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Aim. To determine and compare short and long-term effects of mobilization with movement and eccentric overload to hand pain and function in the treatment of lateral epicondylitis. Problem of research & hypothesis. The eccentric overload exercises are one of the best methods in tendinopathy treatment. Mobilization with movement is largely used as an effective treatment method for lateral epicondylitis. Only the short-term effects of these methods in lateral epicondylitis are often evaluated, but no studies were found to use these methods in combination and to evaluate their long-term effects. Methods. The study included individuals (n=30) aged 30–54 years who had been diagnosed with lateral epicondylitis. Subjects were tested by assessing their perceived pain using the visual analogue scale (VAS); handgrip strength was assessed by a dynamometer. The QuickDASH questionnaire was used to assess hand function and perceived disability. Subjects were randomly divided into three groups: mobilization with movement group (n=10), eccentric overload group (n=10), and combined group (combined mobilization with movement and eccentric overload exercises) (n=10). All subjects got 10 physiotherapy procedures, short-term effect evaluated after 10 procedures of physiotherapy, long-term effect evaluated after 2, 6 and 12 weeks post treatment course. Results. Study results revealed that all treatment methods had a significant (p

Proton magnetic resonance spectroscopy (

Background Normal aging is associated with progressive functional loss in many cognitive domains, including working memory, attention (van Raalten et al., 2008) and executive functions (Nyberg et al., 2008), responsible for the control of behavioral activities (Miller & Cohen, 2001). Research aim was to evaluate postural control and executive function during dual tasking in physically active and inactive old adults. Methods Participants were 42 older healthy human males and females (Mean age: 70.17±6.08 years). Posturography method with a single piezoelectric force plate was used to measure postural sway activity. For the evaluation of cognitive functions, we used Word Memory task with ten audio-recorded words (Lithuanian nouns) in each trial, and the Mathematical Processing Task, where negative or positive one-digit integer-numbers (10 in total) were presented in each trial at 2-second intervals. Physical activity of participants was evaluated according to WHO recommendations. Results The study showed that there was a strong correlation between physically active time spent and balance behavior. The balance of physically active older people was statistically significantly more stable when they performed cognitive tasks than that of those who were physically inactive. Dual-task interferences on postural sway were evident in both Word Memory task and the Mathematical Processing Task conditions. Dual-task effect on Mathematical Processing Task and Word Memory task was not statistically different. Discussion Taken together, we suggest that physical activity improves proprioceptive control which also improves balance control. In dual tasking, more attention is required in cognitive tasking, so better proprioception allows for better balance control with fewer attention resources. However, it is also evident that participants can reduce sway activity and increase balance stability by increasing attentional control.

The effects of acute strength training on balance control were studied in healthy older human men (age-range 60-77y). Participants performed the Tandem Romberg Stance while completing an attention demanding cognitive task (Mathematical Counting) before and after a single acute strength training session applied to the lower limb musculature (experimental group; n=19) or no intervention (control group; n=18). Balance stability and the automaticity of balance control were estimated through the calculation of the center-of-pressure (CoP) velocity (Vcop) and the statistical regularity (wavelet entropy) of the CoP trajectory (WEcop), respectively. Training included 3 sets of 3 repetitions of barbell squats using Smith Machine, ranging from 90% of one repetition maximum (1RM) to 100% 1RM with 3 min rest between repetitions and 5 min rest between sets. Vcop and WEcop decreased after training (all time main effects, p ≤ 0.028) but group time interactions were not significant (all, p ≥ 0.056). Exploratory analyses revealed that participants in the experimental group showed a significant decrease of Vcop and WEcop in the mediolateral (ML) directions from pre to post [ML Vcop: 15.4%; Bonferroni-corrected p = 0.048); ML WEcop: 10.5%; Bonferroni-corrected p = 0.016]. A trend towards a decrease in Vcop and WEcop was also observed in controls, with more prominent gains in the anteroposterior than in the ML direction (Bonferroni-corrected p > 0.2). Overall, findings suggest that acute strength training may improve attentional control of balance along the narrow dimension of the support. Further studies are warranted to examine the specific mechanisms underlying these findings. ispartof: Neuroscience Letters vol:749 pages:135718-135718 ispartof: location:Ireland status: Published online

