Immunometabolic Responses to Concurrent Training: The Effects of Exercise Order in Recreational Weightlifters

Network model of skeletal muscle cell signalling predicts differential responses to endurance and resistance exercise training

Exercise-induced muscle adaptations vary based on exercise modality and intensity. We constructed a signalling network model from 87 published studies of human or rodent skeletal muscle cell responses to endurance or resistance exercise in vivo or simulated exercise in vitro. The network comprises 259 signalling interactions between 120 nodes, representing eight membrane receptors and eight canonical signalling pathways regulating 14 transcriptional regulators, 28 target genes and 12 exercise-induced phenotypes. Using this network, we formulated a logic-based ordinary differential equation model predicting time-dependent molecular and phenotypic alterations following acute endurance and resistance exercises. Compared with nine independent studies, the model accurately predicted 18/21 (85%) acute responses to resistance exercise and 12/16 (75%) acute responses to endurance exercise. Detailed sensitivity analysis of differential phenotypic responses to resistance and endurance training showed that, in the model, exercise regulates cell growth and protein synthesis primarily by signalling via mechanistic target of rapamycin, which is activated by Akt and inhibited in endurance exercise by AMP-activated protein kinase. Endurance exercise preferentially activates inflammation via reactive oxygen species and nuclear factor κB signalling. Furthermore, the expected preferential activation of mitochondrial biogenesis by endurance exercise was counterbalanced in the model by protein kinase C in response to resistance training. This model provides a new tool for investigating cross-talk between skeletal muscle signalling pathways activated by endurance and resistance exercise, and the mechanisms of interactions such as the interference effects of endurance training on resistance exercise outcomes.

Acute effects of concurrent muscle power and sport-specific endurance exercises on markers of immunological stress response and measures of muscular fitness in highly trained youth male athletes

PURPOSE

To examine the acute effects of concurrent muscle power and sport-specific endurance exercises order on immunological stress responses, muscular-fitness, and rating-of-perceived-exertion (RPE) in highly trained youth male judo athletes.

METHODS

Twenty male participants randomly performed two concurrent training (CT) sessions; power-endurance and endurance-power. Measures of immune response (e.g., white blood cells), muscular-fitness (i.e., counter-movement-jump [CMJ]), RPE, blood-lactate, and -glucose were taken at different time-point (i.e., pre, mid, post, and post6h).

RESULTS

There were significant time*order interactions for white blood cells, lymphocytes, granulocytes, granulocyte-lymphocyte-ratio, and systemic-inflammation-index. Power-endurance resulted in significantly larger pre-to-post increases in white blood cells and lymphocytes while endurance-power resulted in significantly larger pre-to-post increases in the granulocyte-lymphocyte-ratio and systemic-inflammation-index. Likewise, significantly larger pre-to-post6h white blood cells and granulocytes increases were observed following power-endurance compared to endurance-power. Moreover, there was a significant time*order interaction for blood-glucose and -lactate. Following endurance-power, blood-lactate and -glucose increased from pre-to-mid but not from pre-to-post. Meanwhile, in power-endurance blood-lactate and -glucose increased from pre-to-post but not from pre-to-mid. A significant time*order interaction was observed for CMJ-force with larger pre-to-post decreases in endurance-power compared to power-endurance. Further, CMJ-power showed larger pre-to-mid performance decreases following power-endurance, compared to endurance-power. Regarding RPE, significant time*order interactions were noted with larger pre-to-mid values following endurance-power and larger pre-to-post values following power-endurance.

CONCLUSION

CT induced acute and delayed order-dependent immune cell count alterations in highly trained youth male judo athletes. In general, power-endurance induced higher acute and delayed immunological stress responses compared to endurance-power. CMJ-force and RPE fluctuated during both CT sessions but went back to baseline 6 h post-exercise.

The growing field of immunometabolism and exercise: Key findings in the last 5 years

