Regional differences in the biological variability of plantar pressure as a basis for refining diagnostic gait analysis.

The variability of movement plays a crucial role in shaping individual's gait pattern and could, therefore, potentially serve diagnostic purposes. Nevertheless, existing concepts for the use of variability in diagnosing gait present a challenge due to the lack of adequate benchmarks and methods for comparison. We assessed the individuality of contribution of foot parts that directly mediate the transmission of forces between the foot and the ground in body weight shifting during walking based on 200 pedobarometric measurements corresponding to the analysed foot parts for each of 19 individuals in a homogeneous study group. Our results show a degree of individualisation of the contribution of particular foot parts in the weight-shift high enough to justify the need to consider it in the diagnostic analysis. Furthermore they reveal noticeable, functionally driven differences between plantar areas most apparent between the lowest individuality for the first foot ray and the highest for second one and metatarsus. The diagnostic reference standard in pedobarometry should describe the contribution in the shift of body weight during walking for each area of the foot separately and include information on the intra-individual variation and individualisation of descriptors of the contribution. Such a comprehensive standard has the potential to increase the diagnostic value of pedobarometry through enrichment of the assessment description.

Stressor-Induced Temporal Cortisol Deficiency as a Primary Trigger for Adaptation to Stress.

BACKGROUND: Inconsistencies in measurements of cortisol response to stress have caused disagreements in the direction of the change in cortisol concentrations immediately after the onset of stress. Researchers typically observe increased cortisol levels in response to a stressor, perceiving occasional decreases as a sign of possible disorders. Reports indicate the relative ease of standardizing a physical stressor compared with a mental stressor, and cross-stressor adaptation is observable only in elite athletes. METHODS: We investigated the cortisol response to top-intensity physical exertion by analyzing the course of the cortisol response, the changes in this response resulting from adaptation to intense exercise, and the possible convergence between the cortisol changes and body fat content. We examined 16 male athletes, members of the Polish National Rowing Team, competing in the World Rowing Championships, in top form, of an average training experience of seven years. The measurements were performed before and after the training camp preparatory to the Championships. We performed the measurements before and after the training camp preparatory to the Championships. RESULTS: Before the camp, the athletes consistently reacted to the exertion test with a decrease in cortisol concentration and elevated cortisol levels after rest compared with baseline. After the camp, the post-exertion cortisol decrease as well as the post-rest cortisol elevation was much smaller and less consistent. CONCLUSIONS: The transient decrease in cortisol concentration at the onset of stress thus represents a physiological reaction, and the stress response counteracts the resulting cortisol deficiency to support cortisol availability during stress. Adaptation to stress enhanced this counteracting effect by (1) increasing the baseline cortisol concentration and (2) speeding up the response to its decline. This enhanced effect was boosted by adipose tissue.

Standardized astragalus extract for attenuation of the immunosuppression induced by strenuous physical exercise: randomized controlled trial.

BACKGROUND: This paper aimed to verify how a supplementation of rower's diet with Astragalus Membranaceus Root (AMR) modulated their immune system response to maximal physical exertion. METHODS: The double-blind study included 18 members of the Polish Rowing Team assigned to the supplemented group (n = 10), and the placebo group (n = 8). The participants performed a 2000 m test on a rowing ergometer at the beginning and at the end of the six-week of intensive training camp during which the supplemented group received 500 mg of AMR. Blood samples were obtained prior to, 1 min after completing, and 24 h after the exertion test. The levels of interleukin 2 (IL2), interleukin 4 (IL4), interleukin 10 (IL10), interferon ɤ (IFN-É£), and lactic acid were determined. Subpopulations of T regulatory lymphocytes [CD4+/CD25+/CD127-] (Treg), cytotoxic lymphocytes [CD8+/TCRαß+] (CTL), natural killer cells [CD3-/CD16+/CD56+] (NK), and TCRδγ-positive cells (Tδγ) were determined with flow cytometry. RESULTS: After the camp, the initial NK and Treg levels sustained at the baseline, while Tδγ counts increased relative to the levels in the placebo group. In the supplemented subgroup, a decrease in IL2 level in reaction to maximal exertion clearly deepened while the change in IL-2/IL-10 level induced by the recovery after this exertion clearly increased, relative to the changes in the placebo group. CONCLUSIONS: AMR restored the immunological balance in strenuously trained athlets through a stabilization of NK and Treg cells with a positive trend in Tδγ towards Th1 response during restitution by cytokine IL2 modulation.

Constraints on variation of weight-shifting by foot during walking in adolescents with valgus alignment of hallux.

