Acute exercise activates the AHR in peripheral blood mononuclear cells in an intensity-dependent manner.

The kynurenine pathway of tryptophan degradation generates several metabolites such as kynurenine or kynurenic acid that serve as endogenous ligands of the aryl hydrocarbon receptor (AHR). Due to its distinct biological roles particularly modulating the immune system, the AHR is a current therapeutic target across different inflammation-related diseases. Here, we show an acute exercise-induced increase in AHR ligand availability on a systemic level and a kynurenine pathway activation in peripheral blood mononuclear cells (PBMCs). Concurrently, the AHR is activated in PBMCs following acute exercise. Exercise effects on both, kynurenic acid and AHR activation in PBMCs were greater in response to high-intensity interval exercise (50 min., six three-minute intervals á 90% V̇O2peak, and three-minute intervals at 50% V̇O2peak in between) compared to workload-matched moderate intensity continuous exercise (50 min.). In conclusion, these data indicate a novel mechanistic link how exercise modulates the immune system through the kynurenine pathway-AHR axis, potentially underlying exercise-induced benefits in various chronic diseases.

Reliability of the Maximal Lactate Accumulation Rate in Rowers.

The maximal lactate accumulation rate (VLamax) has been linked to lactic anaerobic performance. Hence, accurate and reliable assessment is crucial in sport-specific performance testing. Thus, between-day reliability data of rowing-specific VLamax assessment was examined. Seventeen trained rowers (eight females and nine males; 19.5±5.2 yrs; 1.76±0.08 m; 70.2±8.9 kg; V̇O2max: 54±13 ml/min/kg) performed 20-s sprint tests on two separate days (one week apart) on a rowing ergometer. VLamax, peak lactate concentration, time to peak lactate, and mean rowing power were measured. Good to excellent intraclass correlation coefficients (ICCs), low standard error of measurement (SEM), and acceptable levels of agreement (LoAs; 90% confidence interval) for VLamax (ICC=0.85; SEM=0.02 mmol/L/s; LoA±0.09 mmol/L/s), peak lactate (ICC=0.88; SEM=0.3 mmol/L; LoA±1.4 mmol/l), time to peak lactate (ICC=0.92; SEM=0.1 min; LoA±0.5 min), and mean rowing power (ICC=0.98; SEM=3 W; LoA±39 W) were observed. In addition, VLamax was highly correlated (r=0.96; p≤0.001) to rowing power. Thus, VLamax and sprint performance parameters can be measured highly reliably using this sport-specific sprint test in rowing.

Telemedicine for Patients with Musculoskeletal Pain Lacks High-Quality Evidence on Delivery Modes and Effectiveness: An Umbrella Review.

Background: Musculoskeletal (MSK) pain is the leading cause of disability worldwide. Telemedicine is of growing importance, yet impacts on treatment efficacy remain unclear. Objective: This umbrella review (CRD42022298047) examined the effectiveness of telemedicine interventions on pain intensity, disability, psychological function, quality of life, self-efficacy, and adverse events in MSK pain. Methods: PubMed, SPORTDiscus, Cochrane Library, EMBASE, and CINAHL were searched from inception to August 9, 2022, for systematic reviews with meta-analysis, including telemedicine-delivered exercise, education, and psychological interventions, in randomized controlled trials (RCTs). AMSTAR-2 was implemented. Standardized mean differences (SMDs; negative favors telemedicine) were extracted as effect estimates. Results: Of 1,135 records, 20 reviews (RCTs: n = 97, participants: n = 15,872) were included. Pain intensity SMDs were -0.66 to 0.10 for mixed pain (estimates: n = 16), -0.64 to -0.01 for low-back pain (n = 9), -0.31 to -0.15 for osteoarthritis (n = 7), -0.29 for knee pain (n = 1), -0.66 to -0.58 for fibromyalgia (n = 2), -0.16 for back pain (n = 1), and -0.09 for rheumatic disorders (n = 1). Disability SMDs were -0.50 to 0.10 for mixed pain (n = 14), -0.39 to 0.00 for low-back pain (n = 8), -0.41 to -0.04 for osteoarthritis (n = 7), -0.22 for knee pain (n = 1), and -0.56 for fibromyalgia (n = 1). Methodological quality was "critically low" for 17 reviews. Effectiveness tended to favor telemedicine for all secondary outcomes. Conclusions: Primary RCTs are required that compare telemedicine interventions with in-person delivery of the intervention (noninferiority trials), consider safety, assess videoconferencing, and combine different treatment approaches.

