A Review of the Health-Promoting Properties of Spirulina with a Focus on athletes' Performance and Recovery.

Spirulina species are photosynthetic and filamentous bacteria, commonly called 'blue-green microalgae'. Spirulina has a high nutrient content. It contains 60-70% protein with all essential amino acids present, and is rich in several vitamins, minerals, and bioactive compounds. Spirulina is also rich in essential fatty acids, and antioxidants. This rich nutritional content provides to Spirulina several health benefits including antioxidant, anti-inflammatory, immunomodulation, and insulin-sensitizing properties as well as positive effects in various diseases which could be also interesting for athletes. This paper mainly aims to review the interest and effects of Spirulina supplementation in athletes at rest, and in relation to exercise/training. Spirulina's biochemical composition, health properties/effects in humans, and effects in athletes including nutritional status, body composition, physical performance and intense exercise-related disorders were discussed in this review. Literature data showed that Spirulina seems to have positive effects on body composition especially in overweight and obese subjects which could not be the case in other pathologies and athletes. Spirulina appears to be also effective in improving aerobic fitness especially in untrained and moderately trained subjects. Results reported in the literature suggest that Spirulina may improve strength and power performance despite the minor or no significant effects in highly trained subjects. Most studies have shown that Spirulina improves antioxidant status, prevents and accelerates the recovery of exercise-induced lipid peroxidation, muscle damage and inflammation in trained and untrained subjects. Taken together, the results from these studies are encouraging and may demonstrate the potential benefits of Spirulina supplementation in athletes despite methodological differences.

Spirulina supplementation prevents exercise-induced lipid peroxidation, inflammation and skeletal muscle damage in elite rugby players.

BACKGROUND: The present study aimed to examine the effects of spirulina supplementation on pro/antioxidant status, inflammation and skeletal muscle damage markers immediately and 24 h after exhaustive exercise in elite rugby players. METHODS: Seventeen elite male Rugby Union players were randomly assigned to a spirulina (SPI: n = 9) or placebo (PLA: n = 8) group in a double-blind design. Subjects were supplemented with Spirulina platensis (5.7 g day-1 ) or placebo (isoproteic and caloric) for 7 weeks. At baseline and after 7 weeks of supplementation, blood samples were obtained before (T0), immediately after (T1) and 24 h after (T2) exhaustive exercise. The Yoyo Intermittent Recovery Test Level 2 was used as an exhaustive exercise to induce oxidative stress (OS), inflammation and skeletal muscle damage. The studied parameters included pro/antioxidant status markers (superoxide dismutase, glutathione peroxidase, reduced glutathione/glutathione disulphide ratio, oxidised low-density lipoprotein and F2α-isoprostanes [F2-Isop]), inflammation markers (myeloperoxidase and C-reactive protein [CRP]) and skeletal muscle damage markers (lactate dehydrogenase and creatine kinase [CK]). RESULTS: Our results showed that F2-Isop, CRP and CK levels significantly increased at T1 only in the PLA group (p < 0.05, p < 0.05 and p < 0.001, respectively) with no change in the SPI group, which reflects the effect of spirulina to prevent lipid peroxidation, inflammation and skeletal muscle damage induced by exhaustive exercise. Moreover, spirulina supplementation accelerated the return to baseline values given that F2-Isop, CRP and CK levels at T2 were significantly lower than at T0 in the SPI group (p < 0.05, p < 0.01 and p < 0.001, respectively). CONCLUSIONS: Based on the markers used in the present study, our results show that spirulina supplementation potentially prevents exercise-induced lipid peroxidation, inflammation and skeletal muscle damage, and may also accelerate the recovery of some of these markers. Based on our findings, we recommend spirulina supplementation especially for those athletes who do not achieve the recommended antioxidant dietary intake and who perform a high training load aiming to reduce the magnitude of OS, inflammation and skeletal muscle damage, which could help to reduce performance losses and accelerate recovery after training/competitions throughout the season.

Comparison of Cross-Education and Global Training Effects in Adults and Youth After Unilateral Strength Training.