PURPOSE: Etiology of hallux valgus (HV) remains unclear and effective treatments and prophylaxis for this condition are lacking and conclusions of researches concerning HV are inconsistent. Recognition of the function-structure interrelation in foot at the early stage of valgus alignment of first metatarsophalangeus joint (1stMTPJ) would help explain the etiology of HV. METHODS: The frequency of weight-shifting patterns during walking and the body mass index (BMI) were assessed relative to goniometric measurements of the 1stMTPJ angle in adolescents. Weight-shifting patterns were identified with a plantar pressure analysis, performed with the Gaitline- Maxline Distance method. RESULTS: As the 1stMTPJ angle widened, the frequency distributions of identified weight-shifting patterns became increasingly lopsided, due to the favoring or disfavoring of one pattern at the expense of the other. The two sexes showed opposite trends in the weight-shifting patterns that were favored/disfavored, relative to participants with a 0º 1stMTPJ angle. The clear predominance of a central-shift pattern, at the expense of a medial-shift, occurred with the largest (20º) 1stMTPJ angle among girls. Additionally, the BMI distributions associated with 1stMTPJ angle characteristics showed opposite trends between the sexes. CONCLUSIONS: Valgus alignment of 1stMTPJ among adolescents were associated with limitations in weight-shifting freedom of the foot during walking, that could be involved in maintaining balance. An 1stMTPJ angle of 20º, where distinct limitations were observed, might serve as a criterion of HV pathology.

Influence of short-term inertial training on swimming performance in young swimmers.

The aim of this study was to evaluate the influence of dry-land inertial training (IT) on muscle force, muscle power, and swimming performance. Fourteen young, national-level, competitive swimmers were randomly divided into IT and control (C) groups. The experiment lasted four weeks, during which time both groups underwent their regular swimming training. In addition, the IT group underwent IT using the Inertial Training Measurement System (ITMS) three times per week. The muscle groups involved during the upsweep phase of the arm stroke in front crawl and butterfly stroke were trained. Before and after training, muscle force and power were measured under IT conditions. Simultaneously with the biomechanical measurements on the ITMS, the electrical activity of the triceps brachii was registered. After four weeks of training, a 12.8% increase in the muscle force and 14.2% increase in the muscle power (p < .05) were noted in the IT group. Moreover, electromyography amplitude of triceps brachii recorded during strength measurements increased by 22.7% in the IT group. Moreover, swimming velocity in the 100 m butterfly and 50 m freestyle improved significantly following the four weeks of dry-land IT (-1.86% and -0.76%, respectively). Changes in the C group were trivial. Moreover, values of force and power registered during the ITMS test correlated negatively with the 100 m butterfly and 50 m freestyle swimming times (r value ranged from -.80 to -.91). These results suggest that IT can be useful in swimming practice.

Impact of Inertial Training on Strength and Power Performance in Young Active Men.

Naczk, M, Naczk, A, Brzenczek-Owczarzak, W, Arlet, J, and Adach, Z. Impact of inertial training on strength and power performance in young active men. J Strength Cond Res 30(8): 2107-2113, 2016-This study evaluated how 5 weeks of inertial training using 2 different loads influenced strength and power performance. Fifty-eight male physical education students were randomly divided into training and control groups. The 2 training groups (T0 and T10) performed inertial training 3 times per week for 5 weeks using the new Inertial Training and Measurement System (ITMS). Each training session included 3 exercise sets involving the knee extensors muscles. The T0 group used only the mass of the ITMS flywheel (19.4 kg), whereas the T10 group had an additional 10 kg on the flywheel. Before and after training, we evaluated maximum force and power of knee extensors muscles, countermovement jump (CMJ), squat jump (SJ), maximal power output achieved during ergometer test PVT, electromyography of quadriceps, and muscle mass. In T0 and T10, respectively, ITMS training induced significant increases in muscle force (25.2 and 23.3%), muscle power (33.2 and 27%), CMJ (3.8 and 6.7%), SJ (2.2 and 6.1%), PVT (8 and 7.4%), and muscle mass (9.8 and 15%). The changes did not significantly differ between T0 and T10. A 16% significant increase of electromyography amplitude (quadriceps muscle) was noted only in T0. The novel ITMS training method is effective for improving muscular strength and power. Improvements in PVT, CMJ, and SJ indicate that the increased strength and power elicited by ITMS training can translate to improvements in sport performance. The ITMS training can also be useful for building muscle mass.

Efficacy of inertial training in elbow joint muscles: influence of different movement velocities.

