A four-week minimalist shoe walking intervention influences foot posture and balance in young adults-a randomized controlled trial.

INTRODUCTION: Minimalist shoes (MS) are beneficial for foot health. The foot is a part of the posterior chain. It is suggested that interventions on the plantar foot sole also affect the upper segments of the body. This study aimed to investigate the local and remote effects along the posterior chain of four weeks of MS walking in recreationally active young adults. METHODS: 28 healthy participants (15 female, 13 male; 25.3 ± 5.3 years; 70.2 ± 11.9 kg; 175.0 ± 7.8 cm) were randomly assigned to a control- or intervention group. The intervention group undertook a four-week incremental MS walking program, which included 3,000 steps/day in the first week, increasing to 5,000 steps/day for the remaining three weeks. The control group walked in their preferred shoe (no MS). We assessed the following parameters in a laboratory at baseline [M1], after the four-week intervention [M2], and after a four-week wash-out period [M3]: Foot parameters (i.e., Foot Posture Index-6, Arch Rigidity Index), static single-leg stance balance, foot-, ankle-, and posterior chain range of motion, and muscle strength of the posterior chain. We fitted multiple hierarchically built mixed models to the data. RESULTS: In the MS group, the Foot Posture Index (b = -3.72, t(51) = -6.05, p < .001, [-4.94, 2.51]) and balance (b = -17.96, t(49) = -2.56, p = .01, [-31.54, 4.37]) significantly improved from M1 to M2, but not all other parameters (all p >.05). The improvements remained at M3 (Foot Posture Index: b = -1.71, t(51) = -2.73, p = .009, [-4,94,0.48]; balance: b = -15.97, t(49) = -2.25, p = .03, [-29.72, 2.21]). DISCUSSION: Walking in MS for four weeks might be advantageous for foot health of recreationally active young adults but no chronic remote effects should be expected.

The Evaluation of Asymmetry in Isokinetic and Electromyographic Activity (sEMG) of the Knee Flexor and Extensor Muscles in Football Players after ACL Rupture Reconstruction and in the Athletes following Mild Lower-Limb Injuries.

This study was aimed at evaluating knee stabilizer (quadriceps and hamstring) muscle strength and the medio-lateral symmetry of hamstring fatigue in football players after ACL reconstruction and with mild lower extremity injuries. The study comprised 65 professional football players who were divided into three groups: Group 1 (n = 24; 22.7 ± 3.6 years; 175 ± 4 cm; 77.3 ± 7.6 kg) after ACL reconstruction, Group 2 (n = 21; 20.5 ± 3.7 years; 177 ± 6 cm; 74.3 ± 9.1 kg) with mild lower-limb injuries (grade 1 muscle strains) and Group 3 (n = 20; 23.1 ± 2.8 years; 178 ± 6 cm; 75.8 ± 8.8 kg) without injuries in the past 3 years. The concentric isokinetic test (10 knee flexions and extensions at 60, 180 and 300°/s with a 30 s interval for rest) was performed on both limbs. Fatigue symmetry between the medial and lateral hamstrings was measured with sEMG during 60 s of isometric contractions. In comparison to the other groups, the injured leg demonstrated significantly lower values of peak torque for the quadriceps (G1-G2 = 48%, 38%, 14%; G1-G3 = 49%, 25%, 14%) and hamstring muscles (G1-G2 = 36%, 35%, 18%; G1-G3 = 64%, 28%, 17%) as well as lower values of hamstring muscle work (G1-G2 = 262 J, 157 J; G1-G3 = 219 J, 179 J) and power (G1-G2 = 34 W; 11 W; G1-G3 = 29 W, 12 W). No significant differences were noted in strength between Groups 2 and 3. The significantly higher fatigue of the BF compared to the SEM muscle was seen in Group 1 for the involved (mean difference = 0.12) and uninvolved limbs (mean difference = -0.10), but in Group 2, a non-significant trend towards asymmetry was also noted. No asymmetry in hamstring muscle fatigue was determined in Group 3. The results of our study allow us to indicate that active football players who previously met the RTS criteria, had deficits in lower-limb muscle performance 2-3 years after reconstruction, which could lead to ACL re-injury. This observation is potentially of importance because these deficits may not be subjectively reported by such athletes and also may not be visible in regular orthopedic and physiotherapeutic assessment.

The Influence of Self-Myofascial Release on Muscle Flexibility in Long-Distance Runners.