Five-Week, Low-Intensity Blood Flow Restriction Rowing Improves V̇ o2 max in Elite Rowers.

ABSTRACT: Held, S, Rappelt, L, Rein, R, Deutsch, J-P, Wiedenmann, T, and Donath, L. Five-week, low-intensity, blood flow restriction rowing improves V̇ o2 max in elite rowers. J Strength Cond Res 38(6): e299-e303, 2024-This controlled intervention study examined the effects of low-intensity rowing with blood flow restriction (BFR) on maximal oxygen uptake (V̇ o2 max), peak power output during ramp testing (PPO), and 2000-m time trial performance (P2k). Eleven, highly elite, male rowers (22.1 ± 1.6 years; 92.6 ± 3.8 kg; 1.93 ± 0.04 m; 7.9. ± 2.2 years rowing experience; 20.4 ± 2.0 h·w -1 training volume; 11.9 ± 1.1 session per week) trained 5 weeks without BFR (Base) followed by a 5-week BFR intervention period. BFR of the lower limb was applied through customized elastic wraps. BFR took place 3 times a week (accumulated net pBFR: 60 min·wk -1 ; occlusion per session: 2 times 10 min·session -1 ) and was used exclusively at low intensities (<2 mmol·L -1 ). V̇ o2 max, PPO, and P2k were examined before, between, and after both intervention periods. Bayesian's credible intervals revealed relevantly increased V̇ o2 max +0.30 L·min -1 (95% credible interval: +0.00 to +0.61 L·min -1 ) adaptations through BFR. By contrast, PPO +14 W (-6 to +34 W) and P2k -5 W (-14 to +3 W) were not noticeably affected by the BFR intervention. This study revealed that 15 sessions of BFR application with a cumulative total BFR load of 5 h over a 5-week macrocycle increased V̇ o2 max remarkably. Thus, pBFR might serve as a promising tool to improve aerobic capacity in highly trained elite rowers.

Acute response of biomarkers in plasma from capillary blood after a strenuous endurance exercise bout.

PURPOSE: The present study aims to investigate the acute response of potential exercise-sensitive biomarkers in capillary plasma to an acute incremental running test. In a second step, their concentration was compared to the changes in the venous serum. METHODS: Thirty-seven active young female and male adults completed a VO2max ramp test on a treadmill. Before and after exercise, capillary blood from the earlobe and venous blood were taken and synchronized. Concentrations of Interleukin- (IL-) 1ß, IL-1ra, IL-6, IL-8, IL-17A, Interferon (IFN)-y, CC-chemokine ligand (CCL)-2, Matrix metallopeptidase (MMP)-9, Secreted protein acidic and rich in cysteine (SPARC), Cluster of differentiation (CD)163, S100 Ca2+ -binding protein (S100) A8, S100A9, S100B, Brain-derived neurotrophic factor (BDNF), and Myeloperoxidase (MPO) were determined by magnetic bead-based multiplex assay. RESULTS: Capillary plasma concentrations of IL-1ß, IL-6, IL-8, IL-17A, IFN-y, CCL-2, MMP-9, SPARC, CD163, S100A9, S100B, and BDNF increased after exercise (p < 0.05). Comparing the values from capillary plasma and venous serum, ICCs classified as good were found for IFN-y (post), while the ICCs for IL-1ß, IL-8, IL-17A, CCL-2, MMP-9 (post), SPARC, and BDNF (post) were classified as moderate. For all other parameters, only weak ICCs were found. CONCLUSION: As in the venous serum, there was an increase in most markers in the capillary plasma. However, acceptable to low associations can be found in the concentration levels of these proteins between the compartments. Thus, this source of blood sampling could find some biomarker applications in sports practice.

Intensity- and time-matched acute interval and continuous endurance exercise similarly induce an anti-inflammatory environment in recreationally active runners: focus on PD-1 expression in Tregs and the IL-6/IL-10 axis.

