Objective Assessment of Athlete Readiness: Biomarkers for Injury Prevention and Load Management
Latest Data on Biomarkers and Injury Risk
Recent studies confirm that monitoring biochemical blood markers in athletes helps prevent injuries and overtraining, while also optimizing recovery. A meta-analysis of 28 studies involving professional athletes in team sports showed that the dynamics of biomarkers reflect accumulated fatigue and recovery levels, allowing for informed adjustment of training loads without compromising performance. Tracking these parameters helps to “optimize athletic performance while reducing injury risk and overexertion.”
Source: Halson & Peake, 2023 – Sensors, 24(21), 6862
The most established biomarkers include:
Source: Halson & Peake, 2023 – Sensors, 24(21), 6862
It’s important to note that muscle injuries dominate the injury profile of athletes. According to a major multi-year UEFA analysis, muscle strains are the most common type of injury in professional footballers. This makes early detection of muscle overload via blood analysis extremely relevant. Financially, the stakes are high: in the five top European football leagues, total injury-related losses exceeded €700 million per season.
Source: Ekstrand et al., 2013 – The American Journal of Sports Medicine, 41(2)
As a result, clubs are increasingly adopting biochemical monitoring programs to safeguard both their athletes' health and financial investments.
Muscle Damage Markers: CK, AST, LDH and Others
Creatine kinase (CK) is one of the most widely used indicators of muscle damage and fatigue. It is released from muscle cells during intense physical activity and reflects the degree of microtrauma to muscle fibers.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Elevated CK levels after competition have been documented across numerous sports. For example, a 3-day tournament significantly increased CK levels in basketball players. Similarly, a 6-week intensive training period in rugby players led to a marked rise in CK compared to their baseline.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Coaches and sports physicians use these values to evaluate physical stress: an elevated CK level indicates greater muscular strain and the need for recovery.
However, CK interpretation requires an individualized approach. Studies show that baseline CK values can vary significantly among athletes, and so can their physiological response to identical training loads.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Therefore, it is recommended to first determine the personal baseline CK level (using a series of resting measurements) for each athlete and then monitor deviations from that individual reference range. For instance, CK = 500 U/L may be normal for one player, while for another athlete — whose usual value is 200 U/L — the same result may signal overtraining.
Beyond CK, attention should be paid to other enzymes such as aspartate aminotransferase (AST) and lactate dehydrogenase (LDH). While these are traditionally considered liver enzymes, in sports medicine they serve as additional indicators of muscle damage.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
According to sports biochemistry, AST activity in the blood reflects muscle injury as reliably as CK, and can also be used to assess training load.
Furthermore, recent observations in elite football showed that a comprehensive panel including AST, LDH, CK, and creatinine provides a more stable picture of recovery than relying on CK alone.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
AST, LDH, and creatinine also show less inter-individual variability, which makes them more dependable markers for monitoring overtraining risk when assessed in combination.
It is also worth mentioning the CK-MB isoenzyme and α-hydroxybutyrate dehydrogenase (α-HBDH). CK-MB is commonly associated with cardiac muscle damage, but in athletes, mild elevations can also reflect intense muscular strain or microtrauma.
α-HBDH is a subset of the LDH family, and its increase is also observed in muscle damage cases. In one study, researchers simultaneously tracked CK, CK-MB, LDH, and HBDH in football players, confirming their parallel rise after intense matches.
Sources:
Though these markers are used less frequently in day-to-day practice, they provide scientific confirmation of the depth and severity of muscle microtrauma in professional athletes.
Metabolic and Other Readiness Markers
In addition to muscle damage enzymes, an athlete’s biochemical profile includes several metabolic markers that are important for assessing readiness and physiological balance. These include:
How Clubs Are Implementing Biomarker Monitoring
In recent years, biochemical monitoring has become a standard practice in leading sports teams and performance centers. Studies conducted in collaboration with professional clubs demonstrate its practical value and effectiveness.
One especially notable example comes from the Red Bull Athlete Performance Center (Austria), where an integrated monitoring protocol was tested with a youth football team. Over a four-week period, eight players provided daily micro blood samples for measuring CK and cell-free DNA (a marker of cellular breakdown). The system proved feasible and non-intrusive, fitting seamlessly into the team’s training schedule.
Players and coaches accepted the routine positively. Based on the results, coaches adjusted individual loads — for example, players with the highest post-match spikes in CK and DNA received lighter recovery sessions.