This perspective review highlights the impact of physical exercise on immunometabolic responses in the past 5 years. Understanding immunometabolism as a part of immunological research is essential. Furthermore, the roles of both acute and chronic effects of physical exercise on health, aging, and chronic diseases in immunometabolic changes should be elaborated. In immune cells, β2 adrenergic signaling stimulates the preferential mobilization of inflammatory phenotypes, such as CD16⁺ monocytes and CD8⁺ T cells, into the bloodstream after a physical exercise session. The mobilization of immune cells is closely related to the availability of energetic substrates for the cell and mechanisms associated with the uptake and oxidation of fatty acids and glucose. These cells, especially senescent T cells, are mobilized to the peripheral tissues and undergo apoptotic signaling, stimulating the creation of a "vacant space" where new cells will be matured and replaced in the circulation. This results in the upregulation of the expression and secretion of anti-inflammatory cytokines (IL-10 and IL-1ra), leading to increased regulatory immune cells that provide immunoregulatory properties. Thus, we suggest that a significant nutrient available to the cell will favor oxidative metabolism, augment ATP production, and consequently maintain the immune cells in their quiescent state, as well as promote rapid activation function. Therefore, based on the studies discussed in this perspective review, we highlight the importance of performing moderate-intensity continuous and high-intensity intermittent aerobic exercises, due to a higher magnitude of energetic demand and release of anti-inflammatory cytokines (IL-6 and IL-10).

Acute Effects of High-Intensity Interval Running on Lower-Body and Upper-Body Explosive Strength and Throwing Velocity in Handball Players

ABSTRACT

Seipp, D, Feuerbacher, JF, Jacobs, MW, Dragutinovic, B, and Schumann, M. Acute effects of high-intensity interval running on lower-body and upper-body explosive strength and throwing velocity in handball players. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this study was to determine the acute effects of handball-specific high-intensity interval training (HIIT) on explosive strength and throwing velocity, after varying periods of recovery. Fourteen highly trained male handball players (age: 25.4 (26.2 ± 4.2) performed HIIT consisting of repeated 15-second shuttle runs at 90% of final running speed (VIFT) to exhaustion. Upper-body and lower-body explosive strength and throwing velocities were measured before and immediately after HIIT, as well as after 6 hours. These tests included 3 repetitions of both bench press and squat exercise at 60% of the 1 repetition maximum (1RM) as well as 3 repetitions of the set shot without run up and jump shot, respectively. Explosive squat performance was significantly reduced at post (-5.48%, p = 0.026) but not at 6 h (-0.24%, p = 1.000). Explosive bench press performance remained statistically unaltered at post (0.32%, p = 1.000) and at 6 hour (1.96%, p = 1.000). This was also observed in the subsequent throws both immediately after (-0.60%, p = 1.000) (-0.31%, p = 1.000) and at 6 h (-1.58%, p = 1.000) (1.51%, p = 0.647). Our data show a reduction in explosive strength of the lower but not upper extremities when preceded by running HIIT. Since throwing velocity was not affected by intense lower-body exercise, combining lower-body HIIT and throwing practice may be of no concern in highly trained handball players.

Inflammatory cytokines and metabolic responses to high-intensity intermittent training: effect of the exercise intensity

To examine the effects of two high-intensity intermittent training (HIIT) programs of varying intensities (100% vs. 110% of maximal aerobic velocity [MAV]) on metabolic, hormonal and inflammatory markers in young men. Thirty-seven active male volunteers were randomly assigned into: HIIT experimental groups (100% MAV [EG₁₀₀, n = 9] and 110% MAV [EG₁₁₀, n = 9]) and a control groups (CG₁₀₀, n = 9 and CG₁₁₀, n = 9). Particpants performed high intesity intermittent exercise test (HIIE) at 100% or 110% MAV. Venous blood samples were obtained before, at the end of HIIE and at 15 min of recovery, and before and after 8 weeks of HIIT programs. After training, Glucose was lower (p < 0.01) in EG₁₀₀ (d = 0.72) and EG₁₁₀ (d = 1.20) at the end of HIIE, and at 15 min recovery only in EG₁₁₀ (d = 0.95). After training, Insulin and Cortisol were lower than before training in EG₁₀₀ and EG₁₁₀ at the end of HIIE (p < 0.001). After HIIT, IL-6 deceased (p < 0.001) in EG₁₀₀ (d = 1.43) and EG₁₁₀ (d = 1.56) at rest, at the end of HIIE (d = 1.03; d = 1.75, respectively) and at 15 min of recovery (d = 0.88;d = 1.7, respectively). This decrease was more robust (p < 0.05) in EG₁₁₀ compared to EG₁₀₀. After HIIT, TNF-α deceased (p < 0.001) in EG₁₀₀ (d = 1.43) and EG₁₁₀ (d = 0.60) at rest, at the end of HIIE (0.71 < d < 0.98) and at 15 min of recovery (0.70 < d < 2.78). HIIT with 110% MAV is more effective in young males on the improvements of some metabolic (Glucose), hormonal (Cortisol) and inflammatory (IL-6) markers at rest, at the end of HIIE and 15 min of recovery than training at 100 % MAV.