The paper addresses relations between the characteristics of body composition in international sprint swimmers and sprint performance. The research included 82 swimmers of international level (N = 46 male and N = 36 female athletes) from 8 countries. We measured body composition using multifrequency bioelectrical impedance methods with &ldquo, InBody 720&rdquo, device. In the case of male swimmers, it was established that the most important statistically significant correlation with sprint performance is seen in variables, which define the quantitative relationship between their fat and muscle with the contractile potential of the body (Protein-Fat Index, r = 0.392, p = 0.007, Index of Body Composition, r = 0.392, p = 0.007, Percent of Skeletal Muscle Mass, r = 0.392, p = 0.016). In the case of female athletes, statistically significant relations with sprint performance were established for variables that define the absolute and relative amount of a contractile component in the body, but also with the variables that define the structure of body fat characteristics (Percent of Skeletal Muscle Mass, r = 0.732, p = 0.000, Free Fat Mass, r = 0.702, p = 0.000, Fat Mass Index, r = &minus, 0.642, p = 0.000, Percent of Body Fat, r = &minus, 0.621, p = 0.000). Using Multiple Regression Analysis, we managed to predict swimming performance of sprint swimmers with the help of body composition variables, where the models defined explained 35.1 and 75.1% of the mutual variability of performance, for male and female swimmers, respectively. This data clearly demonstrate the importance of body composition control in sprint swimmers as a valuable method for monitoring the efficiency of body adaptation to training process in order to optimize competitive performance.

This study aimed to identify the game-related statistics that discriminated between Euroleague basketball players and European basketball players playing in the NBA, when competing in the same event (EuroBasket 2015). There was a total of 78 matches played by 24 teams in two groups of analysis: NBA, participants in the European Championship who played in the NBA season of 2014-2015 (n = 26); Euroleague, participants in the European Championship who played in the Euroleague season of 2014-2015 (n = 82). The players’ performance variables were normalized to the time they spent on the court. To identify which variables best discriminated between the NBA and the Euroleague performance profiles, a descriptive discriminant analysis was conducted. Structure coefficients (SC) from the matrix greater than |0.30| were interpreted as meaningful contributors to discriminating between the groups. The results revealed a significant function (p = 0.008, canonical correlation of 0.51, Λ = 0.74, reclassification = 84.2%) and substantial performance differences in game-related statistics much related to the influence of body size (body height and mass), such as two-point field goals made (SC = 0.42) and missed (SC = 0.40), free-throws made (SC = 0.55), defensive rebounds (SC = 0.62), blocks (SC = 0.48) and suffered fouls (SC = 0.34). No differences were found at the level of game-related statistics indirectly related to perception, such as assists, turnovers or steals. Also, the greater body size in NBA players was likely related to higher variability in performance, thus, being an important topic for coaches and recruiters to analyse.

Age-related changes in postural control are attributed to visual, vestibular and proprioceptive dysfunctions, muscle weakness, and reduced availability of neural resources required for efficient balance control. Concurrent performance of complex cognitive tasks while standing or walking is expected to increase balance instability due to under-recruitment of brain resources and insufficient allocation of attention to the postural task. Both balance instability and attentional control of movements can, nonetheless, be determined from the center of pressure (CoP) measurements by examining the effects of dual-task on the amount of sway activity (as measured by CoP velocity − Vcop) and the statistical regularity of the CoP trajectory (the wavelet entropy of the signal − WEcop). The abovementioned characteristics were examined in the present study in a group of 13 healthy older adults. The task involved maintaining Romberg stance for 25 s with or without performing an attention demanding cognitive tasks (word memorization or mathematical counting). A linear mixed-model study was designed to analyze the extent to which sway activity can predict sway regularity. Findings from the present study showed that, on average, Vcop and WEcop were positively correlated (p = 0.014), suggesting that older individuals who exhibited greater amounts of sway (i.e., higher Vcop) also increased sway irregularity of the posturogram – as evidenced by a higher level of wavelet entropy of the CoP trajectory. Nevertheless, results of the linear mixed model showed that significant positive associations between Vcop and WEcop were found only in dual task (R ≥ 0.67, p ≤ 0.012). Furthermore, dual-task effects (% change in performance) on both sway characteristics were not significant (p > 0.1), suggesting that none of the attention demanding cognitive tasks used in the present study was sufficient to divert a critical amount of attentional resources from the postural task. Finally, performance of the mathematical counting (but not the word memorization) task was deteriorated from sitting to standing, however this effect was marginal (p = 0.075). Taken together, we proposed that while dual task could hinder balance control, postural stability may still be maintained by allocating more attentional resources to the postural task and reducing automatized control. ispartof: Neuroscience Letters vol:666 issue:1 pages:153-157 ispartof: location:Ireland status: published