Source: Sichting et al., 2022 – Frontiers in Physiology
In Poland, researchers from the University of Szczecin and a medical institute developed a monitoring panel for swimmers, analyzing markers such as ALT, AST, LDH, ALP, creatinine, CRP, ferritin, and bilirubin immediately after training cycles. Their findings showed that post-training changes in AST, LDH, and CK were especially telling, with sprinters showing more pronounced elevations compared to long-distance swimmers.
The authors recommended expanded biochemical screening rather than relying on CK alone, to better reflect full metabolic stress.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
Similar projects are now underway in other countries — from U.S. university teams (football, basketball) where CK and hormone testing are part of pre-season screening, to national sports institutes in China and Russia, which are using biomarker research to guide Olympic preparation.
Rapid Diagnostics: Modern Tools for Elite Sports
Until recently, performing these kinds of biochemical analyses required a full laboratory and significant time. Today, however, portable diagnostic analyzers designed specifically for sports medicine make this process fast, mobile, and efficient.
For example, the Klinogicare Starlab system enables multi-parameter blood analysis in just 7 to 10 minutes, right at the training ground or clinic. Only a few drops of capillary blood are needed, and within minutes the device delivers results for a full panel of critical biomarkers, including:
This level of accessibility means biochemical control can be integrated into the athlete’s daily workflow — whether after training, following a match, or during a routine checkup. Tests can be performed on-site, in a locker room or treatment room, without needing to send samples to a central lab.
Having objective numerical indicators instead of subjective assessments helps eliminate guesswork.
A coach no longer has to rely solely on how a player says they feel. A doctor can point directly to a result and say, for example:
“Your CK is three times your baseline today — that means your body is under stress and you need more recovery.”
Or, conversely:
“All your markers are in range — you’ve recovered well and are ready to train hard.”
This type of evidence-based decision-making boosts trust between players, coaches, and medical staff. And ultimately, it prevents invisible microtraumas from becoming major muscle tears or long-term injuries.
Conclusion: Why Objective Monitoring Is Key to a Long Athletic Career
In today’s world of high-performance sport, where training loads are increasing and competition is intensifying, the integration of scientific methods and modern technologies is no longer optional — it's essential.
Regular monitoring of biochemical markers gives sports doctors and performance staff a powerful preventive medicine tool: the ability to detect issues early — before symptoms appear — and make adjustments accordingly.
Over the past three years, scientific evidence has clearly confirmed this approach. Blood biomarkers are reliable indicators of how an athlete's body is responding to training and recovery, and they can no longer be ignored in elite practice.
Portable equipment like the Klinogicare Starlab analyzer makes this monitoring simple and fast, unlocking new possibilities for on-the-spot decisions based on real data. Whether you're tracking CK, electrolytes, or amylase, objective lab results eliminate uncertainty and support smarter planning.
Timely reductions in training load or an extra day of recovery — based on these results — can prevent a muscle strain or soft tissue injury. And every injury avoided is:
Today, this is not just a trend.
It is a requirement of modern sport, fully supported by peer-reviewed science:
https://www.mdpi.com/1424-8220/24/21/6862
Recent studies confirm that monitoring biochemical blood markers in athletes helps prevent injuries and overtraining, while also optimizing recovery. A meta-analysis of 28 studies involving professional athletes in team sports showed that the dynamics of biomarkers reflect accumulated fatigue and recovery levels, allowing for informed adjustment of training loads without compromising performance. Tracking these parameters helps to “optimize athletic performance while reducing injury risk and overexertion.”
Source: Halson & Peake, 2023 – Sensors, 24(21), 6862
The most established biomarkers include:
- Muscle damage enzymes (particularly creatine kinase, CK),
- Stress hormones (cortisol, testosterone),
- Inflammatory and oxidative stress markers.
Source: Halson & Peake, 2023 – Sensors, 24(21), 6862
It’s important to note that muscle injuries dominate the injury profile of athletes. According to a major multi-year UEFA analysis, muscle strains are the most common type of injury in professional footballers. This makes early detection of muscle overload via blood analysis extremely relevant. Financially, the stakes are high: in the five top European football leagues, total injury-related losses exceeded €700 million per season.
Source: Ekstrand et al., 2013 – The American Journal of Sports Medicine, 41(2)
As a result, clubs are increasingly adopting biochemical monitoring programs to safeguard both their athletes' health and financial investments.
Muscle Damage Markers: CK, AST, LDH and Others
Creatine kinase (CK) is one of the most widely used indicators of muscle damage and fatigue. It is released from muscle cells during intense physical activity and reflects the degree of microtrauma to muscle fibers.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Elevated CK levels after competition have been documented across numerous sports. For example, a 3-day tournament significantly increased CK levels in basketball players. Similarly, a 6-week intensive training period in rugby players led to a marked rise in CK compared to their baseline.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Coaches and sports physicians use these values to evaluate physical stress: an elevated CK level indicates greater muscular strain and the need for recovery.
