• 한국운동역학회지
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• 제32권2호
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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.

• International Journal of CAD/CAM
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• 제12권1호
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• pp.1-8
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• 2012

This study analyzes the characteristics of two different kinds of squat exercise through physical experiments and a computer simulation, i.e. one with a free weight and the other with a Smith machine are studied. This study also proposes a new design for the Smith machine, which has both the advantages of each type based on the results of the analysis. The muscle force and level of stimulation of the lower extremities during squatting were calculated by running an inverse dynamics analysis program on a musculoskeletal model together with the measured motion data. The calculated results were verified by comparing with the measured EMG data. The analysis showed that squatting using free weight is more effective than squatting using the Smith machine. Meanwhile, in order to design an improved Smith machine, which is the final goal of this study, the trajectory of the barbell of the subjects during free weight squatting was measured on the sagittal plane. The measurement showed that the average slope of the trajectory of the barbell is tilted backward by $10.7^{\circ}$. Based on this measurement, this study proposes a tilted design for an improved Smith machine.

• The Journal of Korean Physical Therapy
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• 제26권6호
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• pp.459-463
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• 2014

Purpose: The purpose of this study was to investigate the correlations between functional movement screen (FMS) and ankle dysfunctions in subjects with chronic ankle instability (CAI). Methods: This study was a cross-sectional study of 20 participants with CAI. The ankle dorsiflexion range of motion (ROM), Foot and Ankle Disability Index (FADI), center of pressure (COP) path length, and COP velocity for ankle dysfunction were measured in all the subjects. All the subjects underwent the FMS concerned with ankle functions consisted of deep squats, hurdle steps and in-line lunges. The Spearman rank-order correlation coefficient was used to determine relationship between the ankle ROM, FADI, COP and FMS. Results: The results of the deep squat and in-line lunge exercises revealed a significant correlation with the ankle dorsiflexion ROM, FADI, COP path length, and COP velocity. The hurdle step showed no correlation with the ankle dorsiflexion ROM and FADI but a significant relationship with the COP path length and COP velocity. Conclusion: The results of this study showed that relationship deep squat and in-line lunge and it is suggested that an assessment tool using ankle dorsiflexion ROM and ankle instability would be clinically effective.

• 한국융합학회논문지
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• 제11권2호
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• pp.271-279
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• 2020

스쿼트와 런지운동은 다양한 프리웨이트운동 중 몸통과 하체강화를 위한 중요한 운동으로 운동자세에 대한 이론적 근거 및 운동기준 동작의 확립을 통해 안전하고 효과적인 운동이 이루어져야 한다. 따라서 옵티멀 운동동작을 통한 부상 예방과 오류 동작에 대한 과학적 대응방안을 마련하기 위해 운동모형의 개발이 필요한 현실이며 이러한 목적으로 오류동작에 따른 자세교정을 위해 다양한 보조기구를 활용하는 방법이 효과적이다. 본 논문에서는 프리웨이트운동의 동적분석을 위해 지면반발력에 대응한 로드셀을 이용한 4포인트 하중검출을 통해 동적동작에 기반한 운동모형 분석시스템을 개발하고자 한다. 프리웨이트운동의 모형개발을 위해 동적 움직임을 단순화하여 구분동작에 따른 운동 모델링을 확립하고 동적인 동작분석을 통해 오류동작을 분석하고 보정하기 위한 수치정량화 데이터를 확보하였고 이를 활용할 수 있는 분석방법에 대한 타당성을 검증하였다.

• 한국운동역학회지
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• 제16권4호
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• pp.73-81
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• 2006

The purpose of this study was to investigate the effects of strength training on knee joint torque during walking in an adolescent with trisomy-21 Down syndrome. One adolescent with Down syndrome and one normal child participated in this study. Strength training consisted of eight exercises: squat, hamstring curl, hip adduction, hip abduction, knee extension, toe raise, sit-ups, and hyperextension of the waist. The participant with Down syndrome was participated in strength training for 12 weeks, three times a week, three sets, 10-15 RM; resistance was adjusted according to the principle of progressive overload. To measure the effect of strength training, isokinetic strength variables and knee joint torques were measured before training and after 12 weeks of training. The participant with Down syndrome had some abnormalities in controlling knee motion during walking due to muscle hypotonia, ligament laxity, and weakness of muscles. Post-training isokinetic strength increased compared to pre-training measurements. Knee range of motion were increased after strength training. Strength training did not affect ad/adduction and in/exteranl moments but did have an effect on flexor/extensor moment and timing.