During long-distance running, athletes are exposed to repetitive loads. Myofascial structures are liable to long-term work, which may cause cumulating tension within them. The aim of this study was to evaluate the acute effect of self-myofascial release on muscle flexibility in long-distance runners. The study comprised 62 long-distance, recreationally running participants between the age of 20 and 45 years. The runners were randomly divided into two groups: Group 1 (n = 32), in which subjects applied the self-myofascial release technique between baseline and the second measurement of muscle flexibility, and Group 2 (n = 30), without any intervention. The self-myofascial release technique was performed according to standardized foam rolling. Assessment of muscle flexibility was conducted according to Chaitow's proposal. After application of the self-myofascial release technique, higher values were noted for the measurements of the following muscles: piriformis, tensor fasciae latae muscles and adductor muscles. Within the iliopsoas and rectus femoris muscles, lower values were observed in the second measurement. These changes were statistically significant (p < 0.05) within the majority of muscles. All these outcomes indicate improvement related to larger muscle flexibility and also, an increase in range of motion. In the control group (Group 2), significant improvement was observed only in measurements for the iliopsoas muscles. The single application of self-myofascial release techniques with foam rollers may significantly improve muscle flexibility in long-distance runners. Based on these results, the authors recommend the self-myofascial release technique with foam rollers be incorporated in the daily training routine of long-distance runners, as well as athletes of other sport disciplines.

Reliability of Pelvic Floor Muscle Assessment with Transabdominal Ultrasound in Young Nulliparous Women.

The aim of this study was to assess the reliability of pelvic floor muscles evaluation via transabdominal ultrasonography in young nulliparous women and to present the methodology for quantitative assessment of the ultrasound image of the pelvic floor muscles visible as displacement of the posterior wall of the bladder, caused by action of the pelvic floor muscles. The study comprised 30 young, Caucasian, nulliparous women (age 22-27; 168.6 ± 5.1 cm; 57.1 ± 11.8 kg) without pelvic floor muscle dysfunctions. The intra-rater, test-retest and inter-rater reliability of pelvic floor muscles evaluation was performed using transabdominal ultrasound at rest and during voluntary contraction. The reliability was assessed at three points of the image (at the middle, on the right and left side). The reliability of the three-point measurement of the pelvic floor muscles transabdominal ultrasound is excellent in the case of intra-rater assessments, both at rest (ICC = 0.98-0.99) and during contraction (ICC = 0.97-0.98); moderate at rest (ICC = 0.54-0.62) and poor during contraction (ICC = 0.22-0.50) in the case of test-retest assessment; excellent at rest (ICC = 0.95-0.96), and good during contraction (ICC = 0.81-0.87) in the case of inter-rater assessment. Transabdominal ultrasound is a reliable method of pelvic floor muscle evaluation. The three-points of assessment used in our study allowed for broader and more comprehensive imaging of the pelvic floor muscle, e.g., for quantitative detection contractility imbalances between the left and right side Due to the fact that understanding mechanisms of pelvic floor muscle functioning is crucial in the therapy of pelvic floor dysfunctions, therefore, reliable, valid tests and instruments are important.

The Reliability of Pelvic Floor Muscle Bioelectrical Activity (sEMG) Assessment Using a Multi-Activity Measurement Protocol in Young Women.

The aim of the study was to determine the between-trial and between-day reliability of the Glazer protocol and our multi-activity surface electromyography (sEMG) measurement protocol for pelvic floor muscle (PFM) evaluation. The bioelectrical activity of PFM was collected using an endovaginal electrode in 30 young, Caucasian, nulliparous women (age 22-27, 168.6 ± 5.1 cm, 57.1 ± 11.8 kg). The between-trial and between-day reliability of the original Glazer protocol and the new multi-activity sEMG protocol were assessed during the following phases: pre-baseline rest, phasic (flick) contractions, tonic contractions, endurance contraction, and post-baseline rest. The Glazer protocol was characterized by poor and moderate measurement reliability. The time-domain parameters for the rise and fall of the signal amplitude and median frequency showed poor between-trial and between-day reliability. The mean and peak amplitudes indicated mainly good between-trial and moderate between-days reliability. Our protocol showed moderate to excellent reliability of both time-domain and quantitative parameters of muscle recruitment. In our protocol, the frequency-domain parameters describing muscle fatigue demonstrated much higher reliability than in the case of the Glazer protocol. The most important information obtained in this study was the significant improvement of diagnostic validity in PFM bioelectrical activity evaluation. The higher reliability of our sEMG protocol compared to original Glazer protocol allowed us to suggest that protocol modifications and changes in sEMG signal processing methods were effective in the improvement of PFM assessment quality. The new parameters calculated from the sEMG signal proposed in our sEMG protocol allowed us to obtain additional clinically important information about PFM dysfunctions regarding specific deficits of muscle contraction such as decrease in muscle strength; endurance or coordination related to, e.g., stress urinary incontinence; or pelvic floor muscle imbalance after childbirth.