Increased production of reactive oxygen/nitrogen species (ROS) and impaired cellular Ca2+ handling are implicated in the prolonged low-frequency force depression (PLFFD) observed in skeletal muscle...

Summary Aim The aim of this study was to compare the effects of a 4-week combined sloped training program with a standard flat training program performed by basketball players. Methods A total of 31 male elite youth basketball players were randomly allocated into an experimental (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg) and control training group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg). A pre- to post-test design was used to explore the effects in performance variables. Results The comparison between groups showed moderate higher values in FLAT training group for standing height jump (differences in groups means: % [90% confidence intervals], −10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE training promoted a small improve in anaerobic-alactic power (W/kg) (3.4% [−1.2% to 8.1%]). The FLAT group presented small improvements in peak power (W), (−9.2% [−15.0% to −3.0%]) and moderate in relative peak power (W/kg) (−9.8% [−15.3% to −4.0%]). Power results suggested a more efficient movement pattern, probably due to a better propulsive phase supported by an improved ability to produce equivalent levels of force in a shorter period of time. Despite the identified benefits of combined uphill/downhill/flat training method, results suggest that young non-familiarize players need a progressive reduction of training load to optimize performance. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks to enhance players’ performance.

The dominance of fatigue or post-activation potentiation (PAP) depends on the type, intensity, and duration of exercise and duration of the recovery before contractility is tested. Although the decrease in PAP magnitude with decreased exercise intensity is well documented (Vandervoort et al., 1983; Behm et al., 2004), it is not clear how PAP and fatigue influences the contractile properties of skeletal muscle when exercise is of different intensity but with the same amount of work performed. Thus it is important to understand the manifestation of PAP and fatigue of skeletal muscle after continuous maximal and submaximal contractions but with the same amount of work performed. Eight healthy untrained men (age 23—27 years, mass 83.5 ± 5.4 kg) performed maximal sustained isometric knee extension for 30 s (MVC-30 s) and on the other occasion the same subject performed sustained isometric knee extension for 60 s at 50% of maximal (50% MVC-60 s). We assumed that the amount of performed work was the same during both MVC-30 s and 50% MVC-60 s exercises. The experimental order was randomized. The contractile properties of quadriceps muscle evoked by electrical stimulation at 1 Hz (P 1), 10 Hz (P 10), 20 Hz (P 20), and 50 Hz (P 50) as well as contraction time (CT) and relaxation time (RT) of single twitch (P 1) and EMGrms of v. lateralis muscle were recorded before and immediately after the exercises (0 min) and 1, 2, and 3 min following the exercises. A significantly greater potentiation (p < 0.05) of P1 was observed after 30-s MVC (MVC-30 s) compared with the 60-s MVC (50% MVC-60 s) immediately after exercise and at 1 min of recovery. No changes in P 1 contraction time (CT) were observed during 3 min recovery period, however half relaxation of P 1 (½ RT) was more prolonged (p < 0.05) immediately after 50% MVC-60 s exercises. Moreover, immediately and 1 min post exercise the P 10 force after MVC-30 s exercise was higher (p < 0.05) compared to 50% MVC-60 s exercise. No differences between MVC-30 s and 50% MVC-60 s exercises were observed at high stimulation frequencies, maximal voluntary contraction force (MVC) as well as for EMGrms values during 3 min recovery period. The main finding of the present study was that PAP was observed after both maximal and submaximal intensity exercises when the same amount of work was performed. The more intensively exercise is performed, the more PAP offsets fatigue straight after exercise (maximal intensity); while after submaximal exercise PAP becomes more evident only during the recovery period.Keywords: skeletal muscle, isometric exercise, maximum voluntary contraction, recovery.