• 대한물리의학회지
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• 제15권2호
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• pp.11-21
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• 2020

PURPOSE: This study examined the effects of posture improvement exercise using virtual reality programs on the posture and balance of patients with forward head postures. METHODS: Thirty men and women in their 20 s, who had a forward head posture, were divided randomly into a group with posture correction exercise and a group with posture correction exercise combined with virtual reality programs. The posture correction exercise was composed of squats, XCO training, and chin-tuck exercise. In contrast, exercise with virtual reality games involved the Hot Squat, Climbey, and Baskhead programs while wearing a headset. Both groups performed the exercises 15 min a day, three times per week, for four weeks. The balance ability, distance between the acromion and earlobe, and neck joint range of motion were assessed before and after the exercises. RESULTS: Both groups showed significant reductions in the distance between the acromion and the earlobe, along with significant improvements in the range of joint motion. The group that performed the virtual reality exercises showed a significant increase in the limit of stability. Both groups showed a significant decrease in the sway length. In contrast, the group given the virtual reality exercises showed a significant reduction in the sway speed while standing with their eyes closed. CONCLUSION: Exercise applying virtual reality programs can be used in clinical and home programs to correct the postures of individuals with a forward head posture because they can trigger interest in inducing active participation.

• 로봇학회논문지
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• 제16권2호
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• pp.86-93
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• 2021

This paper proposes a controller to regulate the supply pressure of the hydraulic power unit (HPU) for driving a bipedal robot. We establish flow rate models for charging accumulator, actuating joints and leaking from actuators and spool valves. This determines the pump driving motor speed to satisfy the demanded flow rate for operating the bipedal robot without the energy loss caused by the bypass through a pressure regulating valve. We apply proposed controller to an onboard HPU mounted on top of bipedal robot platform with twelve degrees of freedom. We implement air-walking motion and squat motion which require variable flow rate to the bipedal robot. Through this experiment, the energy efficiency of proposed controller was verified by comparing the electric energy consumed when the controller was applied and when the pump operated at constant speed. We also shows the capability of the HPU's control performance to regulate supply pressure.

• 한국응급구조학회지
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• 제8권1호
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• pp.169-178
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• 2004

본 연구의 목적은 응급구조사들이 긴 척추고정판을 이용하여 환자를 들어 올리는 3가지 다른 자세와 다른 3가지 부하 조건을 이용하여, 요추 4번과 5번의 압축력, 전단응력 그리고 합력의 변화를 동역학적 모델을 제시하기 위한 분석이다. 연구방법 : 36명의 남자가 본 연구의 실험에 자발적으로 동원되었으며, 나이는 평균 21.42세이고, 신장은 평균 174.05cm이며, 체중은 평균 78.05kg이다. 이 실험에서 부하 조건은 50, 70, 90kg이고, 들어 올리는 높이는 지상에서부터 95cm 이었으며, 들어 올리는 동안의 회전고리는 110cm이었다. 운동현상학적 자료는 2-D ProReflex Motion Capture Camera을 이용하였으며, sampling rate는 60Hz로 하였다. 결과 및 논의 : 동역학적 데이터 자료를 근거로 한 본 연구의 결론은 다음과 같다. Lunge 자세기술에서 전단응력과 합력 등이 최소의 stress로 요추 4번 5번에 미치는 것으로 나타났다. 그러나 Lunge 기술에서 압축력은 약간 증가되는 것으로 나타났다. 이 연구에서 Stooped 자세기술에서는 아주 큰 전단응력과 합력 등이 요추 4번, 5번 관절에 넓게 작용하는 것으로 나타났으며, 이는 들어 올리는 동작을 할 때 상해의 원인이 된다고 사료된다. 특히 응급구조사들이 들것을 들어 올릴 때 너무 큰 전단응력이 요추 4번, 5번 관절에 작용을 하면 비정상적으로 병리학상 또는 해부학상 신체적변화가 온다고 해석할 수 있다. 그래서 응급구조사들에게 들것을 들어올리는 stooped 자세는 아주 크고 많은 합력 작용하기 때문에 권고될만한 기술이 아니라고 해석 된다. Squat 자세에서 중간 정도의 압축력, 전단응력 그리고 합력이 작용된다. 만약 응급구조사가 전단응력 그리고 합력이 요추에 미치는 영향이 가장 걱정된다면, lunge 자세가 두 가지 힘을 줄여줄 수 있다고 사료된다. 마지막으로 응급구조사가 들것을 들어올리는 데는 squat 자세 기술이 가장 좋다고 사료 된다.