PURPOSE: Acute exercise elicits a transient anti-inflammatory state during the early recovery period. Since recent studies reported on regimen-specific effects on immune-related humoral factors and cellular subsets, this study compared the effects of intensity- and time-matched acute interval and continuous exercise on peripheral anti-inflammatory cellular and humoral immune parameters with a particular focus on the PD-1 expression in CD4+ regulatory T cells (Tregs). METHODS: Twenty-four recreationally active runners (age: 29.7 ± 4.3 years, BMI: 22.2 ± 2.4, VO2peak: 56.6 ± 6.4 ml × kg-1 × min-1) participated in this crossover RCT. Each subject conducted a moderate continuous (MCE) and a high-intensity interval exercise (HIIE) session in a counterbalanced design. Blood was drawn before, immediately after, and 1 h after exercise. Treg subsets and levels of PD-1 and Foxp3 were assessed by flow cytometry. Serum levels of IL-10 and IL-6 were quantified by ELISA. RESULTS: PD-1 levels on Tregs increased within the recovery period after HIIE (p < .001) and MCE (p <  0.001). Total counts of Tregs (HIIE: p = 0.044; MCE: p = .021), naïve Tregs (HIIE: p  < 0.001; MCE: p  < 0.001), and PD-1+ effector Tregs (eTregs) (HIIE: p = .002) decreased 1 h after exercise. IL-10 increased 1 h after HIIE (p < 0.001) and MCE (p = 0.018), while IL-6 increased immediately after both HIIE (p = 0.031) and MCE (p = 0.021). Correlations between changes in IL-6 and IL-10 (p = 0.017, r = 0.379) and baseline VO2peak and Treg frequency (p = 0.002, r = 0.660) were identified. CONCLUSION: This is the first study that investigates PD-1 expression in circulating Tregs after acute exercise, revealing an increase in PD-1 levels on eTregs during the early recovery period after intensity- and time-matched HIIE and MCE. Future studies are needed to investigate the PD-1 signalosome in eTregs, together with the expression of key effector molecules (i.e., IL-10, TGF-ß, IL-35, CTLA-4) to elucidate PD-1-dependent changes in cellular function. Based on changes in serum cytokines, this study further reveals a regimen-independent establishment of an anti-inflammatory milieu and underpins the role of the IL-6/IL-10 axis.

Jump and Sprint Performance Directly and 24 h After Velocity- vs. Failure-based Training.

The combination of plyometric and resistance training (RT) is frequently used to increase power-related adaptations. Since plyometric training is most effective when athletes are in a well-rested state, the acute effect of RT on plyometric performance should be carefully considered. Thus, 15 highly trained males (23.1±3.5 yrs, 1.80±0.06 m, 79.1±7.9 kg) completed a load- and volume-matched velocity-based RT session with 10% velocity loss (VL10) and traditional 1-repetition maximum-based RT session to failure (TRF) in a randomized order. Repeated sprints (5 × 15 m), countermovement jumps (CMJs), and drop jumps (DJs) were measured before, immediately after, and 24 h after both sessions. Lactate, heart rate, and perceived effort (RPE) were measured. Sprint, CMJ, and DJ revealed significant interaction effects (rANOVA p<0.001, ηp 2≥0.63). Immediately afterward, sprint, DJ, and CMJ were less negatively affected (p≤0.03, SMD≥|0.40|) by VL10 vs. TRF. Sprint and CMJ were already recovered 24 h post-testing and showed no significant differences between TRF and VL10 (p≥0.07, SMD≤|0.21|). Twenty-four hours post-testing, DJs were still reduced during TRF but already recovered during VL10 (p=0.01, SMD=|0.70|). TRF resulted in higher lactate, heart rate, and RPE compared to VL10 (p≤0.019, η p 2≥0.27, SMD≥|0.68|). In conclusion, the non-failure-based VL10 impairs jump and sprint performance less than the failure-based TRF approach, despite matched volume and intensity.

Disagreement between talent scouts: Implications for improved talent assessment in youth football.