ABSTRACT: Chaouachi, A, Ben Othman, A, Chaouachi, M, Hechmi, A, Farthing, JP, Granacher, U, and Behm, DG. Comparison of cross-education and global training effects in adults and youth after unilateral strength training. J Strength Cond Res 36(8): 2121-2131, 2022-Youth strength training research examining contralateral, homologous (cross-education), and heterologous (global training) effects after unilateral training have provided mixed results and the relationship to adults has not been compared. The objective was to compare adult and youth cross-education and global training effects on dominant and nondominant limb testing. Initially, 15 men and 15 prepubertal boys volunteered for each unilateral chest press (CP), handgrip training, and control groups ( n = 89). Individuals trained their dominant limb 3 times per week for 8 weeks and had their dominant and nondominant limbs tested for CP and leg press 1 repetition maximum (1RM), handgrip, knee extension and flexion, and elbow extension and flexion maximum voluntary isometric contractions (MVICs). Adult CP training gains were significantly greater than youth with lower-body testing ( p = 0.002-0.06), whereas youth CP training gains exceeded adults with upper-body tests ( p = 0.03-0.07). Training specificity was evident with greater CP 1RM increases with CP vs. handgrip training for both youth ( p < 0.0001) and adults ( p < 0.0001). Handgrip training elicited greater gains in handgrip MVICs compared with other strength tests ( p < 0.0001). In conclusion, only contralateral CP 1RM showed a training advantage for unilateral CP over unilateral handgrip training. Adults showed greater gains with lower-body testing, whereas youth showed greater gains with upper-body testing.

Spirulina platensis Provides a Small Advantage in Vertical Jump and Sprint Performance But Does Not Improve Elite Rugby Players' Body Composition.

The present study aimed to examine the effects of Spirulina supplementation on anthropometrical measurements and physical performance in elite rugby players. Twenty-two elite male Rugby Union players (21-36 years old) volunteered to participate in this study. They were randomly assigned to a Spirulina group (SPI: n = 11), or a placebo group (PLA: n = 11) in a double-blind design. Subjects were supplemented with Spirulina platensis (5.7 g/d) or placebo (isoproteic and caloric) for 7 weeks. At baseline (W0) and after 7 weeks of supplementation (W7), the same anthropometric measurements and physical performance test battery were performed. These tests included isokinetic leg strength and power, vertical jump, speed, and aerobic fitness assessment. For anthropometric data, the fat mass percentage was significantly reduced in both groups without significant difference between groups. While both groups exhibited significant improvements for Squat Jump (SJ), Countermovement Jump (CMJ), and 10- and 30-m sprints between W0 and W7, higher percentage improvements with the SPI group did not reach significance. Neither training alone (PLA) nor training associated with Spirulina supplementation affected leg maximal strength and power or aerobic fitness. Seven weeks of Spirulina supplementation in elite rugby players did not improve body composition or substantially increase physical performance. We only observed a non-significant small advantage in vertical jump and sprint performance in the SPI group. Based on the data from this study, Spirulina supplementation has modest effects in elite rugby players during the competitive phase. Further studies are required to verify Spirulina supplementation effects among athletes of different sports, ages, genders, and athletic levels with longer durations and higher dosages.

Taekwondo Anaerobic Intermittent Kick Test: Discriminant Validity and an Update with the Gold-Standard Wingate Test.

The aim of this study was to update the validity of the Taekwondo Anaerobic Intermittent Kick Test compared with the 30-s Wingate anaerobic test as the "Gold-Standard", squat jump and countermovement jump tests. The second objective was to examine whether this new specific test would be able to effectively discriminate between elite taekwondo athletes of different competitive levels. Twenty taekwondo athletes (15 males and 5 females) participated in the validation component, whereas 18 (14 males and 4 females) and 16 (13 males and 3 females) athletes participated in the reliability analysis of the Wingate anaerobic test and jumping tests, respectively. They performed these tests on two separate occasions (i.e., test-retest), in addition to the Taekwondo Anaerobic Intermittent Kick Test. To establish test's discriminatory capability (i.e., construct validity), two subgroups were identified based on their international and national taekwondo performance: 10 elite (8 males and 2 females) and 9 sub-elite (7 males and 2 females) athletes. Wingate anaerobic test and jumping tests performances showed excellent reliability (ICC > 0.90, SEM < 5% for most variables). Significant correlations between Taekwondo Anaerobic Intermittent Kick Test, Wingate anaerobic test, and jumping tests' variables were mostly "large". Elite taekwondo athletes showed greater taekwondo test performances compared with their sub-elite counterparts (p < 0.001). Receiving operating characteristic analysis indicated that the taekwondo specific test was able to effectively discriminate between elite and sub-elite taekwondo athletes. Overall, the findings of the current study support the concurrent validity of the Taekwondo Anaerobic Intermittent Kick Test. In particular, the Taekwondo Anaerobic Intermittent Kick Test showed good ability to effectively discriminate between taekwondo athletes of different competitive levels.

Unilateral Elbow Flexion and Leg Press Training Induce Cross-Education But Not Global Training Gains in Children.