However, CK interpretation requires an individualized approach. Studies show that baseline CK values can vary significantly among athletes, and so can their physiological response to identical training loads.
Source: Cadegiani et al., 2018 – Sports, 6(1), 19
Therefore, it is recommended to first determine the personal baseline CK level (using a series of resting measurements) for each athlete and then monitor deviations from that individual reference range. For instance, CK = 500 U/L may be normal for one player, while for another athlete — whose usual value is 200 U/L — the same result may signal overtraining.
Beyond CK, attention should be paid to other enzymes such as aspartate aminotransferase (AST) and lactate dehydrogenase (LDH). While these are traditionally considered liver enzymes, in sports medicine they serve as additional indicators of muscle damage.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
According to sports biochemistry, AST activity in the blood reflects muscle injury as reliably as CK, and can also be used to assess training load.
Furthermore, recent observations in elite football showed that a comprehensive panel including AST, LDH, CK, and creatinine provides a more stable picture of recovery than relying on CK alone.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
AST, LDH, and creatinine also show less inter-individual variability, which makes them more dependable markers for monitoring overtraining risk when assessed in combination.
It is also worth mentioning the CK-MB isoenzyme and α-hydroxybutyrate dehydrogenase (α-HBDH). CK-MB is commonly associated with cardiac muscle damage, but in athletes, mild elevations can also reflect intense muscular strain or microtrauma.
α-HBDH is a subset of the LDH family, and its increase is also observed in muscle damage cases. In one study, researchers simultaneously tracked CK, CK-MB, LDH, and HBDH in football players, confirming their parallel rise after intense matches.
Sources:
- Lin et al., 2017 – Journal of Basic and Clinical Physiology and Pharmacology
- DOAJ Open Access Article
Though these markers are used less frequently in day-to-day practice, they provide scientific confirmation of the depth and severity of muscle microtrauma in professional athletes.
Metabolic and Other Readiness Markers
In addition to muscle damage enzymes, an athlete’s biochemical profile includes several metabolic markers that are important for assessing readiness and physiological balance. These include:
- Glucose (GLU): Blood glucose level reflects the body’s energy availability. A level that is too low may indicate incomplete glycogen replenishment or signs of overtraining. Well-recovered athletes typically show normal fasting glucose, while those with chronic energy deficits may exhibit deviations.
- Uric Acid (UA): This is the end product of purine metabolism and serves as a marker of metabolic stress intensity. An increase in UA after prolonged exertion may reflect accelerated ATP and nucleic acid breakdown in working muscle tissue. Some studies link elevated uric acid with oxidative stress and low-grade inflammation, both of which are associated with overtraining.
- Creatinine (CRE): This is a byproduct of creatine phosphate breakdown, directly linked to muscle mass and kidney filtration. Athletes often present with mildly elevated creatinine due to their larger muscle volume. However, an abnormal rise in creatinine beyond the athlete’s baseline may indicate dehydration or excessive muscle catabolism. In football, creatinine is often monitored alongside CK, AST, and LDH as part of recovery screening panels. Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
- Amylase (AMY): A digestive enzyme produced by the pancreas and salivary glands. In sports science, salivary α-amylase is commonly measured as a stress marker, since it correlates with sympathetic nervous system activation. Elevated amylase levels (salivary or serum) may indicate acute stress or dehydration. For example, in combat sports, competitive events led to a spike in salivary α-amylase that mirrored increases in cortisol. Source: López-Pérez, M. A., 2019 – DentistryIQ
- Electrolytes (K⁺, Na⁺, Cl⁻, CO₂): The electrolyte balance is critical for neuromuscular function and preventing cramps. Potassium, sodium, and chloride reflect hydration status and dietary balance. For instance, sodium loss through sweating without proper replenishment increases the risk of cramping and reduces endurance.
- The CO₂ level (total carbon dioxide or bicarbonate concentration) indirectly reflects acid-base balance. A shift in CO₂ may indicate lactate accumulation or metabolic acidosis under heavy load. Monitoring these electrolytes helps medical staff adjust hydration and nutrition strategies to prevent heat-related muscle issues.
How Clubs Are Implementing Biomarker Monitoring
In recent years, biochemical monitoring has become a standard practice in leading sports teams and performance centers. Studies conducted in collaboration with professional clubs demonstrate its practical value and effectiveness.