Standard RTS criteria effectiveness verification using FMS, Y-balance and TJA in footballers following ACL reconstruction and mild lower limb injuries.

The anterior cruciate ligament (ACL) is the most frequently injured knee ligament. In previous studies, it was demonstrated that patients following ACL reconstruction may present motor deficits which may be related to increased risk of injury. The objective of the study was to determine whether players who have passed RTS assessment still have deficits in movement patterns or in neuromuscular control after such a serious injury as ACL rupture and reconstruction,. Sixty-five male football players (age 18-25 years), recruited from regional teams, were divided into three groups: (1) ACL group-subjects after ACL rupture and reconstruction (n = 24); (2) Mild Injury (MI) group-subjects after mild lower limb injuries (n = 21); and (3) Control (C) group-subjects without injuries (n = 20). For all groups, the Y-balance test, Functional Movement Screen (FMS) and Tuck Jump Assessment (TJA) were performed. For the Y-balance test in ACL group for the injured leg, significantly lower values were demonstrated for anterior reach ((ACL) 69.2 ± 5.7% vs. (MI) 74.8 ± 4.5% vs. (C) 74.0 ± 5.6%), at posterior-lateral reach ((ACL) 103.2 ± 6.4% vs. (C) 108.5 ± 6.0%) and composite score ((ACL) 93.9 ± 4.4% vs. (MI) 97.9 ± 4.3%) in comparison to the remaining two groups. In the FMS test, the ACL group had significantly lower composite score (12 ± 4 points) compared to the C group (15 ± 2 points). Also, compared to the remaining groups, subjects following ACL reconstruction demonstrated significantly lower performance in the TJA test related to the following elements: thighs do not reach parallel, thighs not equal side-to-side, foot placement not shoulder width apart, technique declines prior to 10 s and lower extremity valgus at landing. The authors have observed that athletes after ACL reconstruction still have deficits in movement patterns or in neuromuscular control despite passing the RTS and being cleared to perform sports. Creating a set of sufficiently sensitive assessment methods may significantly reduce the potential risk of injury due to the fact that diagnosed and monitored deficits may be treated on an ongoing basis. The authors suggest that individual elements of the Y-balance and TJA tests may be suitable for such specific assessment.

Impact of Short Foot Muscle Exercises on Quality of Movement and Flexibility in Amateur Runners.

The flexibility and proper functioning of all myofascial chains are crucial for athletes, especially for long-distance runners. Due to the continuity of the myofascial structures, restrictions in one part of the body may cause excessive tension in others. The aim of our study was to evaluate the influence of short foot muscle exercises on muscle flexibility and the quality of movement patterns in amateur runners. Eighty long-distance runners, aged 20-45, were randomly divided into two groups: Group 1 (n = 48) and Group 2 (n = 32). Participants in Group 1 performed foot exercises daily for six weeks. Subjects in Group 2 were without any intervention. At baseline and after six weeks, the quality of movement patterns with the Functional Movement Screen and muscle flexibility was evaluated. In Group 1, significantly higher Functional Movement Screen values in individual tasks and in the total score were noted after six weeks. The total score increased from 17 to 18 points (Median (Me) ± half of interquartile range (IQR/2) (Standard Error of Measurement - SEM) 17 ± 1.5 (0.23) at baseline and 18 ± 1.5 (0.24) after six weeks) (p < 0.01), whereas in Group 2, its level remained at 16 points (Me ± IQR/2 (SEM) 16 ± 1.5 (0.31) at baseline and 16 ± 1.25 (0.31) after six weeks). In Group 1, the significant improvement in muscle flexibility was noted (e.g., results for external rotation muscles: (Mean ± SD (SEM) 60.3 ± 0.4 (1.50) at baseline and 62.4 ± 10.3 (1.49) after six weeks) (p = 0.005). In Group 2, significant improvement was observed only for one task in the Active straight leg raise test (p = 0.005 and 0.02). During the measurement of external rotation muscles, a significant decrease in flexibility was observed (Mean ± SD (SEM) 60.1 ± 9.0 (1.60) at baseline and 58.0 ± 8.5 (1.51) after six weeks) (p = 0.001). Plantar short foot muscle exercises may improve muscle flexibility in the upper parts of the body within myofascial chains and influence the quality of fundamental movement patterns. Such exercises may be beneficial for all physically active people and can be performed as part of overall fitness programmes. Moreover, including such exercises in daily training routines of long-distance runners, as well as by athletes in other sport disciplines is also recommended.