PURPOSE: Whereas cross-education has been extensively investigated with adults, there are far fewer youth investigations. Two studies suggested that children had greater global responses to unilateral knee extensor fatigue and training, respectively, than adults. The objective of this study was to compare global training responses and cross-education effects after unilateral elbow flexion (EFlex) and leg press (LP) training. METHODS: Forty-three prepubertal youths (aged 10-13 y) were randomly allocated into dominant LP (n = 15), EFlex (n = 15) training groups, or a control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pretraining and posttraining for ipsilateral and contralateral 1-repetition maximum LP; knee extensor, knee flexors, elbow flexors; and handgrip maximum voluntary isometric contractions (MVIC), and countermovement jump. RESULTS: In comparison to no significant changes with the control group, dominant elbow flexors training demonstrated significant ( P < .001) improvements only with ipsilateral and contralateral upper body testing (EFlex MVIC [15.9-21.5%], EFlex 1-repetition maximum [22.9-50.8%], handgrip MVIC [5.5-13.8%]). Dominant LP training similarly exhibited only significant ( P < .001) improvements for ipsilateral and contralateral lower body testing (LP 1-repetition maximum [59.6-81.8%], knee extensor MVIC [12.4-18.3%], knee flexor MVIC [7.9-22.3%], and countermovement jump [11.1-18.1%]). CONCLUSIONS: The ipsilateral and contralateral training adaptations in youth were specific to upper or lower body training, respectively.

Dominant and nondominant leg press training induce similar contralateral and ipsilateral limb training adaptations with children.

Cross-education has been extensively investigated with adults. Adult studies report asymmetrical cross-education adaptations predominately after dominant limb training. The objective of the study was to examine unilateral leg press (LP) training of the dominant or nondominant leg on contralateral and ipsilateral strength and balance measures. Forty-two youth (10-13 years) were placed (random allocation) into a dominant (n = 15) or nondominant (n = 14) leg press training group or nontraining control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pre-/post-training for ipsilateral and contralateral 1-repetition maximum (RM) horizontal LP, maximum voluntary isometric contraction (MVIC) of knee extensors (KE) and flexors (KF), countermovement jump (CMJ), triple hop test (THT), MVIC strength of elbow flexors (EF) and handgrip, as well as the stork and Y balance tests. Both dominant and nondominant LP training significantly (p < 0.05) increased both ipsilateral and contralateral lower body strength (LP 1RM (dominant: 59.6%-81.8%; nondominant: 59.5%-96.3%), KE MVIC (dominant: 12.4%-18.3%; nondominant: 8.6%-18.6%), KF MVIC (dominant: 7.9%-22.3%; nondominant: nonsignificant-3.8%), and power (CMJ: dominant: 11.1%-18.1%; nondominant: 7.7%-16.6%)). The exception was that nondominant LP training demonstrated a nonsignificant change with the contralateral KF MVIC. Other significant improvements were with nondominant LP training on ipsilateral EF 1RM (6.2%) and THT (9.6%). There were no significant changes with EF and handgrip MVIC. The contralateral leg stork balance test was impaired following dominant LP training. KF MVIC exhibited the only significant relative post-training to pretraining (post-test/pre-test) ratio differences between dominant versus nondominant LP cross-education training effects. In conclusion, children exhibit symmetrical cross-education or global training adaptations with unilateral training of dominant or nondominant upper leg.

Test-retest reliability and criterion validity of a new Taekwondo Anaerobic Intermittent Kick Test.

BACKGROUND: The aim of this study was to determine the relative and absolute test-retest reliability and criterion validity of a new Taekwondo Anaerobic Intermittent Kick Test (TAIKT). METHODS: Twenty Tunisian elite Taekwondo athletes participated in this study (15 males and 5 females). Participants performed the TAIKT and the Running-based Anaerobic Sprint Test (RAST), twice (test and retest), on separate occasions three-week apart. Peak heart rate (HRpeak), blood lactate concentration [LaÖ¾], and rating of perceived exertion (RPE) were measured during each session. RESULTS: There was no significant difference between the test and retest of TAIKT and RAST for all performances and physiological variables, except for the absolute mean power (Pmean) of RAST. Test-retest results showed that the TAIKT and RAST were reliable. All TAIKT and RAST parameters had an ICC>0.90, SEM<5%, with the smallest worthwhile change slightly higher than SEM, with very small limits of concordance. Strong significant correlations were found between TAIKT and RAST parameters (Ppeak (r=0.81; r=0.70), Pmean (r=0.72; r=0.60) in (W and W·Kg-67 respectively), fatigue index (r=0.81), [LaÖ¾] (r=0.89) and RPE (r=0.78) at P<0.01, and HRpeak (r=0.55, at P<0.05)). CONCLUSIONS: The findings showed that the TAIKT can be considered as a valid and reliable specific test for assessing anaerobic power of Taekwondo athletes.

Combination of Agility and Plyometric Training Provides Similar Training Benefits as Combined Balance and Plyometric Training in Young Soccer Players.