- Football (Soccer): In a Brazilian professional football club, CK levels were monitored on the second day after each match for four consecutive seasons. A total of 1,656 samples were analyzed. The results showed that CK levels were consistently higher in matches that were followed by muscle injuries. However, CK alone was not sufficient to predict future injuries reliably — the sensitivity was about 56% and specificity around 55%. The researchers concluded that CK alone is not a strong enough screening tool, and emphasized the need for a multi-marker and load-aware approach to injury prediction. Still, the elevated CK in injured players confirmed its relevance as a recovery indicator, and team doctors continued to use it alongside subjective wellness scores and external load data. Source: Barboza et al., 2023 – PubMed
- Ice Hockey and Rugby: High-contact team sports have also integrated routine biochemical tracking. For example, rugby teams perform post-match panels including CK, LDH, and inflammation markers to assess microtrauma severity. Case reports in sports medicine describe how early detection of abnormal CK and LDH levels prompted coaching staff to reduce training loads, effectively preventing more serious injuries.
- Track and Field (Endurance Sports): In individual sports such as long-distance running, biomarkers are used to detect early signs of overload. National team coaches collect capillary blood samples from elite runners prior to key training sessions. When elevated enzyme levels or electrolyte imbalances are detected, training intensity is reduced. This helps to rank athletes by readiness and prevent overreaching before competition.
One especially notable example comes from the Red Bull Athlete Performance Center (Austria), where an integrated monitoring protocol was tested with a youth football team. Over a four-week period, eight players provided daily micro blood samples for measuring CK and cell-free DNA (a marker of cellular breakdown). The system proved feasible and non-intrusive, fitting seamlessly into the team’s training schedule.
Players and coaches accepted the routine positively. Based on the results, coaches adjusted individual loads — for example, players with the highest post-match spikes in CK and DNA received lighter recovery sessions.
Source: Sichting et al., 2022 – Frontiers in Physiology
In Poland, researchers from the University of Szczecin and a medical institute developed a monitoring panel for swimmers, analyzing markers such as ALT, AST, LDH, ALP, creatinine, CRP, ferritin, and bilirubin immediately after training cycles. Their findings showed that post-training changes in AST, LDH, and CK were especially telling, with sprinters showing more pronounced elevations compared to long-distance swimmers.
The authors recommended expanded biochemical screening rather than relying on CK alone, to better reflect full metabolic stress.
Source: Kalinowski et al., 2022 – IJERPH, 19(14), 8580
Similar projects are now underway in other countries — from U.S. university teams (football, basketball) where CK and hormone testing are part of pre-season screening, to national sports institutes in China and Russia, which are using biomarker research to guide Olympic preparation.
Rapid Diagnostics: Modern Tools for Elite Sports
Until recently, performing these kinds of biochemical analyses required a full laboratory and significant time. Today, however, portable diagnostic analyzers designed specifically for sports medicine make this process fast, mobile, and efficient.
For example, the Klinogicare Starlab system enables multi-parameter blood analysis in just 7 to 10 minutes, right at the training ground or clinic. Only a few drops of capillary blood are needed, and within minutes the device delivers results for a full panel of critical biomarkers, including:
- Creatine kinase (CK)
- Aspartate aminotransferase (AST)
- CK-MB
- Lactate dehydrogenase (LDH)
- α-Hydroxybutyrate dehydrogenase (HBDH)
- Glucose
- Amylase
- Creatinine
- Uric acid
- Electrolytes (Potassium, Sodium, Chloride)
- Total CO₂ (bicarbonate level)
This level of accessibility means biochemical control can be integrated into the athlete’s daily workflow — whether after training, following a match, or during a routine checkup. Tests can be performed on-site, in a locker room or treatment room, without needing to send samples to a central lab.
Having objective numerical indicators instead of subjective assessments helps eliminate guesswork.
A coach no longer has to rely solely on how a player says they feel. A doctor can point directly to a result and say, for example:
“Your CK is three times your baseline today — that means your body is under stress and you need more recovery.”
Or, conversely:
“All your markers are in range — you’ve recovered well and are ready to train hard.”
This type of evidence-based decision-making boosts trust between players, coaches, and medical staff. And ultimately, it prevents invisible microtraumas from becoming major muscle tears or long-term injuries.
Conclusion: Why Objective Monitoring Is Key to a Long Athletic Career
In today’s world of high-performance sport, where training loads are increasing and competition is intensifying, the integration of scientific methods and modern technologies is no longer optional — it's essential.
Regular monitoring of biochemical markers gives sports doctors and performance staff a powerful preventive medicine tool: the ability to detect issues early — before symptoms appear — and make adjustments accordingly.