Effects of Concurrent Training on 1RM and VO2 in Adults: Systematic Review with Meta-analysis

The purpose of this systematic review was to analyze the effects of concurrent training on one repetition maximum (1RM), maximum oxygen consumption (VO₂max), and peak oxygen consumption (VO₂peak) in healthy adults. The review followed PRISMA recommendations using randomized controlled trials in nine databases. Twenty-one studies met the inclusion criteria, totaling a sample of 796 subjects to perform the meta-analysis. As result, concurrent training provides similar increases in 1RM as strength training for upper limbs (standardized mean difference [SMD]: 0.12; 95% IC: [-0.18; 0.41]; p=0.43) and for the lower limbs (SMD: -0.32; 95% IC: [-0.79; 0.15]; p=0.19). Similarly, no difference was found in the aerobic capacity between the concurrent training vs. aerobic training groups ([SMD - VO₂max]: -0.19; 95% IC: [-0.71; 0.33]; p=0.48 and [SMD - VO₂peak]: -0.24; 95% IC: [-0.57; 0.08]; p=0.14). Based on the results found, we can affirm that a) similar to strength training, concurrent training provides maximum strength development for upper and lower limbs; and b) cardiorespiratory capacity is not impaired by concurrent training in relation to aerobic training, demonstrating the compatibility of the two training sessions.

The Effects of Endurance-Based Skills-Specific Running Loads on Same-Day Resistance-Training Performance in Professional Australian Rules Football Players

Little is known about the effect of preceding endurance-exercise bouts on subsequent resistance-training (RT) performance in team-sport players.

PURPOSE

To examine the effect of prior skills/endurance training and different recovery time periods on subsequent same-day RT performance in professional Australian football players.

METHODS

Sport-specific endurance-running loads (duration [in minutes], total distance [in meters], mean speed [in meters per minute], high-speed running >15 km·h-1, and relative high-speed running [>75% and >85% of maximal velocity]) were obtained for 46 professional Australian football players for each training session across an entire competitive season. RT was prescribed in 3 weekly mesocycles with tonnage (in kilograms) lifted recorded as RT performance. Endurance and RT sessions were interspersed by different recovery durations: ∼20 min and 1, 2, and 3 h. Fixed- and mixed-effect linear models assessed the influence of skills/endurance-running loads on RT performance. Models also accounted for season period (preseason vs in-season) and recovery duration between concurrent training bouts.

RESULTS

An increase in high-speed running and distance covered >75% and >85% of maximal velocity had the greatest reductions on RT performance. In-season total distance covered displayed greater negative effects on subsequent RT performance compared with preseason, while ∼20-min recovery between skills/endurance and RT was associated with greater reductions in RT performance, compared with 1-, 2-, and 3-h recovery.

CONCLUSIONS

Sport-specific endurance-running loads negatively affect subsequent same-day RT performance, and this effect is greater in-season and with shorter recovery durations between bouts.

Order of same-day concurrent training influences some indices of power development, but not strength, lean mass, or aerobic fitness in healthy, moderately-active men after 9 weeks of training

Background

The importance of concurrent exercise order for improving endurance and resistance adaptations remains unclear, particularly when sessions are performed a few hours apart. We investigated the effects of concurrent training (in alternate orders, separated by ~3 hours) on endurance and resistance training adaptations, compared to resistance-only training.

Materials and methods

Twenty-nine healthy, moderately-active men (mean ± SD; age 24.5 ± 4.7 y; body mass 74.9 ± 10.8 kg; height 179.7 ± 6.5 cm) performed either resistance-only training (RT, n = 9), or same-day concurrent training whereby high-intensity interval training was performed either 3 hours before (HIIT+RT, n = 10) or after resistance training (RT+HIIT, n = 10), for 3 d^.wk^-1 over 9 weeks. Training-induced changes in leg press 1-repetition maximal (1-RM) strength, countermovement jump (CMJ) performance, body composition, peak oxygen uptake (V˙O2peak), aerobic power (W˙peak), and lactate threshold (W˙LT) were assessed before, and after both 5 and 9 weeks of training.

