scholarly journals Adaptive Admittance Control Scheme with Virtual Reality Interaction for Robot-Assisted Lower Limb Strength Training

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 301
Author(s):  
Musong Lin ◽  
Hongbo Wang ◽  
Jianye Niu ◽  
Yu Tian ◽  
Xincheng Wang ◽  
...  

Muscle weakness is the primary impairment causing mobility difficulty among stroke survivors. Millions of people are unable to live normally because of mobility difficulty every year. Strength training is an effective method to improve lower extremity ability but is limited by the shortage of medical staff. Thus, this paper proposes a robot-assisted active training (RAAT) by an adaptive admittance control scheme with virtual reality interaction (AACVRI). AACVRI consists of a stiffness variable admittance controller, an adaptive controller, and virtual reality (VR) interactions. In order to provide human-robot reality interactions corresponding to virtual scenes, an admittance control law with variable stiffness term was developed to define the mechanics property of the end effector. The adaptive controller improves tracking performances by compensating interaction forces and dynamics model deviations. A virtual training environment including action following, event feedback, and competition mechanism is utilized for improving boring training experience and engaging users to maintain active state in cycling training. To verify controller performances and the feasibility of RAAT, experiments were conducted with eight subjects. Admittance control provides desired variable interactions along the trajectory. The robot responds to different virtual events by changing admittance parameters according to trigger feedbacks. Adaptive control ensures tracking errors at a low level. Subjects were maintained in active state during this strength training. Their physiological signals significantly increased, and interaction forces were at a high level. RAAT is a feasible approach for lower limb strength training, and users can independently complete high-quality active strength training under RAAT.

2014 ◽  
Vol 41 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Alberto Carvalho ◽  
Paulo Mourão ◽  
Eduardo Abade

AbstractThe purpose of the present study was to identify the effects of a strength training program combined with specific plyometric exercises on body composition, vertical jump (VJ) height and strength development of lower limbs in elite male handball players. A 12-week program with combined strength and specific plyometric exercises was carried out for 7 weeks. Twelve elite male handball players (age: 21.6 ± 1.73) competing in the Portuguese Major League participated in the study. Besides the anthropometric measurements, several standardized jump tests were applied to assess VJ performance together with the strength development of the lower limbs in an isokinetic setting. No significant changes were found in body circumferences and diameters. Body fat content and fat mass decreased by 16.4 and 15.7% respectively, while lean body mass increased by 2.1%. Despite small significance, there was in fact an increase in squat jump (SJ), counter movement jump (CMJ) and 40 consecutive jumps after the training period (6.1, 3.8 and 6.8%, respectively). After the applied protocol, peak torque increased in lower limb extension and flexion in the majority of the movements assessed at 90°s-1. Consequently, it is possible to conclude that combining general strength-training with plyometric exercises can not only increase lower limb strength and improve VJ performance but also reduce body fat content.


CHEST Journal ◽  
1980 ◽  
Vol 78 (4) ◽  
pp. 618-621 ◽  
Author(s):  
Charles Kanakis ◽  
Robert C. Hickson

2020 ◽  
Vol 18 (3) ◽  
pp. 63-69
Author(s):  
Herikison Dias Rodrigues ◽  
Guilherme Moreira Caetano Pinto ◽  
Bruno Pedroso

OBJETIVO: O objetivo deste estudo foi comparar o desempenho no teste de potência de membros inferiores e flexibilidade de atletas de voleibol do gênero feminino, categoria sub-16, submetidas exclusivamente ao treino de força com atletas submetidas ao treino de força e flexibilidade.MÉTODOS: As atletas foram divididas em dois grupos. Um grupo realizou o treinamento de força (GTF) e o outro grupo efetuou o treinamento de força e flexibilidade (GTFF). O período de treinamento foi de dois meses. Para a avaliação da potência de membros inferiores e flexibilidade optou-se, respectivamente, pelo teste de salto horizontal e sentar-e-alcançar. Verificou-se a normalidade dos dados através do teste de Shapiro-Wilk. Alicerçado nestes resultados, utilizou-se o Anova two way, com post hoc de Sidak, para duas amostras independentes a fim de identificar o efeito do treino nos testes de salto horizontal e sentar-e-alcançar. O teste de Mann Whitney foi utilizado para verificar a diferença da melhora entre grupos no teste de força, e o teste t independente para verificar a diferença da melhora entre grupos do teste de sentar-e-alcançar.RESULTADOS: Verifica-se que houve diferença entre as médias entre as diferentes avaliações (tempo) no teste de salto horizontal [F(2,48)=10,282; p0,05] e flexibilidade [F(2,48)=10,298; p0,05). No salto horizontal a diferença significativa ocorreu no grupo GTF (p0,05). Na flexibilidade, a diferença significativa ocorreu no GTFF (p0,05). Na comparação entre grupos, o teste de Mann Whitney retornou valor de p=0,924 no teste de força. Não obstante, o teste t independente retornou valor de p=0,106 no teste de sentar-e-alcançar.CONCLUSÃO: Conclui-se que em face a importância da flexibilidade para atletas de voleibol, ainda que a GTFF não tenha apresentado melhora significativa no teste de impulsão vertical, não é possível refutar a utilização do treino de força aliado ao treino de flexibilidade.  ABSTRACT. Effects of different models of strength and flexibility training on the performance of the horizontal jump and sit-and-reach test in volleyball players.OBJECTIVE: This study aimed to compare the performance in the lower limb strength test and flexibility test of athlete of volleyball of the feminine gender, category sub-16, exclusively submitted to the strength training with athletes submitted to the strength training and flexibility training. METHODS: The athletes were divided in two groups. A group carried through the strength training (GTF) and the other group effected the strength training and flexibility training (GTFF). The period of training was of two months. For assessing lower limb strength and flexibility it was opted, respectively, for the horizontal jump test and to sit-and-reach test. It was verified normality of the data through the test of Shapiro-Wilk. Based in these results, Anova two way with post hock of Sidak was used to identify the effect of training in horizontal jump test and sit-and-reach test. For the difference between the initial and final test of each group, the Mann Whitney test was used to identify the difference of the improvement between groups in the strength test and independent test t was used to identify the difference of the improvement between groups of the sit-and-reach test. RESULTS: We found that there was a difference between the different test in the horizontal test [F(2.48)=10.282; p0.05] and sit-and-reach test [F(2.48)=10.298; p0,05). In the horizontal jump test there was a difference in GTF group (p0.05). In the flexibility test there was a difference in GTFF group. In the comparison between groups, the Mann Whitney test returned value from p=0.924 for the performance of the strength test. Besides that, independent test t returned value from p=0.106 for the performance of the flexibility test. CONCLUSION: We concluded that in view the importance of flexibility for volleyball athletes, it is not possible to refute the use of strength training combined with flexibility training.


