries, including shoulder impingement syndrome (SIS), among CrossFit practitioners due to frequent overhead movements, serratus anterior exercises are considered crucial for scapular stabilization in both intervention and prevention. Objective: The objective of this study is to compare the muscle activity and ratios of scapular stabilizing and shoulder girdle muscles between individuals with and without SIS during serratus punch and wall slide exercises, both targeting the serratus anterior muscle, in CrossFit training practitioners. Methods: Surface electromyography was used to compare the muscle activity and activity ratio of scapular stabilizing muscles and shoulder muscles during serratus punch and wall slide exercises in two groups of 20 CrossFit practitioners: ten with SIS and ten without symptoms. Results: The group with SIS showed higher activation of the pectoralis major, upper trapezius, and a higher pectoralis major/serratus anterior and upper trapezius/serratus anterior muscle activation ratio during the serratus punch exercise compared to the group without SIS. Similarly, during the wall slide exercise, the group with SIS exhibited higher activation of the upper trapezius and a higher upper trapezius/serratus anterior muscle activation ratio compared to the group without SIS. However, no significant difference in serratus anterior muscle activation was observed between the two groups. Conclusions: This study highlights the higher activation of the pectoralis major and upper trapezius muscles in CrossFit practitioners with SIS during the serratus anterior exercise, suggesting the importance of minimizing the overactivation of these muscles to prevent impingement syndrome in this population.