Results

After 9 weeks, all training groups increased leg press 1-RM (~24–28%) and total lean mass (~3-4%), with no clear differences between groups. Both concurrent groups elicited similar small-to-moderate improvements in all markers of aerobic fitness (V˙O2peak ~8–9%; W˙LT ~16-20%; W˙peak ~14-15%). RT improved CMJ displacement (mean ± SD, 5.3 ± 6.3%), velocity (2.2 ± 2.7%), force (absolute: 10.1 ± 10.1%), and power (absolute: 9.8 ± 7.6%; relative: 6.0 ± 6.6%). HIIT+RT elicited comparable improvements in CMJ velocity only (2.2 ± 2.7%). Compared to RT, RT+HIIT attenuated CMJ displacement (mean difference ± 90%CI, -5.1 ± 4.3%), force (absolute: -8.2 ± 7.1%) and power (absolute: -6.0 ± 4.7%). Only RT+HIIT reduced absolute fat mass (mean ± SD, -11.0 ± 11.7%).

Conclusions

In moderately-active males, concurrent training, regardless of the exercise order, presents a viable strategy to improve lower-body maximal strength and total lean mass comparably to resistance-only training, whilst also improving indices of aerobic fitness. However, improvements in CMJ displacement, force, and power were attenuated when RT was performed before HIIT, and as such, exercise order may be an important consideration when designing training programs in which the goal is to improve lower-body power.

Short-Time β-Alanine Supplementation on the Acute Strength Performance after High-Intensity Intermittent Exercise in Recreationally Trained Men

(1) Background: We investigated the effects of 28 days of beta-alanine (β-alanine) supplementation on the acute interference effect of high-intensity intermittent exercise (HIIE) on lower-body resistance exercise performance, body composition, and strength when combined with a resistance training program. (2) Methods: Twenty-two males were randomized into: β-alanine supplementation (6.4 g/day) or placebo (6.4 g/day maltodextrin) during 28 days. Total body water, intracellular and extracellular water, fat-free mass (FFM), and fat mass were assessed using bioelectrical impedance. Participants performed 5000-m HIIE (1:1 effort and rest ratio) followed by resistance exercise (four sets of 80% at 45° leg press until muscular failure) at baseline and after 28 days. The resistance training program consisted of three sets of 10 to 12 RM with 90 s of rest, four days per week. (3) Results: For the post-HIIE leg press volume, higher values were observed post-training than pre-training, but no group x time interaction was observed. There was a non-significant trend for an interaction in the FFM change (β-alanine = 2.8% versus placebo = 1.0%, p = 0.072). (4) Conclusion: Twenty-eight days of β-alanine supplementation did not prevent acute strength loss during resistance exercise after high-intensity interval exercise, nor increase strength or hypertrophic adaptations associated with resistance training.

Short-Term High- and Moderate-Intensity Training Modifies Inflammatory and Metabolic Factors in Response to Acute Exercise

Purpose: To compare the acute and chronic effects of high intensity intermittent training (HIIT) and steady state training (SST) on the metabolic profile and inflammatory response in physically active men.

Methods: Thirty recreationally active men were randomly allocated to a control group (n = 10), HIIT group (n = 10), or SST group (n = 10). For 5 weeks, three times per week, subjects performed HIIT (5 km 1-min at 100% of maximal aerobic speed interspersed by 1-min passive recovery) or SST (5 km at 70% of maximal aerobic speed) while the control group did not perform training. Blood samples were collected at fasting (~12 h), pre-exercise, immediately post, and 60 min post-acute exercise session (pre- and post-5 weeks training). Blood samples were analyzed for glucose, non-ester fatty acid (NEFA), and cytokine (IL-6, IL-10, and TNF-α) levels through a three-way analysis (group, period, and moment of measurement) with repeated measures in the second and third factors.

Results: The results showed an effect of moment of measurement (acute session) with greater values to TNF-α and glucose immediately post the exercise when compared to pre exercise session, independently of group or training period. For IL-6 there was an interaction effect for group and moment of measurement (acute session) the increase occurred immediately post-exercise session and post-60 min in the HIIT group while in the SST the increase was observed only 60 min post, independently of training period. For IL-10, there was an interaction for training period (pre- and post-training) and moment of measurement (acute session), in which in pre-training, pre-exercise values were lower than immediately and 60 min post-exercise, in post-training period pre-exercise values were lower than immediately post-exercise and immediately post-exercise lower than 60 min post, it was also observed that values immediately post-exercise were lower pre- than post-training, being all results independently of intensity (group).

Conclusion: Our main result point to an interaction (acute and chronic) for IL-10 showing attenuation post-training period independent of exercise intensity.