Kūno rengybos specialistai dažnai taiko 10 serijų metodiką (viena raumenų grupė treniruojama tiktai kartą per savaitę atliekant vieną pratimą 10 serijų po 10 kartojimų), tačiau šios metodikos veiksmingumas moksliniais eksperimentais mažai pagrįstas. Taigi tyrimo tikslas — nustatyti keturgalvio šlaunies raumens storio ir kojų raumenų jėgos pokytį po septynių savaičių trukmės pratybų, atliktų taikant skirtingas jėgos lavinimo metodikas. Buvo kelta hipotezė, kad dažni mažos apimties jėgos ugdymo krūviai yra veiksmingesni nei reti didelės apimties. Pastarieji, būdami ne tokie intensyvūs, mažiau aktyvuoja nervinius ir hormoninius mechanizmus, nuo kurių ypač priklauso raumenų jėgos ir masės didėjimas. Buvo tiriama 14 fi ziškai aktyvių vyrų, kurių amžius — 23,3 ± 5,2 m., ūgis — 181,7 ± 5,1 cm, svoris — 77,7 ± 11,1 kg. Prieš eksperimentą tiriamieji treniruokliu atliko spaudimo kojomis testą, po kurio pagal gautus rezultatus buvo su-skirstyti į dvi grupes: pirmą eksperimentinę (E 1 — atliko dažnus, mažos apimties krūvius) ir antrą eksperimentinę (E 2 — atliko retus didelės apimties krūvius). Eksperimentas truko 7 savaites. Kiekvieną savaitę tiriamieji turėjo po trejas pratybas. Abi eksperimentinės grupės vienodai treniravo visus kūno, išskyrus kojų raumenis. E 1 tiriamieji treniruokliu spaudė svorį kojomis 3 kartus per savaitę po 3, 3 ir 4 serijas po 10 kartojimų. E 2 tiriamieji spaudė svorį kojomis vieną kartą per savaitę 10 serijų po 10 kartojimų. Matuoti rodikliai prieš eksperimentą ir po jo: keturgalvio šlaunies raumens storis (ultragarsu), izometrinė maksimalioji valinga ir 100 Hz elektrostimuliacijos sukelta jėga, per kelio sąnarį esant 70º kampui (0º — koja visiškai ištiesta), izokinetinė koncentrinė jėga — 30º / s ir 300º / s greičiu, maksimalioji kojų raumenų jėga — spaudžiant svorį treniruokliu, kūno svoris, riebalų procentas, apskaičiuotas kūno masės indeksas. Po septynių savaičių jėgos krūvių E 1 grupės tiriamųjų keturgalvio šlaunies raumens storis padidėjo 10,6 ± 9,5% (p < 0,05), E 2 — 12,6 ± 11,3% (p < 0,05) (p > 0,05, lyginant E 1 ir E 2 rodiklius). Eksperimento metu labiausiai padidėjo maksimalioji kojų raumenų jėga spaudžiant svorį treniruokliu: 17,7 ± 11,2% (p < 0,05) E 1 ir 19,2 ± 12,3% (p < 0,05) E 2 grupėje (p > 0,05, lyginant E 1 ir E 2 rodiklius). Tuo tarpu izometrinė maksimalioji valinga ir 100 Hz elektrostimuliacijos sukelta jėga bei izokinetinės koncentrinės jėgos momentas statistiškai reikšmingai nepasikeitė ir nepriklausė nuo taikytos krūvių išdėstymo strategijos. Tyrimo rezultatai parodė, kad motorinės sistemos adaptacija yra labai specifi nė. Reti didelės apimties ir dažni mažos apimties septynių savaičių trukmės raumenų jėgos lavinimo krūviai labai padidino keturgalvio šlaunies raumens storį ir maksimaliąją kojų raumenų jėgą spaudžiant svorį treniruokliu, tačiau mažai keitė izometrinę bei izokinetinę jėgą. Taikant skirtingą jėgos ugdymo metodiką, aktyvuojami ne tie patys adaptacijos mechanizmai, tačiau buvo sukeltas labai panašus adaptacijos efektas.Raktažodžiai: 10 serijų metodas, keturgalvio šlaunies raumens storis, izometrinė jėga, izokinetinė jėga, elektrostimuliacija.