2021 ◽  
Author(s):  
Dario Kohlbrenner ◽  
Céline Aregger ◽  
Martin Osswald ◽  
Noriane A Sievi ◽  
Christian F Clarenbach

Abstract Objective The purpose of this report is to describe the case of a patient with chronic obstructive pulmonary disease (COPD) who was load compromised and being referred for outpatient pulmonary rehabilitation. Low-load blood flow restriction strength training (LL-BFRT) was applied to prepare for and increase tolerability of subsequently applied high-load strength training (HL-ST). Methods (Case Description) A 62-year-old woman with COPD GOLD 2 B presented with severe breathlessness. Lower limb strength was severely reduced while functional exercise capacity was preserved. The patient was severely load compromised and had high risk to be intolerant of the high training loads required to trigger the desired adaptations. LL-BFRT was applied during the first 12 training sessions and HL-ST in the subsequent 12 training sessions of the rehabilitation program. Endurance training on a cycle ergometer was performed throughout the program. Results Symptom burden in the COPD Assessment test was reduced by 6 points (40%). Lower limb strength improved by 95.3 Nm (521%) and 88.4 Nm (433%) for the knee extensors and by 33.8 Nm (95%) and 56 Nm (184%) for the knee flexors, respectively. Functional exercise capacity improved by 44 m (11%) in the 6-Minute Walk Test and 14 repetitions (108%) in the 1-minute sit-to stand test. The patient did not experience any adverse events related to the exercise training. Conclusion Clinically relevant changes were observed in both strength-related functional and self-reported outcomes. The achievements translated well into daily living and enabled functioning according to the patients’ desires. LL-BFRT was reported to be well tolerated and implementable into an outpatient pulmonary rehabilitation program. Impact The description of this case encourages the systematic investigation of LL-BFRT in COPD. LL-BFRT has the potential to increase benefits as well as tolerability of strength training in pulmonary rehabilitation. Consideration of the physiological changes achieved through LL-BFRT highlights potential in targeting peripheral muscle dysfunction in COPD.


2006 ◽  
Vol 36 (9) ◽  
pp. 761-766 ◽  
Author(s):  
Usha Kuruganti ◽  
Philip Parker ◽  
Jeremy Rickards ◽  
Maureen Tingley

2022 ◽  
Vol 12 ◽  
Author(s):  
Lurdes Ávila-Carvalho ◽  
Filipe Conceição ◽  
Juan A. Escobar-Álvarez ◽  
Beatriz Gondra ◽  
Isaura Leite ◽  
...  

Jumping ability is considered a determinant of performance success. It is identified as one of the predictors and talent identification in many sports and dance. This study aimed to investigate the effect of 16 weeks of lower-limb strength training on the jumping performance of ballet dancers. A total of 24 participants from the same dance school were randomly selected in the control group [CG; n = 10; aged 13.00 (1.49) years; 43.09 (9.48) kg and 1.53 (0.11) m] and the intervention group [IG; n = 14; aged 12.43 (1.45) years; 38.21 (4.38) kg and 1.51 (0.07) m], evaluated before and after the applied strength training program mainly using the body weight of each participant. Jump performance was assessed using MyJump2, a scientifically validated mobile phone app. Intergroup and intragroup comparisons were assessed, and the magnitude of change was calculated using the effect size (ES). While CG significantly decreased the relative power over time (p < 0.001, ES = −0.29: small), results from the intragroup comparisons suggest that IG significantly increased the countermovement jump (CMJ) height (p < 0.001, ES = 1.21: large), the relative force (p < 0.001, ES = 0.86: moderate), maximal velocity (p < 0.001, ES = 1.15: moderate), and relative power (p < 0.001, ES = 1.37: large). We concluded that a 16-week strength training program of lower limbs is an effective way to improve CMJ height in young dancers. Supplementary strength training appears to be the determinant for the improvement of the jumping performance of ballet dancers.


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