Caffeine supplementation affects the immunometabolic response to concurrent training

The aim of the present study was to investigate the effects of caffeine (CAF) and carbohydrate (CHO) intake on strength performance and its metabolic and inflammatory responses during concurrent training. Seven active males ingested a double-placebo (P), CAF (capsule 5 mg/kg) or CHO (20% maltodextrin solution) supplementation before strength exercise. Participants performed three randomized sessions of 5,000-m high-intensity intermittent aerobic exercise at maximal intensity followed by strength exercise, performing after the P, CHO, and CAF intake. The blood samples were collected before (pre) and immediately after concurrent strength exercise (post). We found a similar number of repetitions and total volume in all supplementation groups. There was a main effect of time on glucose, lactate, and interleukin (IL)-6 (P<0.05). When compared the changes between groups (postvalues minus prevalues), there was lower glucose in CAF group when compared to CHO group (CAF= 5.0±10.4 vs. CHO=27.8±20 vs. P=15.1±14, P=0.031) and higher IL-6 levels (CAF=11.9±9.2 vs. CHO=−2.4±1.7 vs. P=4.3± 11.7, P=0.017). There was significant interaction for glucose and lactate (P<0.001). In conclusion, CAF and CHO intake did not improve strength performance during concurrent strength training in active males. However, CAF affected immunometabolic responses.

Modulation of inflammatory response arising from high-intensity intermittent and concurrent strength training in physically active males

The purposes of this study were to determine: (i) the extent of an acute session of high-intensity intermittent exercise (HIIE) followed by a concurrent strength session (Conc) on the increase of systemic inflammatory cytokines and chemokines, and (ii) whether eight weeks of high intensity interval training plus concurrent strength training alters the acute inflammatory response and immune status. Ten recreationally active males (aged 26.9±4.3years) performed two experimental exercise sessions interspersed by eight weeks of HIIT plus concurrent strength training. The experimental exercise session was composed of a 5-km run on a treadmill (1:1 at 100% of maximal aerobic speed (MAS)), and after 10min of passive recovery, back squat exercises were performed (80% 1RM, four sets until exhaustion). Serum samples were collected after fasting, pre-HIIE, post-HIIE, Pre-Conc, Post-Conc, and 30 and 60min post-exercise session. The comparison between both concurrent exercise sessions was performed using repeated measure ANOVA, with the Bonferroni Post-hoc when necessary. Interleukin-6 (IL-6) presented a moment effect (F=6.72; p<0.05), with Post-Conc significantly higher than pre-HIIE, Post-HIIE, and 60min, only a tendency was found between pre-HIIE and post-HIIE (difference=-5.99; p=0.09). MCP-1 and IL-1ra did not present effects for condition, moment, or interaction. Interleukin-10 (IL-10) presented both moment and interaction effects (F=5.31 and 2.50; p=0.005 and 0.036). Pre-Conc and Post-Conc were significantly higher than Pre-HIIE. The interaction between before and after eight weeks of concurrent training probably occurred at Post-Conc (11.42±3.09pgmL^-1 and 8.88±1.29pgmL^-1). In addition, maintenance of immune function was observed. Therefore, HIIE and concurrent strength exercise lead to an increase in cytokines response, but eight weeks of training program promoted anti-inflammatory response after an acute session of concurrent exercise.

High-Intensity Intermittent Exercise and its Effects on Heart Rate Variability and Subsequent Strength Performance

Prupose: To investigate the effects of a 5-km high-intensity interval exercise (HIIE) on heart rate variability (HRV) and subsequent strength performance.

Methods: Nine trained males performed a control session composed of a half-squat strength exercise (4 × 80% of one repetition maximum—1 RM) in isolation and 30-min, 1-, 4-, 8-, and 24-h after an HIIE (1-min at the velocity peak:1-min passive recovery). All experimental sessions were performed on different days. The maximum number of repetitions (MNR) and total weight lifted (TWL) during the strength exercise were registered in all conditions; in addition, prior to each session, HRV were assessed [beat-to-beat intervals (RR) and log-transformed of root means square of successive differences in the normal-to-normal intervals (lnRMSSD)].

Results: Performance in the strength exercise dropped at 30-min (31%) and 1-h (19%) post-HIIE concomitantly with lower values of RR (781 ± 79 ms; 799 ± 134 ms, respectively) in the same recovery intervals compared to the control (1015 ± 197 ms). Inferential analysis did not detect any effect of condition on lnRMSSD, however, values were lower after 30-min (3.5 ± 0.4 ms) and 1-h (3.3 ± 0.5 ms) with moderate and large effect sizes (0.9 and 1.2, respectively) compared with the control condition (3.9 ± 0.4 ms).

Conclusion: Both RR and lnRMSSD seem to be associated with deleterious effects on strength performance, although further studies should be conducted to clarify this association.