Research background. Stretching is believed to enhance performance, reduce injury, and be an effective means of developing flexibility and alleviating muscular soreness (Shellock, Prentice, 1985; Brandy et al., 1997). A review of the current literature shows that the results of many studies conflict with others; some report that static stretching diminishes vertical jum (VJ) performance (Cornwell et al., 2001; McNeal, Sands, 2003; Wallmann et al., 2005), whereas others report that static stretching has no effect at all on VJ (Church et al., 2001; Power et al., 2004; Unick et al., 2005). Research aim, was to examine the effects of different durations of stretching on performance and to find the stretching durations that affect the performance negatively or positively. Research methods. The subjects of the study were 27 rhythmic gymnasts with the mean age of 10.00 ± 1.2 years. The subjects as a whole group participated in two different stretching programs on nonconsecutive days to eliminate the effect of individual differences on the performance. On the first day, athletes were asked to warm up by 5 minute jogging after the pretest was administered. The posttest measured the vertical jump performance after athletes stayed inactive for 20 minutes. They rested for a day and on the third day, their performance was measured again. After the 5 minute warm-up period, 10 repetitions of 15 seconds static stretching exercises for hip flexor, hamstring and gastrocnemius muscle groups were followed by the posttest. Moreover, on the fifth day 30-second exercises were repeated five times on the same type of muscles. The participants in this investigation were tested in individual vertical jump performances following warm-up only, warm-up plus 15 seconds static stretching, and warm-up plus 30 seconds. Research results. Results of a one-way repeated-measures ANOVA indicated a nonsignificant difference for vertical jump performance (F = 2.052; p > 0.05). Discussion and conclusions. Stretching exercises are referred in rhythmic gymnastics more intensively than other sports. Relevant literature displays fewer stretching repetitions and durations. These durations and repetitions may not be realistic and practical for rhythmic gymnasts. Therefore, the durations and repetitions utilized in this study are considered more appropriate for rhythmic gymnastics trainings. Rhythmic gymnasts may make use of duration and repetitions determined in this study that will not affect their performance. Keywords: anaerobic power, gymnastics, exercise.

Research background and hypothesis. Anterior cruciate ligament (ACL) of the knee joint is often quite a fragile structure of the knee. After the rupture of ACL neuromuscular control worsens and sensorimotor system breaks down (Risberg et al., 2007), muscle activation is poor and muscle strength decreases (Croce, Miller, 2006). Some authors have reported greater strength loss in quadriceps femoris than in hamstring femoris muscle (Busch- Joseph et al., 2001; Neeter et al., 2006), therefore we hypothesized that strength loss in knee extensors may affect hamstring/quadriceps torque (H:Q) ratio. Research aim of this study was to investigate knee extensors and fl exors isometric and dynamic torque and H:Q ratio alterations before ACL surgery and after rehabilitation. Research methods. Ten volunteers with ACL ruptured knee where tested before surgery and after rehabilitation. Isokinetic dynamometer was used for this testing. Maximal isometric torque was performed during fl exion and extension at 90°, 60º knee angles. Dynamic torque was performed at 30, 180, 300º/s angular velocities. Research results. Results of this study show that after rehabilitation isometric and dynamic torque of the involved leg decreased. Isometric fl exion and extension torque of the uninjured leg was greater than that of the injured leg, but after rehabilitation the extension torque of the injured leg was lower than that before surgery. Discussion and conclusions. Before ACL surgery and after rehabilitation quadriceps femoris muscle torque of the uninjured leg was more affected than hamstring femoris muscle torque. After rehabilitation H:Q ratio of the injured leg was not dependent on angular velocity and knee joint angle. Keywords: maximal voluntary torque, muscle balance, muscle contraction.