Reliable talent identification and selection (TID) processes are prerequisites to accurately select young athletes with the most potential for talent development programmes. Knowledge about the agreement between scouts who play a key role in the initial TID in football is lacking. Therefore, the aim of the present study was to evaluate the agreement within four groups of a total of n = 83 talent scouts during rank assessment of under-11 male youth football players (n = 24, age = 11.0 ± 0.3 years) and to describe scouts' underlying approach to assess talent. Krippendorff's α estimates indicated disagreement of scouts' rankings within all groups of scouts (αA = 0.09, αB = 0.03, αC = 0.05, αD = 0.02). Scouts reported relying mainly on their overall impression when forming their final prediction about a player. Reportings of a consistent, structured approach were less prevalent. Taken together, results indicated that different approaches to TID may be associated with disagreement on selection decisions. In order to overcome disagreement in TID, football organisations are encouraged to establish a more structured process. Future research on the elaboration and benefit of ranking guidelines incorporating decomposed and independently evaluated sub-predictors is recommended to improve the reliability of TID.

Revealing the Mutual Information between Body-Worn Sensors and Metabolic Cost in Running.

Running power is a popular measure to gauge objective intensity. It has recently been shown, though, that foot-worn sensors alone cannot reflect variations in the exerted energy that stems from changes in the running economy. In order to support long-term improvement in running, these changes need to be taken into account. We propose leveraging the presence of two additional sensors worn by the most ambitious recreational runners for improved measurement: a watch and a heart rate chest strap. Using these accelerometers, which are already present and distributed over the athlete's body, carries more information about metabolic demand than a single foot-worn sensor. In this work, we demonstrate the mutual information between acceleration data and the metabolic demand of running by leveraging the information bottleneck of a constrained convolutional neural network. We perform lab measurements on 29 ambitious recreational runners (age = 28 ± 7 years, weekly running distance = 50 ± 25 km, V˙O2max = 60.3 ± 7.4 mL · min-1·kg-1). We show that information about the metabolic demand of running is contained in kinetic data. Additionally, we prove that the combination of three sensors (foot, torso, and lower arm) carries significantly more information than a single foot-worn sensor. We advocate for the development of running power systems that incorporate the sensors in watches and chest straps to improve the validity of running power and, thereby, long-term training planning.

Blood Flow Restricted Cycling Impairs Subsequent Jumping But Not Balance Performance Slightly More Than Non-Restricted Cycling: An Acute Randomized Controlled Cross-Over Trial.

Chronic blood flow restriction (BFR) training has been shown to improve drop jumping (DJ) and balance performance. However, the acute effects of low intensity BFR cycling on DJ and balance indices have not yet been examined. 28 healthy young adults (9 female; 21.8 ± 2.7years; 1.79 ± 0.08m; 73.9 ± 9.5kg) performed DJ and balance testing before and immediately after 20min low intensity cycling (40% of power at maximal oxygen uptake) with (BFR) and without BFR (noBFR). For DJ related parameters, no significant mode × time interactions were found (p ≥ 0.221, ηp 2 ≤ 0.06). Large time effects for DJ heights and the reactive strength index were observed (p < 0.001, ηp 2 ≥ 0.42). Pairwise comparison revealed notably lower values for both DJ jumping height and reactive strength index at post compared to pre (BFR: -7.4 ± 9.4%, noBFR: -4.2 ± 7.4%). No statistically significant mode × time interactions (p ≥ 0.36; ηp 2 ≤ 0.01) have been observed for balance testing. Low intensity cycling with BFR results in increased (p ≤ 0.01; SMD ≥ 0.72) mean heart rate (+14 ± 8bpm), maximal heart rate (+16 ± 12 bpm), lactate (+0.7 ± 1.2 mmol/L), perceived training intensity (+2.5 ± 1.6au) and pain scores (+4.9 ± 2.2au) compared to noBFR. BFR cycling induced acutely impaired DJ performance, but balance performance was not affected, compared to noBFR cycling. Heart rate, lactate, perceived training intensity, and pain scores were increased during BFR cycling.

Effects of Four Weeks of Static vs. Dynamic Bodyweight Exercises with Whole-Body Electromyostimulation on Jump and Strength Performance: A Two-Armed, Randomized, Controlled Trial.