Over the past three years, scientific evidence has clearly confirmed this approach. Blood biomarkers are reliable indicators of how an athlete's body is responding to training and recovery, and they can no longer be ignored in elite practice.
Portable equipment like the Klinogicare Starlab analyzer makes this monitoring simple and fast, unlocking new possibilities for on-the-spot decisions based on real data. Whether you're tracking CK, electrolytes, or amylase, objective lab results eliminate uncertainty and support smarter planning.
Timely reductions in training load or an extra day of recovery — based on these results — can prevent a muscle strain or soft tissue injury. And every injury avoided is:
- preserved player health,
- saved resources for the club,
- and one more chance to win — without sacrificing long-term wellbeing.
Today, this is not just a trend.
It is a requirement of modern sport, fully supported by peer-reviewed science:
https://www.mdpi.com/1424-8220/24/21/6862
References
Halson, S. L., & Peake, J. M. (2023). Athlete Monitoring: Biomarkers for Readiness and Recovery. Sensors, 24(21), 6862.
https://www.mdpi.com/1424-8220/24/21/6862
Ekstrand, J., Hägglund, M., & Waldén, M. (2013). Injury incidence and injury patterns in professional football: the UEFA injury study. The American Journal of Sports Medicine, 41(2), 368–375.
https://journals.sagepub.com/doi/abs/10.1177/0363546512470634
Cadegiani, F. A., et al. (2018). Hormonal and Biochemical Parameters in Elite Athletes. Sports, 6(1), 19.
https://www.mdpi.com/2075-4663/6/1/19
Kalinowski, P., et al. (2022). Biochemical Markers of Recovery in Elite Swimmers. International Journal of Environmental Research and Public Health, 19(14), 8580.
https://www.mdpi.com/1660-4601/19/14/8580
Barboza, S. D., et al. (2023). Creatine Kinase Response and Risk of Muscle Injury in Brazilian Soccer.
https://pubmed.ncbi.nlm.nih.gov/37548364/
Sichting, F., et al. (2022). Longitudinal Monitoring in Youth Soccer Using Biomarkers. Frontiers in Physiology, 13, 1000898.
https://www.frontiersin.org/articles/10.3389/fphys.2022.1000898/full
Lin, C.-H., et al. (2017). Serum Enzyme Activity and Muscle Damage in Football. Journal of Basic and Clinical Physiology and Pharmacology.
https://pubmed.ncbi.nlm.nih.gov/28356830/
López-Pérez, M. A. (2019). The Effects of Endurance Training on Athletes' Oral Health.
https://www.dentistryiq.com/dental-hygiene/student-hygiene/article/16365655/the-effects-of-endurance-training-on-athletes-oral-health
Klinogicare® Starlab POCT Analyzer – Technical Overview.
https://klinogicare.com/starlab-poct-analyzer-sports-ck
https://www.mdpi.com/1424-8220/24/21/6862
Ekstrand, J., Hägglund, M., & Waldén, M. (2013). Injury incidence and injury patterns in professional football: the UEFA injury study. The American Journal of Sports Medicine, 41(2), 368–375.
https://journals.sagepub.com/doi/abs/10.1177/0363546512470634
Cadegiani, F. A., et al. (2018). Hormonal and Biochemical Parameters in Elite Athletes. Sports, 6(1), 19.
https://www.mdpi.com/2075-4663/6/1/19
Kalinowski, P., et al. (2022). Biochemical Markers of Recovery in Elite Swimmers. International Journal of Environmental Research and Public Health, 19(14), 8580.
https://www.mdpi.com/1660-4601/19/14/8580
Barboza, S. D., et al. (2023). Creatine Kinase Response and Risk of Muscle Injury in Brazilian Soccer.
https://pubmed.ncbi.nlm.nih.gov/37548364/
Sichting, F., et al. (2022). Longitudinal Monitoring in Youth Soccer Using Biomarkers. Frontiers in Physiology, 13, 1000898.
https://www.frontiersin.org/articles/10.3389/fphys.2022.1000898/full
Lin, C.-H., et al. (2017). Serum Enzyme Activity and Muscle Damage in Football. Journal of Basic and Clinical Physiology and Pharmacology.
https://pubmed.ncbi.nlm.nih.gov/28356830/
López-Pérez, M. A. (2019). The Effects of Endurance Training on Athletes' Oral Health.
https://www.dentistryiq.com/dental-hygiene/student-hygiene/article/16365655/the-effects-of-endurance-training-on-athletes-oral-health
Klinogicare® Starlab POCT Analyzer – Technical Overview.
https://klinogicare.com/starlab-poct-analyzer-sports-ck