Purpose Fitness level modulates the physiological responses to exercise for a variety of indices. While intense bouts of exercise have been demonstrated to increase tear osmolarity (Tosm), it is not known if fitness level can affect the Tosm response to acute exercise. This study aims to compare the effect of a maximal incremental test on Tosm between trained and untrained military helicopter pilots. Methods Nineteen military helicopter pilots (ten trained and nine untrained) performed a maximal incremental test on a treadmill. A tear sample was collected before and after physical effort to determine the exercise-induced changes on Tosm. Results The Bayesian statistical analysis demonstrated that Tosm significantly increased from 303.72 ± 6.76 to 310.56 ± 8.80 mmol/L after performance of a maximal incremental test. However, while the untrained group showed an acute Tosm rise (12.33 mmol/L of increment), the trained group experienced a stable Tosm physical effort (1.45 mmol/L). There was a significant positive linear association between fat indices and Tosm changes (correlation coefficients [r] range: 0.77–0.89), whereas the Tosm changes displayed a negative relationship with the cardiorespiratory capacity (VO2 max; r = −0.75) and performance parameters (r = −0.75 for velocity, and r = −0.67 for time to exhaustion). Conclusions The findings from this study provide evidence that fitness level is a major determinant of Tosm response to maximal incremental physical effort, showing a fairly linear association with several indices related to fitness level. High fitness level seems to be beneficial to avoid Tosm changes as consequence of intense exercise.

The purpose of the present study was to investigate the relationships between general coordination, sport-specifi c coordination, and sport-specifi c fi tness of 8- to 17-year-old male basketball players. 312 males with training experience ranging from one year in the 8-year-old cohort up to 10 years for the 17-yearolds performed basketball-specifi c fi tness (20 m sprint, Illinois, countermovement jump), general coordination (20 m run with three obstacles), semi-basketball-specifi c coordination (20 m sprint dribbling two balls, countermovement jump with arm swing) and basketball-specifi c coordination (Illinois ball dribbling) tests. There were moderate to large correlations between the results of both general and basketball- specifi c coordination with the results of most basketball-specifi c coordination tests in all age groups. Correlations between general and basketball-specifi c coordination were large in four age groups (11–14 yr., r = .52 to r = .76), moderate in fi ve groups (8–10, 15 & 16 yr., r = .37 to r = .46), while not signifi cant in the 17-year-olds. These results suggest that the importance of general coordination for sport-specifi c skills improvements during a sports-specifi c skill acquisition phase, remains high at the skill refi nement phase, and decreases when sport-specifi c skills have been mastered to near-perfection.

We studied the relation between two common force modifications in skeletal muscle: the prolonged force depression induced by unaccustomed eccentric contractions, and the residual force depression (rFD) observed immediately after active shortening. We hypothesized that rFD originates from distortion within the sarcomeres and the extent of rFD: 1) correlates to the force and work performed during the shortening steps, which depend on sarcomeric integrity; and 2) is increased by sarcomeric disorganization induced by eccentric contractions. Nine healthy untrained men (mean age 26 yr) participated in the study. rFD was studied in electrically stimulated knee extensor muscles. rFD was defined as the reduction in isometric torque after active shortening compared with the torque in a purely isometric contraction. Eccentric contractions were performed as 50 repeated drop jumps with active deceleration to 90° knee angle, immediately followed by a maximal upward jump. rFD was assessed before and 5 min to 72 h after drop jumps. The series of drop jumps caused a prolonged force depression, which was about two times larger at 20-Hz than at 50-Hz stimulation. There was a significant correlation between increasing rFD and increasing mechanical work performed during active shortening both before and after drop jumps. In addition, a given rFD was obtained at a markedly lower mechanical work after drop jumps. In conclusion, the extent of rFD correlates to the mechanical work performed during active shortening. A series of eccentric contractions causes a prolonged reduction of isometric force. In addition, eccentric contractions exaggerate rFD, which further decreases muscle performance during dynamic contractions.