The combination of strength training with complementary whole-body electromyostimulation (WB-EMS) and plyometric exercises has been shown to increase strength and jumping performance in athletes. In elite sport, however, the mesocycles of training are often organized according to block periodization. Furthermore, WB-EMS is often applied onto static strength exercises, which may hamper the transfer into more sport-specific tasks. Thus, this study aimed at investigating whether four weeks of strength training with complementary dynamic vs. static WB-EMS followed by a four-week block of plyometric training increases maximal strength and jumping performance. A total of n = 26 (13 female/13 male) trained adults (20.8 ± 2.2 years, 69.5 ± 9.5kg, 9.7 ± 6.1h of training/w) were randomly assigned to a static (STA) or volume-, load- and work-to-rest-ratio-matched dynamic training group (DYN). Before (PRE), after four weeks (three times weekly) of WB-EMS training (MID) and a subsequent four-week block (twice weekly) of plyometric training (POST), maximal voluntary contraction (MVC) at leg extension (LE), leg curl (LC) and leg press machines (LP) and jumping performance (SJ, Squat Jump; CMJ, counter-movement-jump; DJ, drop-jump) were assessed. Furthermore, perceived effort (RPE) was rated for each set and subsequently averaged for each session. MVC at LP notably increased between PRE and POST in both STA (2335 ± 539 vs. 2653 ± 659N, standardized mean difference [SMD] = 0.528) and DYN (2483 ± 714N vs. 2885 ± 843N, SMD = 0.515). Reactive strength index of DJ showed significant differences between STA and DYN at MID (162.2 ± 26.4 vs. 123.1 ± 26.5 cm·s-1, p = 0.002, SMD = 1.478) and POST (166.1 ± 28.0 vs. 136.2 ± 31.7 cm·s-1, p = 0.02, SMD = 0.997). Furthermore, there was a significant effect for RPE, with STA rating perceived effort higher than DYN (6.76 ± 0.32 vs. 6.33 ± 0.47 a.u., p = 0.013, SMD = 1.058). When employing a training block of high-density WB-EMS both static and dynamic exercises lead to similar adaptations.

Player-labelling as a solution to overcome maturation selection biases in youth football.

The fact that potentially skilled, but biologically later-maturing athletes are less likely to be selected into talent development programmes (TDP) can represent a failure of Talent Identification (TID) in sports. To overcome maturation selection biases, maturation independent TID should be established to include less mature, but talented athletes in TDP more frequently. Using a randomised parallel-group design, this study aimed to evaluate the effect of labelling under-11 (U11) Swiss male youth football players (n = 24, age = 11.0 ± 0.3 years) via maturation-ordered shirt numbers during rank assessment by talent scouts (n = 83, scout experience = 4.8 ± 2.4 years). Following observation of video recorded selection tournaments, player-labelling "informed" scouts were significantly more likely to rank less mature players higher on their player potential, t(81) = 2.57, p = .012, d = -0.6, 95% CI [-1.00, -0.13], than "uninformed" scouts. As altered rankings assisted less mature players, player-labelling may offer a practical and feasible strategy to improve TID by removing possible maturation selection biases. To address maturation selection biases and the potential positive impact of player-labelling more broadly, further research on both male and female athletes in various age categories and sports contexts is recommended.

Effect of Static Stretching, Dynamic Stretching, and Myofascial Foam Rolling on Range of Motion During Hip Flexion: A Randomized Crossover Trial.

ABSTRACT: Siebert, T, Donath, L, Borsdorf, M, and Stutzig, N. Effect of static stretching, dynamic stretching, and myofascial foam rolling on range of motion during hip flexion: A randomized crossover trial. J Strength Cond Res 36(3): 680-685, 2022-Static and dynamic stretching (DS) are commonly used in sports and physical therapy to increase the range of motion (ROM). However, prolonged static stretching (SS) can deteriorate athletic performance. Alternative methods to increase ROM are thus needed. Foam rolling (FR) may initiate muscle relaxation, improve muscular function, physical performance, and ROM. Previous studies that examined effects of FR on ROM did not control for increased tissue compliance or shifted pain threshold. In this study, the isolated influence of altered tissue compliance on ROM after FR, SS, and DS was investigated using a randomized crossover design. Hip flexion ROM at given joint torques before and after SS, DS, and FR was randomly assessed in 14 young male adults (age: 23.7 ± 1.3 years; height: 182 ± 8 cm; body mass: 79.4 ± 6.9 kg). Hip flexion ROM was measured in the sagittal plane with the subjects lying in a lateral position (no gravitational effects on ROM measurements). Surface electromyographic (EMG) analysis of 2 representative hip extensors (M. biceps femoris and M. semitendinosus) was applied to control for active muscle contribution during ROM measurements. Significant increases in ROM for SS (3.8 ± 1.1°; p < 0.001) and DS (3.7 ± 1.8°; p < 0.001) were observed, but not for FR (0.8 ± 3.1°; p = 0.954). Because stretch forces on tendon and muscle tissue during SS and DS predominately act in longitudinal direction, FR induces mainly transversal forces in the muscle tissue. Thus, increased ROM after FR reported in the literature is more likely due to a shift in the pain threshold. These results provide a better understanding of differential loading conditions during SS, DS, and FR for coaches and practitioners.