• 디지털융복합연구
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• 제14권6호
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• pp.513-518
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• 2016

다양한 연구결과에도 불구하고 전신진동운동이 인체에 미치는 기전은 명확히 제시되고 있지 않으며, 진동이 하지관절의 운동역학적 변화에 대해 분석한 연구는 미비한 실정이다. 그러므로 이 연구는 어떠한 하지관절의 운동역학적 변인이 수직점프 능력에 영향을 미치는지 분석하고자 한다. 최근 6개월간 하지에 정형외과적 병력이 없는 건강한 성인 남성 5명과 여성 5명은 5분간 30Hz의 전신진동운동을 실시한 전 후로 스쿼트 점프를 각각 3회씩 실시하였고, 수직점프 시 하지관절의 운동역학적 변화를 분석하기 위하여 3D 영상분석 시스템을 활용하였다. 대상자들의 스쿼트 점프 높이는 전신진동운동 처치 이후 향상되는 것으로 나타났으며, 발목과 무릎관절에서 하지관절 모멘트와 파워가 증가하는 것으로 나타났다. 그러나 지면반력 값과 엉덩관절의 모멘트와 파워는 전신진동운동의 처치 전 후에 통계적으로 유의한 차이가 나지 않는 것으로 나타났다. 30Hz의 전신진동운동을 실시한 결과 발목과 무릎관절은 진동이 인체내 긍정적인 영향을 미치는 것으로 나타났으나 엉덩관절의 경우 부정적인 영향을 미치는 것으로 나타났다.

• 대한물리치료과학회지
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• 제29권1호
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• pp.47-54
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• 2022

Background: Plyometric exercise is an exercise exerting forceful power in a brief period using isotonic activation. It is effective to improve reaction of muscle, agility, endurance and athletics performance. Weight training is an exericse improving muscular strength, endurance and respirating ability applying diversely in frequency and load of exercise Plyometric exercise and Weight training is to facilitate the athletics performance though improving the function of lower limb muscle, there is a difference that Plyometic jump squats is the way to improve agility and Weight training is the way to improve muscular strength. Therefore, it is necessary to know how this difference effects on athletics performance as measuring ankle, ROM, and jumping ability. Design: Randomized controlled trial. Method: This study was conducted with the voluntary participation of 40 university students, who were randomly assigned to jump squat and calf raise groups (n=20 per group). For each subject, we measured the range of motion of the ankle joint before and after exercise, as well as a standing broad jump and vertical jump test performance. We compared the performance indices before and after exercises using paired t-tests, and between groups using independent-samples t-tests. Conclusions: Both jump squat and calf raise exercises improved ankle joint dorsiflexion and plantar flexion, as well as standing broad jump and vertical jump height performance. However, there were no significant differences before versus after exercise, or between exercise types. Although jump squats and calf raises have different purposes, it is thought that, in combination, these exercises improve performance more effectively than either alone, and that such a combined exercise program improves the quality of training in both the general public and athletes in various sports.