RÉSUMÉ
Objective To compare the knee function recovery at different times of returning to sport after anterior cruciate ligament reconstruction(ACLR) among elite athletes using knee isokinetic muscle strength test and various hop test.Methods Forty-one elite athletes(14 males,27 females,mean age 22.6 ± 4.1 years) undergoing ACLR between January 2013 and September 2014 were chosen from the database of the National Institute of Sports Medicine and Shanghai Huashan Hospital.Rehabilitation was performed using the same protocol by professional physiotherapists and trainers,who recorded the time of returning to sport of each athlete.One week prior to the scheduled return,bilateral knee isokinetic muscle strength test(test value:peak torque;angle velocity:60°/s,180°/s;motion:flexion,extension) and four hop tests(single hop for distance,side-to-side hop,up-down hop and 8 hop) were applied with the limb symmetry index(LSI) calculated.The athletes were then grouped by their returntime referring to surgery into the premature group(6～8 months),timely return group(9～12 months) and delayed group(over 12 months).The tests results were recorded and compared among the three groups.Results Fourteen athletes were selected into the premature group,with 19 in the timely group and 8 in the delayed group.The average LSI of 60°/s flexion peak torque of the premature group (87.4％ ± 7.5％) was significantly lower than the timely group(95.8％ ± 6.6％) and the delayed group(96.0％ ± 2.4％) (P＜0.01).Significant differences were observed between the premature group and delayed group regarding the 60° extension peak torque(85.8％ ± 9.4％ and 94.8％ ± 4.8％,P＜0.05),180°/s flexion peak torque(90.7％ ± 8.7％ and 101.4％ ± 6.8％,P＜0.05),and 180°/s extension peak torque (90.6％ ± 5.2％ and 97.8％ ± 5.6％,P＜0.05).The average LSL of the premature group at single hop for distance,side-to-side hop and up-down hop(93.A％ ± 8.5％,84.7％ ± 7.3％ and 112.5％ ± 5.7％) was significantly lower than that of the timely group(95.7％ ± 6.0％,104.2％ ± 4.3％ and 105.3％ ± 7.9％) and the delayed group regarding(98.1％ ± 1.9％,104.7％ ± 4.0％ and 106.3％ ± 7.4％) (P＜0.01 for all).The relative peak torque of 60°/s extension of the premature group(2.48 ± 0.58 Nm/kg) was significantly lower than the delayed group(3.21 ± 0.51 Nm/kg) (P＜0.01).Conclusions For elite athletes,returning to sport within 9 months after ACLR results in insufficient restoration of the knee function.Delayed return to sport doesn't improve the outcomes of hop tests,but can enhance the maximum extension torque peak,which needs further study.
RÉSUMÉ
BACKGROUND: It is well known that eccentric training increases muscle strength and promotes greater neural activation, and therefore has been used in the recovery of knee extensors. The hypothesis of this study was that there would be a strong correlation between knee extensor torque and functional tests. OBJECTIVES: To investigate the relationship between knee extensor peak torque and functional tests of agility (runs) and propulsion (hop for distance) after short-term isokinetic eccentric training. METHODS: Twenty healthy and active male undergraduate students (age 22.5±2.1 years; height 1.72±0.10 m; weight 67.8±9.5 kg; body mass index: 22.5±2.0 kg/m²), with no abnormalities or history of injury of the limbs, performed an isokinetic assessment of the knee extensors and flexors and also functional tests before and after isokinetic training, which consisted of 3 sets of 10 MVECs at 30º/s, with 3 minutes of rest between sets, twice a week for 6 weeks. RESULTS: The eccentric training increased the extensor peak torque (16, 27 and 17 percent; P<0.01) and decreased the H/Q ratio (10, 20 and 13 percent; P<0.01) for the isometric and eccentric modes at 30°/s and 120°/s, respectively. It also decreased the time in two of the five agility tests (carioca and pivot diagonal; P<0.01), and increased the distance in the hop tests, for both dominant and non-dominant limbs (P<0.01). CONCLUSIONS: Although the eccentric training led to an increase in extensor peak torques as well as an improvement in most of the functional tests, the hypothesis that a strong correlation would be observed between peak torques and functional tests was not confirmed. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number 12607000590460.
CONTEXTUALIZAÇÃO: Sabe-se que o treino excêntrico aumenta a força muscular, promovendo uma maior ativação neural e, portanto, tem sido usado na recuperação do torque extensor. A hipótese deste estudo foi a de que possa existir uma forte correlação entre o torque extensor do joelho e os testes funcionais. OBJETIVOS: Correlacionar o torque extensor do joelho com os testes funcionais de agilidade (corridas) e impulsão (saltos em distância) após o treino isocinético excêntrico de curta duração. MÉTODOS: Vinte homens universitários, ativos e saudáveis (22,5±2,1 anos; 1,72±0,10 m; 67,8±9,5 kg; IMC 22,5±2,0 kg/m²), sem reportar anormalidades ou história de lesão no membro inferior, realizaram avaliação isocinética do torque extensor e flexor do joelho e testes funcionais antes e depois do treino isocinético que consistiu em três séries de 10 CEVM a 30º/s, com 3 minutos de repouso entre as séries, realizado duas vezes por semana, durante seis semanas. RESULTADOS: O torque extensor aumentou (16, 27 e 17 por cento; P<0,01), a razão I/Q diminuiu (10, 20 e 13 por cento; p<0,01) para os modos: isométrico e excêntrico a 30°/s e 120°/s, respectivamente; diminuiu o tempo em dois dos cinco testes de corridas (carioca e pivô diagonal; P<0,01) e aumentou a distância nos testes de saltos tanto para o membro dominante quanto para o não dominante (P<0,01). CONCLUSÕES: Embora o treino excêntrico tenha aumentado o torque dos extensores do joelho, bem como melhorado a maioria dos testes funcionais, a hipótese de uma forte correlação entre essas variáveis não se confirmou. Artigo registrado no Australian New Zealand Clinical Trials Registry (ANZCTR) sob o número 12607000590460.