Effects of Alternating Unilateral vs. Bilateral Resistance Training on Sprint and Endurance Cycling Performance in Trained Endurance Athletes: A 3-Armed, Randomized, Controlled, Pilot Trial.

ABSTRACT: Ji, S, Donath, L, and Wahl, P. Effects of alternating unilateral vs. bilateral resistance training on sprint and endurance cycling performance in trained endurance athletes: A 3-armed, randomized, controlled, pilot trial. J Strength Cond Res 36(12): 3280-3289, 2022-Traditional preparatory resistance training for cyclists mainly relies on simultaneous bilateral movement patterns. This lack of movement specificity may impede transfer effects to specific aerobic and anaerobic requirements on the bike. Hence, this study investigated the effects of resistance training in alternating unilateral vs. simultaneous bilateral movement pattern on strength and anaerobic as well as aerobic cycling performance indices. Twenty-four trained triathletes and cyclists (age: 31.1 ± 8.1 years; V̇ o2 max: 57.6 ± 7.1 ml·min -1 ·kg -1 ) were randomly assigned to either an alternating unilateral (AUL), a simultaneous bilateral (BIL) training group or a control group (CON). Ten weeks of resistance training (4 × 4-10 repetition maximum) were completed by both training groups, although CON maintained their usual training regimen without resistance training. Maximal strength was tested during isometric leg extension, leg curl, and leg press in both unilateral and bilateral conditions. To compare the transfer effects of the training groups, determinants of cycling performance and time to exhaustion at 105% of the estimated anaerobic threshold were examined. Maximal leg strength notably increased in both training groups (BIL: ∼28%; AUL: ∼27%; p < 0.01) but not in CON (∼6%; p > 0.54). A significant improvement in cycling time trial performance was also observed in both training groups (AUL: 67%; BIL: 43%; p < 0.05) but not for CON (37%; p = 0.43). Bilateral group exhibited an improved cycling economy at submaximal intensities (∼8%; p < 0.05) but no changes occurred in AUL and CON (∼3%; p > 0.24). While sprint cycling performance decreased in CON (peak power: -6%; acceleration index: -15%; p < 0.05), improvement in favor of AUL was observed for acceleration abilities during maximal sprinting (20%; d = 0.5). Our pilot data underpin the importance of resistance training independent of its specific movement pattern both for improving the endurance cycling performance and maximal leg strength. Further research should corroborate our preliminary findings on whether sprint cycling benefits favorably from AUL resistance training.

Reliable Peak Power Assessment During Concentric and Flexion-Extension-Cycle Based Rowing Strokes using a Non-Modified Rowing Ergometer.

Accurate assessment of peak rowing power is crucial for rowing-specific performance testing. Therefore, within and between day reliability of a non-modified rowing ergometer was examined. 52 trained male rowers (21.0 ± 2.9 years; 1.89 ± 0.05 m; 83.2 ± 8.2 kg; 2,000-m ergometer Time Trial mean power: 369 ± 57 W) performed (two times 4) isolated concentric rowing strokes (DRIVE) and single flexion-extension cycle (FEC-type) rowing strokes (SLIDE-DRIVE) on two separate days (1 week apart). Good to excellent intraclass correlation coefficients (0.94 ≤ ICC ≤ 1.00), low standard error of measurement (≤ 2.7%), low coefficient of variation (≤ 4.9%), and suitable level of agreements (≤ 30W) for DRIVE and SLIDE-DRIVE indicated a high level of (within and between day) reliability. In addition, SLIDE-DRIVE (423 ± 157 W) revealed remarkably higher rowing power (p ≤ 0.001; ηp2 = 0.601; SMD = 0.34) compared to DRIVE (370 ± 154 W). The non-modified rowing ergometer is considered to be a reliable tool for the peak power assessment during isolated concentric contraction and FEC-type rowing strokes. Notably higher power outputs (compared to an isolated concentric contraction) during FEC rowing may refer to an underlying stretch shortening cycle.