To compare the concomitant treatment of articular cartilage damage in the medial femoral condyle with osteochondral autologous transplantation (OAT), microfracture, or debridement procedures at the time of anterior cruciate ligament (ACL) reconstruction.Between 2006 and 2009, 102 patients with a mean age of 34.1 years and with an ACL rupture and articular cartilage damage in the medial femoral condyle of the knee were randomized to undergo OAT, microfractures, or debridement at the time of ACL reconstruction. A matched control group was included, comprising 34 patients with intact articular cartilage at the time of ACL reconstruction. There were 34 patients in the OAT-ACL group, 34 in the microfracture (MF)-ACL group, 34 in the debridement (D)-ACL group, and 34 in the control group with intact articular cartilage (IAC-ACL group). The mean time from ACL injury to operation was 19.32 ± 3.43 months, and the mean follow-up was 36.1 months (range, 34 to 37 months). Patients were evaluated with the International Knee Documentation Committee (IKDC) score, Tegner activity score, and clinical assessment.Of 102 patients, 97 (95%) were available for the final follow-up. According to the subjective IKDC score, all 4 groups fared significantly better at the 3-year follow-up than preoperatively (P.005). The OAT-ACL group's IKDC subjective knee evaluation was significantly better than that of the MF-ACL group (P = .024) and D-ACL group (P = .018). However, the IKDC subjective score of the IAC-ACL group was significantly better than the OAT-ACL group's IKDC evaluation (P = .043). There was no significant difference between the MF-ACL and D-ACL groups' IKDC subjective scores (P = .058). Evaluation of manual pivot-shift knee laxity according to the IKDC knee examination form showed similar findings for the 4 groups immediately postoperatively and at 3-year follow-up, and the findings were rated as normal or nearly normal (IKDC grade A or B) in 29 of 33 patients (88%) in the OAT-ACL group, 28 of 32 patients (88%) in the MF-ACL group, 27 of 32 patients (84%) in the D-ACL group, and 31 of 34 patients (91%) in the IAC-ACL group.Our study shows that intact articular cartilage during ACL reconstruction yields more favorable IKDC subjective scores compared with any other articular cartilage surgery type. However, if an articular defect is present, the subjective IKDC scores are significantly better for OAT versus microfracture or debridement after a mean period of 3 years. Anterior knee stability results were not significantly affected by the different articular cartilage treatment methods.Level II, prospective comparative study.

To evaluate possible differences in knee extension and flexion torque variability in the anterior cruciate ligament-deficient (ACLD) leg and their dependence on muscle length and visual feedback (VF). Although a knee extension torque deficit is found in the ACLD leg, there is no evidence that variability in submaximal isometric knee extension and flexion torque is affected in the ACLD leg or that it depends on VF.All tests were performed using 13 untrained men with unilateral ACL rupture. Isometric knee extension torques at 90(o) and 120(o) and knee flexion torques at 90(o), 120(o) and 140(o) were evaluated in healthy and ACLD legs. Isometric torque variability at 20% of maximal force was evaluated with or without VF. The coefficients of variation (CV) and permutation entropies (PE) were used to calculate submaximal isometric torque variability.Healthy legs had significantly greater isometric torques at 90(o) and 120(o) knee angles during knee extension compared with ACLD legs. There were no differences between healthy and ACLD legs in torque variability in knee extension and flexion with or without VF. The PE of knee extension torque at knee angles of 90(o) and 120(o) was significantly (P0.05) greater in healthy legs.The effect of ACL deficiency on variability (CV) in submaximal isometric knee extension and flexion torque was not significant. However, PE of knee extension submaximal torque was significantly greater in the healthy leg than in the ACLD leg. When estimating ACL deficit, it is important to measure not only isometric maximal torque but also torque variability and complexity using nonlinear tool during submaximal isometric tasks.III.

Aim: Unaccustomed physical exercise with a large eccentric component is accompanied by muscle damage and impaired contractile function, especially at low stimulation frequencies. A repeated bout of eccentric exercise results in less damage and improved recovery of contractile function. Here we test the hypotheses that (1) a prior stretch–shortening cycle (SSC) exercise protects against impaired muscle function during a subsequent bout of SSC exercise and (2) the protection during exercise is transient and becomes less effective as the exercise progresses. Methods: Healthy untrained men (n = 7) performed SSC exercise consisting of 100 maximal drop jumps at 30 s intervals. The same exercise was repeated 4 weeks later. Peak quadriceps muscle force evoked by electrical stimulation at 15 (P15) and 50 (P50) Hz was measured before exercise, after 10, 25, 50 and 100 jumps as well as 1 and 24 h after exercise. Results: P15 and P50 were higher during the initial phase of the repeated bout compared with the first exercise bout, but there was no difference between the bouts at the end of the exercise periods. P15 and P50 were again larger 24 h after the repeated bout. The P15/P50 ratio during exercise was not different between the two bouts, but it was higher after the repeated bout. Conclusion: A prior bout of SSC exercise temporarily protects against impaired contractile function during a repeated exercise bout. The protection can again be seen after exercise, but the underlying mechanism then seems to be different.

