Increasing the resting time between drop jumps lessens delayed-onset muscle soreness and limits the extent of prolonged low-frequency force depression in human knee extensor muscles.

PURPOSE: Unaccustomed eccentric contractions generally result in a long-lasting contractile impairment, referred to as prolonged low-frequency force depression (PLFFD), and delayed-onset muscle soreness (DOMS). We here used repeated drop jumps (DJs) as an eccentric contraction model and studied the effects of increasing the time between DJs from 20 s to 5 min. We hypothesized that both PLFFD and DOMS would be less marked at the longer DJ interval due to the longer time to restore structural elements between DJs. METHODS: Young men (n = 12) randomly performed 50 DJs with either 20-s (DJ-20 s) or 5-min (DJ-5 min) rest between DJs. Voluntary, 20 Hz and 100 Hz electrically stimulated isometric knee extension torques and muscle soreness were monitored before and for 7 days after DJs; serum CK activity was measured to assess muscle fibre protein leakage. In additional experiments, changes in mRNA levels were assessed in muscle biopsies collected before and 1 h after exercise. RESULTS: A marked PLFFD was observed with both protocols and the extent of 20 Hz torque depression was smaller immediately and 1 day after DJ-5 min than after DJ-20 s (p < 0.05), whereas the MVC and 100 Hz torques were similarly decreased with the two protocols. Markedly larger differences between the two protocols were observed for the muscle soreness score, which 1-4 days after exercise was about two times larger with DJ-20 s than with DJ-5 min (p < 0.01). CONCLUSIONS: The larger protective effect of the longer DJ interval against DOMS than against PLFFD indicates that their underlying mechanisms involve different structural elements.

Reliability and validity of DPA-1 testing after anterior cruciate ligament reconstruction.

There is a lack of equipment and methods for the reliable and valid measurements of human neuromuscular control. To overcome this limitation, an analyzer of dynamic parameters (DPA-1) of human hand and leg movements was constructed by Kaunas University of Technology and "Katra" engineers in collaboration with the Lithuanian Academy of Physical Education. The aim of the study was to determine the reliability and validity of the tests performed on the DPA-1 in healthy and injured subjects after the anterior cruciate ligament (ACL) reconstruction surgery. MATERIAL AND METHODS. The men who had undergone a unilateral ACL reconstruction (n=17, on the average 3.8 months [SD, 2.1] after the surgery) and healthy untrained men (n=17) performed the research protocol twice within 24 hours in between. Average reaction time, mean and maximal movement speed, time to reach maximal speed, and movement distance of the right and left feet for the patients and of the dominant foot for the healthy subjects using the DPA-1 as well as the scores of isokinetic muscle strength and self-assessment tests were registered. RESULTS. There was a significantly reduced concentric peak torque on the injured knee compared with the uninjured knee during knee extension, and the mean score of the Lysholm scale for the injured knee was 69.1 (SD, 13.7) (P<0.05, compared between legs). The test-retest reliability for all the DPA-1 tests varied from 0.68 to 0.94 (P<0.05). However, there were no significant differences in most variables measured by the DPA-1 between injured knee, uninjured knee, and control knee. CONCLUSIONS. The results revealed low validity of the DPA-1 tests for the evaluation of patients following ACL surgery, despite the reliability of these tests varied from moderate to very high.

Arthroscopic coracoid transposition for recurrent shoulder anterior instability: an operative technique.

We report a technique of an arthroscopic concomitant Bankart repair with a transfer of the coracoid bone block and conjoint tendons for revision anterior shoulder instability. The operative procedure consists of an arthroscopic transfer of the conjoined tendon with a coracoid and arthroscopic Bankart repair. First, a typical Bankart suture anchor procedure with two suture anchors was performed into the antero-inferior part of the glenoid rim. After, tenodesis of the coraco-biceps tendon was performed in the middle of the subscapularis tendon fixing the coracoid bony fragment into a glenoid socket with a bioabsorbable interference screw. This operative technique is an alternative in the treatment of revision anterior shoulder instability in patients with deficient anterior capsule.

[Impact of intensive and traditional rehabilitation on quadriceps strength after anterior cruciate ligament reconstructive surgery]. / Intensyviosios ir iprastines reabilitacijos poveikis blauzdos tiesiamuju raumenu jegai atlikus priekinio kryzminio raiscio rekonstruojamaja operacija.

UNLABELLED: After knee anterior cruciate ligament reconstructive surgery, the recovery of the former level of physical activity takes from 3 to 12 months. Such a wide range of recovery period of physical activity suggests that rehabilitation in most cases is not optimal. According to the majority of authors, after the surgery, a patient can resume intensive physical activity, when the difference in muscle strength between the operated lower extremity and another extremity is not greater than 10-15%. The aim of this study was to compare the impact of intensive and normal rehabilitations on the recovery of knee extensor muscle strength after the surgery. MATERIAL AND METHODS: A total of 40 patients were enrolled in this study. The subjects were divided into two groups. Both groups were engaged in physical activity. The mean age of patients (16 men and 4 women) in the first group at the time of surgery was 26.4+/-8.1 years, mean height - 179.8+/-8.5 cm, and mean weight - 76.0+/-14.0 kg. An intensive rehabilitation was applied for the first group of the patients studied. The second group consisted of 13 men and 7 women who were engaged in moderate physical activity. Their mean age at the time of surgery was 27.0+/-9.3 years, mean height - 173.2+/-6.2 cm, and mean weight - 71.0+/-9.0 kg. A traditional rehabilitation was applied to this group. Muscle strength was measured in the patients of both groups studied approximately 5.2 months following surgery using the Biodex isokinetic dynamometer. RESULTS: The patients undergoing an intensive rehabilitation achieved higher levels of knee extensor muscle strength than those patients undergoing a traditional rehabilitation program. Applying an aggressive rehabilitation program, knee extensor muscles recover more quickly than using a traditional rehabilitation program. The comparison of intensive and traditional rehabilitation programs applied to the operated and unoperated lower extremities has shown that the indexes of knee extensor muscle strength differed by 11.51-12.74%. Applying a traditional rehabilitation, a 23.68-49.42% difference in knee flexor muscle strength between operated and unoperated extremities was noted. CONCLUSIONS: The effect of intensive rehabilitation aimed at strength recovery of knee extensor muscles after anterior cruciate ligament reconstructive surgery is greater than after ordinary rehabilitation.