Effects of Movement-Based Mind-Body Interventions on Physical Fitness in Healthy Older Adults: A Meta-Analytical Review.

INTRODUCTION: Declines in physical fitness can notably affect healthy aging of older adults. Multimodal exercise training regimen such as mind-body interventions (MBIs) has been reported to mitigate these aging-related declines of physical function. This meta-analytical review aimed at pooling the effects of MBIs on physical fitness indices compared to active control (AC) and inactive control (IC) conditions in healthy older adults. METHODS: The literature search was conducted in 3 databases using search terms with Boolean conjunctions. Randomized controlled trials applying MBIs focusing on improving physical fitness parameters in healthy seniors over 65 years of age were screened for eligibility. Eligibility and study quality were assessed by 2 researchers using the PEDro scale. Standardized mean differences (SMD) adjusted for small sample sizes (Hedges' g) served as main outcomes for the comparisons of MBIs versus IC and MBIs versus AC. RESULTS: Thirty trials with 2,792 healthy community dwellers (mean age: 71.2 ± 4.7 years) were included. Large overall effects were found for strength (p < 0.001, SMD: 0.87 [90% CI: 0.43, 1.30], I2 = 94%), medium effects were observed for functional mobility (p = 0.009, SMD: 0.55 [90% CI: 0.20, 0.89], I2 = 83%), and small overall effects were found for static balance (p = 0.02, SMD: 0.35 [90% CI: 0.10, 0.60], I2 = 77%), endurance (p = 0.0001, SMD: 0.44 [90% CI: 0.25, 0.62], I2 = 0%), and flexibility (p = 0.003, SMD: 0.46 [90% CI: 0.21, 0.72], I2 = 54%) in favor of MBIs compared to IC. Small effects of strength slightly favoring AC (p = 0.08, SMD: -0.22 [90% CI: -0.43, -0.01], I2 = 52%) were found, whereas static balance moderately improved in favor of MBIs (p < 0.001, SMD: 0.46 [90% CI: 0.16, 0.76], I2 = 73%). DISCUSSION/CONCLUSION: MBIs induce small to moderate effects in relevant domains of physical fitness in healthy older adults. Strength should be better targeted with traditional resistance training routines, whereas balance seems to sufficiently benefit from MBIs. However, large variability between the studies was observed due to differences in methodology, intervention content, and outcomes that affect conclusive evidence.

Limitations of Foot-Worn Sensors for Assessing Running Power.

Running power as measured by foot-worn sensors is considered to be associated with the metabolic cost of running. In this study, we show that running economy needs to be taken into account when deriving metabolic cost from accelerometer data. We administered an experiment in which 32 experienced participants (age = 28 ± 7 years, weekly running distance = 51 ± 24 km) ran at a constant speed with modified spatiotemporal gait characteristics (stride length, ground contact time, use of arms). We recorded both their metabolic costs of transportation, as well as running power, as measured by a Stryd sensor. Purposely varying the running style impacts the running economy and leads to significant differences in the metabolic cost of running (p < 0.01). At the same time, the expected rise in running power does not follow this change, and there is a significant difference in the relation between metabolic cost and power (p < 0.001). These results stand in contrast to the previously reported link between metabolic and mechanical running characteristics estimated by foot-worn sensors. This casts doubt on the feasibility of measuring running power in the field, as well as using it as a training signal.

Acute Leg and Trunk Muscle Fatigue Differentially Affect Strength, Sprint, Agility, and Balance in Young Adults.