Introduction: Studies that combined balance and resistance training induced larger performance improvements compared with single mode training. Agility exercises contain more dynamic and sport-specific movements compared with balance training. Thus, the purpose of this study was to contrast the effects of combined balance and plyometric training with combined agility and plyometric training and an active control on physical fitness in youth. Methods: Fifty-seven male soccer players aged 10-12 years participated in an 8-week training program (2 × week). They were randomly assigned to a balance-plyometric (BPT: n = 21), agility-plyometric (APT: n = 20) or control group (n = 16). Measures included proxies of muscle power [countermovement jump (CMJ), triple-hop-test (THT)], muscle strength [reactive strength index (RSI), maximum voluntary isometric contraction (MVIC) of handgrip, back extensors, knee extensors], agility [4-m × 9-m shuttle run, Illinois change of direction test (ICODT) with and without the ball], balance (Standing Stork, Y-Balance), and speed (10-30 m sprints). Results: Significant time × group interactions were found for CMJ, hand grip MVIC force, ICODT without a ball, agility (4 m × 9 m), standing stork balance, Y-balance, 10 and 30-m sprint. The APT pre- to post-test measures displayed large ES improvements for hand grip MVIC force, ICODT without a ball, agility test, CMJ, standing stork balance test, Y-balance test but only moderate ES improvements with the 10 and 30 m sprints. The BPT group showed small (30 m sprint), moderate (hand grip MVIC, ICODTwithout a ball) and large ES [agility (4 m × 9 m) test, CMJ, standing stork balance test, Y-balance] improvements, respectively. Conclusion: In conclusion, both training groups provided significant improvements in all measures. It is recommended that youth incorporate balance exercises into their training and progress to agility with their strength and power training.

Within Session Sequence of Balance and Plyometric Exercises Does Not Affect Training Adaptations with Youth Soccer Athletes.

The integration of balance and plyometric training has been shown to provide significant improvements in sprint, jump, agility, and other performance measures in young athletes. It is not known if a specific within session balance and plyometric exercise sequence provides more effective training adaptations. The objective of the present study was to investigate the effects of using a sequence of alternating pairs of exercises versus a block (series) of all balance exercises followed by a block of plyometric exercises on components of physical fitness such as muscle strength, power, speed, agility, and balance. Twenty-six male adolescent soccer players (13.9 ± 0.3 years) participated in an 8-week training program that either alternated individual balance (e.g., exercises on unstable surfaces) and plyometric (e.g., jumps, hops, rebounds) exercises or performed a block of balance exercises prior to a block of plyometric exercises within each training session. Pre- and post-training measures included proxies of strength, power, agility, sprint, and balance such as countermovement jumps, isometric back and knee extension strength, standing long jump, 10 and 30-m sprints, agility, standing stork, and Y-balance tests. Both groups exhibited significant, generally large magnitude (effect sizes) training improvements for all measures with mean performance increases of approximately >30%. There were no significant differences between the training groups over time. The results demonstrate the effectiveness of combining balance and plyometric exercises within a training session on components of physical fitness with young adolescents. The improved performance outcomes were not significantly influenced by the within session exercise sequence.

Evidence of nonlocal muscle fatigue in male youth.

Evidence for nonlocal muscle fatigue (NLMF) has been inconsistent in adults, with no studies investigating youth. The objective was to examine NLMF in youth. Forty-two young males (age, 10-13 years) were tested for maximal voluntary isometric contraction (MVIC) force of the ipsilateral and contralateral knee extensors at 90° and 120° knee flexion, elbow flexors at 90°, handgrip, knee extensor isokinetic torque (300°·s-1 analyzed at 90° and 120° knee flexion), as well as a unilateral countermovement jump (CMJ) and Y Balance test (YBT). Isokinetic fatigue group (n = 15) had unilateral fatigue induced with 10 sets of 20 repetitions of maximal isokinetic knee extensor contractions at 300°·s-1. Isometric fatigue group (n = 15) used 10 repetitions of 6-s knee extensor MVIC whereas the control group (n = 12) were not fatigued. There was no significant difference in the response to the isometric- or isokinetic-fatigue intervention protocols. Main time effects indicated that NLMF was evident with the contralateral knee extensor MVIC at 90° (p = 0.008; 8.9%), knee extensor isokinetic torque at 90° (p < 0.001; 11.4%), and 120° (p = 0.05; 5.4%), CMJ (p = 0.02; 11.5%), handgrip (p = 0.06; 4.5%), elbow flexors (p < 0.001; 7.7%), and YBT (p = 0.001; 5.6%). Ipsilateral NLMF deficits occurred with handgrip (p < 0.001; 7.3%), elbow flexors MVICs (p < 0.001; 10.7%), CMJ (p = 0.02; 12.2%), and YBT (p = 0.002; 3.8%). NLMF with similar relative fatigue-induced deficits of fatigued and nonfatigued limbs suggest that youth fatigue is highly dependent upon the extent of activation or inhibition of the nervous system. Coaches of young athletes might consider developing technical motor skills before fatiguing exercise components, which might hinder the proficiency of their performance.