Previous studies have demonstrated that an exercise bout repeated prior to full recovery, within 2-6 days, does not impair muscle function to a greater extent and does not affect the repair process. The aim of this study was to examine whether repeated exercise performed 60 minutes after the first one exacerbates muscle fatigue and damage. Ten healthy, physically active males (21.1 +/- 1.4 years, 75.2 +/- 4.1 kg, 178.7 +/- 4.5 cm) performed 2 bouts of 50 continuous maximal intensity jumps with a 60-minute rest period. Peak quadriceps muscle force evoked by electrical stimulation at 15 (P15) and 50 (P50) Hz and maximal voluntary contraction force (MVCF) were measured 2, 30, and 60 minutes after bout 1 and bout 2. The results demonstrated a significant decrease in P15, P50, and MVCF during bout 1 (p < 0.05). The force did not recover within 60 minutes after exercising. After the second bout, the MVCF and P50 decreased to similar extent both immediately after and 30-60 minutes after the first one despite the fact that bout 2 was repeated with the voluntary and involuntary force still depressed. It was concluded that within 60 minutes repeated jumping exercise does not exacerbate muscle fatigue and muscle damage. From the coach's point of view it is of significance that the neuromuscular system appears to be well protected from frequently repeated muscle damaging exercise.

Immediately after sustained maximum voluntary contractions for 60 s, greater quadriceps muscle fatigue and, especially, low frequency fatigue is observed. The results of our study have shown that immediately after the exercise there was a significant (P0.05) decrease in muscle force induced by low (20 Hz) and high (50 Hz) stimulation frequencies and maximum voluntary contractions (it is not muscle length-dependent) and it did not recover to its initial (pre-exercise) level 15 min after the end of exercise. These observations suggest the observed low frequency fatigue may consist of 2 phases: an early, rapid recovery phase (to 3 min), likely related to muscle potentiation and metabolite build-up, and a slow recovery phase, which is not dependent on metabolite levels, but is especially dependent on muscle mechanical damage. There is an increase in low frequency fatigue during a slow recovery phase and it is more pronounced when low frequency fatigue is registered at short muscle length.

The aim of the study was to investigate the manifestation of potentiation and fatigue as well as the coexistence of these phenomena at different muscle lengths during a 24-hour period after a sprint cycling for 30 s. Material and methods. Twelve healthy untrained men (mean age 23.6±1.7 years) took part in the experiment. The contractility of quadriceps muscle was studied before (Initial) and 2, 5, 30, 60 min and 24 h after exercise via the electrically evoked contractions at 1, 15, 50 Hz and maximal voluntary contractions at short and long muscle length. Results. 1) In early, fast-recovery phase (within the first 5 min), muscle force evoked by electrical stimulation of 1, 15, 50 Hz was restored at short muscle length, conversely at long length (Initial vs. 5 min: 15 Hz and 50 Hz, both P&lt, 0.05), whereas maximal voluntary contraction force was still suppressed at both muscle lengths, 2) in the second phase (from 5 min to 30–60 min), muscle force decreased at low- and high-frequency stimulations and was more expressed at low-frequency stimulation and at short muscle length than that at long length, but the maximum voluntary contraction force recovered to initial, 3) in long-lasting phase (within 24 hours), 15 Hz force was still suppressed at both muscle lengths. Conclusion. A bimodal recovery of contractility of the quadriceps following sprint cycling for 30 s is determined by the concomitant complex interaction of mechanisms enhancing (potentiation) and suppressing (fatigue) contractile potential of the muscle.