BACKGROUND: The aim of this study was to evaluate the influence of inertial training performed with different movement velocities on elbow flexor and extensor strength and power. METHODS: Thirty-eight male physical education students were divided into training and control groups. The two training groups performed inertial training three times per week for five weeks using the Inertial Training Measurement System. Elbow joint flexors and extensors were trained using different maximal movement velocities: 7.50 rad·s(-1) in the faster (TF) group and 5.76 rad·s(-1) in the slower (TS) group. Before and after training, we evaluated maximum force and power of elbow flexors and extensors muscles under training conditions, maximum torque and power of elbow flexors and extensors muscles under isokinetic conditions and maximal power output achieved during upper body Ergometer Test. RESULTS: Training induced significant increases in elbow flexor force (28.4% in TF and 13.7% in TS) and power (37.7% in TF and 12.4% in TS) measured under training conditions. However, changes in the elbow flexors in the TF group were greater than in the TS group. Elbow extensor force and power measured under inertial conditions increased significantly only in the TF group; 12.5% and 21.1%, respectively. Moreover, the EMG amplitude of the biceps brachii and triceps brachii and upper limb muscle mass increased in both training groups. Measurements made under isokinetic conditions indicated that torque and power improved only in the elbow flexors, no changes in maximal power output were observed during the upper limb Ergometer Test. CONCLUSIONS: The short-term inertial training resulted in significant elbow muscles strength and power improvements. ITMS training induced also the increase of upper limbs muscle mass and the increase of EMG activity of muscles during flexion and extension of elbow. Moreover, greater movement velocities seem to be a benefit for strength and power enhancement. However, further studies are needed to confirm this suggestion.

Training effectiveness of the inertial training and measurement system.

The purpose of this study was to evaluate the efficacy of inertial training with different external loads using a new original device - the Inertial Training and Measurement System (ITMS). Forty-six physical education male students were tested. The participants were randomly divided into three training groups and a control group (C group). The training groups performed inertial training with three different loads three times weekly for four weeks. The T0 group used only the mass of the ITMS flywheel (19.4 kg), the T5 and T10 groups had an additional 5 and 10 kg on the flywheel, respectively. Each training session included three exercise sets involving the shoulder joint adductors. Before and after training, the maximal torque and power were measured on an isokinetic dynamometer during adduction of the shoulder joint. Simultaneously, the electromyography activity of the pectoralis major muscle was recorded. Results of the study indicate that ITMS training induced a significant increase in maximal muscle torque in the T0, T5, T10 groups (15.5%, 13.0%, and 14.0%, respectively). Moreover, ITMS training caused a significant increase in power in the T0, T5, T10 groups (16.6%, 19.5%, and 14.5%, respectively). The percentage changes in torque and power did not significantly differ between training groups. Electromyography activity of the pectoralis major muscle increased only in the T0 group after four weeks of training. Using the ITMS device in specific workouts allowed for an increase of shoulder joint adductors torque and power in physical education students.

Estimation of the efficacy of inertial training in older women.

This study aimed to estimate the efficacy of inertial training in older women using the Inertial Training and Measurement System (ITMS), an original device. Forty-five active women age 53-74 yr performed inertial training with 2 different loads (0 or 5 kg) 3 times weekly for 4 wk. Training sessions consisted of exercises involving the shoulder muscles of the dominant and nondominant arms. The maximal torque and power developed by the dominant and nondominant arms in the 0-kg and 5-kg groups were significantly greater after 4 wk of inertial training (with the exception of torque for the nondominant arm in the 5-kg group; p > .05). Thus, short-term training using the ITMS is efficacious and can be used in older women to improve strength and power. However, ITMS training-induced changes in older women are greater after application of smaller external loads.

Gait functional assessment: Spatio-temporal analysis and classification of barefoot plantar pressure in a group of 11-12-year-old children.

Analysis of pedobarographical data requires geometric identification of specific anatomical areas extracted from recorded plantar pressures. This approach has led to ambiguity in measurements that may underlie the inconsistency of conclusions reported in pedobarographical studies. The goal of this study was to design a new analysis method less susceptible to the projection accuracy of anthropometric points and distance estimation, based on rarely used spatio-temporal indices. Six pedobarographic records per person (three per foot) from a group of 60 children aged 11-12 years were obtained and analyzed. The basis of the analysis was a mutual relationship between two spatio-temporal indices created by excursion of the peak pressure point and the center-of-pressure point on the dynamic pedobarogram. Classification of weight-shift patterns was elaborated and performed, and their frequencies of occurrence were assessed. This new method allows an assessment of body weight shift through the plantar pressure surface based on distribution analysis of spatio-temporal indices not affected by the shape of this surface. Analysis of the distribution of the created index confirmed the existence of typical ways of weight shifting through the plantar surface of the foot during gait, as well as large variability of the intrasubject occurrence. This method may serve as the basis for interpretation of foot functional features and may extend the clinical usefulness of pedobarography.