ABSTRACT: Roth, R, Donath, L, Zahner, L, and Faude, O. Acute leg and trunk muscle fatigue differentially affect strength, sprint, agility, and balance in young adults. J Strength Cond Res 35(8): 2158-2164, 2021-How important leg or trunk muscles are for balance and sprint performance is still unexplored. Therefore, we separately fatigued the leg and trunk musculature and examined their contribution to strength, balance, sprint, and agility performance. Twenty-four healthy adults (12 women; age 22.9 [SD: 2.6] years; body mass 59 [10] kg; height 1.65 [0.09] m; and 12 men; age 22.7 [3.0] years; body mass 78 [9] kg; height 1.81 [0.06] m; at least 3 training sessions/week for at least 90 minutes) underwent a leg and a trunk fatigue procedure, each of 20-minute duration and a control condition at rest in a randomized order. Each condition was conducted individually on 3 separate days. Isokinetic leg and trunk strength, as well as static and dynamic balance, sprint, agility, and prone plank endurance, were assessed before and after each fatiguing protocol. Before assessment, a familiarization was conducted. Pairwise magnitude-based inference analyses showed likely relevant deterioration in leg (probability >87%; 0.36 < standardized mean differences [SMDs] < 0.92) and trunk (>88%, 0.28 < SMD < 0.74) fatigue procedures for all motor test parameters compared with the control condition, except for the 20-m sprint after the trunk fatigue procedure. Isokinetic strength testing revealed a large loss of strength in leg fatigue (particularly knee extension, 78%, SMD = 0.24) and trunk fatigue (trunk flexion, 100%, SMD = 1.36). Acute fatigue of leg and trunk muscles decreases performance in relevant measures of strength, balance, sprint, and agility. The impact of leg fatigue compared with trunk fatigue was larger in almost all measurements.

Exploring psychosocial mediators of remote physical activity counselling: a secondary analysis of data from a 1-year randomized control trial (Movingcall).

The present study investigated whether psychosocial determinants mediate the effect of a telephone coaching intervention on physical activity levels. Two hundred eighty-eight adults were randomly assigned to a six-month telephone coaching intervention (n = 12 calls) or a control group receiving a single written recommendation. Seven psychosocial determinants as defined in the MoVo model as well as objective and self-reported physical activity levels were measured after 6 and 12 months. Participants also reported which taught intervention strategies (behavior change techniques) they perceived as most useful. Structural equation modeling was used to determine the mediating role of psychosocial determinants. Up to 227 participants with complete data on psychosocial determinants and physical activity were included in the mediation analyses. Compared to the control group, a greater increase in self-reported and objectively assessed physical activity levels was observed the coaching intervention group. The mediation analyses showed that the intervention had a positive effect on self-efficacy, outcome expectations and intention strength after 6 months and on action planning and barrier management after 6 and 12 months. Increases in objectively assessed physical activity after 6 months were mediated by increased barrier management. None of the other psychosocial determinants worked as mediating factors on self-reported or objectively assessed physical activity. The participants perceived 'action planning' and 'problem solving' as the most useful strategies to increase their physical activity levels. Further understanding of working mechanisms of remote physical activity promotion is needed.

Trunk muscle activity during different types of low weighted squat exercises in normal and forefoot standing conditions.

Squats are considered a useful basic exercise for trunk muscle activation. To gain knowledge about trunk muscle activity patterns depending on the barbell position in beginners, we examined squats with low weights in the back, front, and overhead position. METHODS: Twelve healthy adults (6 women/6 men, age: 29.1 (SD 8.0) y, height: 173.4 (6.9) cm, body mass: 70.1 (9.1) kg) randomly performed the three barbell squats in normal and in forefoot standing. Surface electromyography from external (EO) and internal oblique, rectus abdominis, and erector spinae (ES) was recorded. The centre of pressure path length (CoP) and the motion of the lumbar spine were captured. RESULTS: The overhead squat revealed the highest percent muscle activity, where EO (p = 0.009) and ES (p = 0.03) showed the greatest activity. Forefoot standing did not change overall trunk muscle activities (.05< Hedges' g <.29, 0.17 < p < 0.95) although longer CoP path length (.45 < g < 1.3, p < 0.05) was measured. CONCLUSIONS: Squat exercises with low weight are useful to activate trunk muscles. Activity increases with the difficulty of the squat by frontal or overhead loading, but not by standing on the forefoot. The low weighted squat can target well core muscle activity in training with beginners or in rehabilitation.