Additional Information - The impact of Altitude on Perfomance of Football Players
Playing at high altitudes
Football is a global sport played year-round across varying environments, meaning players are frequently exposed to environmental stressors such as temperature and altitude, which can significantly impact performance (Draper et al., 2023). High altitude, in particular, poses primarily physiological challenges for athletes and due to this FIFA initially banned international matches from being played above 2,500 meters (8,200 feet) citing player health and the potential distortion of competition outcomes (BBC News, 2007).
This decision was controversial, especially in high altitude countries and as a result, FIFA later revised the rule, allowing matches at high altitude provided players had sufficient time to acclimatise—one week for altitudes above 2,500 meters and 15 days for altitudes above 3,000 meters (BBC News, 2008). This decision was made based on evidence that the effects of high altitude despite being more pronounced initially, can lessen with acclimatisation (Levine, Stray‐Gundersen & Mehta, 2008). Now while these acclimatisation guidelines are ideal, experts acknowledged that due to the hectic football calendar, extended periods of acclimatisation are unrealistic to most (D’Hooghe, 2013).
However, in the current data set, there is no information on how long players had to acclimatise before each match. This limitation suggests that other variables—such as adequate/inadequate acclimatisation time—could have influenced the results and should be considered when interpreting findings related to altitude performance.
So why would altitude impact RPE, particularly breathing
At high altitudes, lower oxygen availability reduces aerobic exercise capacity, resulting in decreased maximal oxygen uptake (VO₂max), greater perceived exertion, and prolonged recovery (Levine, Stray‐Gundersen & Mehta, 2008). The body compensates for hypoxia through elevated breathing and heart rates, yet oxygen delivery to muscles remains insufficient, negatively impacting performance (Gore et al., 2008).
A study by Aliverti et al. (2011) found that the RPE Breathe during exercise is directly related to how hard the breathing muscles are working, regardless of altitude or oxygen availability. In other words, at high altitudes, people reported the same breathing effort if the workload on their breathing muscles remained constant. The study was conducted on healthy but non-athletic individuals, meaning the findings may not apply to trained athletes, who may experience different responses due to changes in VO₂max at altitude. Additionally, the small sample size of only 10 participants limits the generalisability of the results. The group also had varying fitness levels, potentially influenced by age or training history, which may have affected the outcomes. This suggests that results may differ for elite athletic populations.
Fulton et al. (2018) conducted a study exploring how trained distance runners maintain a breathing pattern synced with their stride, known as locomotor-respiratory coupling. The study found that even when running at a simulated moderate altitude the runner did need to breathe more frequently due to reduced oxygen but were still able to coordinate their breathing with their steps (Fulton et al., 2018). Fulton et al. (2018) suggests that their training helps them adapt their breathing efficiently, potentially conserving energy. These finding may not be applicable to footballers due to the sustained aerobic nature of endurance running, unlike football which has aerobic/anaerobic activity, with periods of high intensity and short, rapid recovery. It is also simulated altitude which may leave out other environmental variables impacting performance.
Nassis (2013) conducted an observational study used secondary data to examine the effects of altitude on football performance. Nassis (2013) states that while lab studies consistently show that altitude impairs endurance due to reduced oxygen availability, there is limited research on its real-world impact in football and other team sports. Nassis (2013) goes on to conclude that interestingly, the negative effects of higher altitude on VO2max, tend to be more pronounced in well-trained athletes, who may experience greater perceived effort and fatigue when competing at altitude compared to sea level. While this is not the strongest evidence coming from a collection of general articles, the author does point out the high volume of laboratory-based research on altitude compared to real world research, particularly around football, despite FIFA’s previous health concerns.
Substitution reasoning
Substitutions that are made in the second half of a match are usually done to counteract player fatigue, and can be influenced by other factors such as match status, opposition strength, and location (Hills et al., 2018l; Gómez et al., 2016),
Data was extracted for RPE Breath and RPE Legs, comparing those who played fewer than 70 minutes with those who played more than 70 minutes during a match. The aim was to determine whether these data could be utilised to inform and optimise substitution strategies.
The available data reveals minimal difference in RPE (both for legs and breathing) between players who played longer or less than 70 minutes. This suggests that RPE levels may not significantly guide substitution decisions or affect strategic planning, even in higher altitudes.
Silva and Swartz, (2016) in their analysis of substitution times based on data from the 2010 world cup and the 2009/10 season from 4 top football leagues in Europe and found no distinct period in the second half where substitutions provide a clear performance benefit. This would align with the results from the data collected. There is a need however for more refined, data-driven decision-making support, particularly when optimising substitution strategies to enhance overall team performance (Van Roy et al., 2023).
Number of observations and how it impacts the reliability of results.
All days
The data indicates that there are significantly fewer observations at moderate altitude compared to sea level, which would be likely in real-life scenarios where fewer teams play at high altitudes. Across all days in the data, there are approximately 74.31% fewer observations at moderate altitude compared to sea level. (see figure 1)
Figure 1
| Altitude Code | Number of Observations |
|---|---|
| sea | 109 |
| low | 73 |
| mod | 28 |
Match day only
For match days only, the difference is still substantial, with approximately 61.90% fewer observations at moderate altitude compared to sea level. (see figure 2)
Figure 2
| Altitude Code | Number of Observations |
|---|---|
| sea | 21 |
| low | 13 |
| mod | 8 |
Challenges in data collection
On of the biggest challenges in sports science research is the reliance on small sample sizes, which undermines the replicability and generalisability of findings, small sample sizes can also reduce the likelihood of detecting small, but meaningful effects (Mesquida et al., 2022; Schweizer and Furley, 2016). Collecting data from larger cohorts enhances the accuracy and reliability of research findings by minimising the impact of individual variability, making results more representative of true population values (Hecksteden et al., 2022).
Sports science studies conducted with small sample sizes could be comparable to the small number of observations recorded at moderate altitude in this data set, without football teams playing an equal number of matches at sea level, low and moderate altitude it is difficult to achieve reliable results on the impact of altitude on the perceived rate of exertion.
References:
Abbott, H. and Taber, C., (2021). ‘How to collect rating of perceived exertion to monitor athlete training load’. Journal of Physical Education, Recreation & Dance, 92(9), pp.5-10.
Aliverti, A., Kayser, B., Mauro, A.L., Quaranta, M., Pompilio, P., Dellacà, R.L., Ora, J., Biasco, L., Cavalleri, L., Pomidori, L. and Cogo, A., (2011). ‘Respiratory and leg muscles perceived exertion during exercise at altitude’. Respiratory physiology & neurobiology, 177(2), pp.162-168.
BBC News (2008) Fifa suspends altitude match ban. Available at: http://news.bbc.co.uk/1/hi/world/americas/7422293.stm (Accessed: 23 April 2025).
D’Hooghe, M., (2013). ‘Football and altitude: a FIFA vision’. British Journal of Sports Medicine, 47(Suppl 1), p.i1. Available at: https://doi.org/10.1136/bjsports-2013-093006
Draper, G., Wright, M.D., Ishida, A., Chesterton, P., Portas, M. and Atkinson, G., (2023). ‘Do environmental temperatures and altitudes affect physical outputs of elite football athletes in match conditions? A systematic review of the ‘real world’studies’. Science and Medicine in Football, 7(1), pp.81-92.
Fulton, T.J., Paris, H.L., Stickford, A.S., Gruber, A.H., Mickleborough, T.D. and Chapman, R.F., (2018). ‘Locomotor-respiratory coupling is maintained in simulated moderate altitude in trained distance runners’. Journal of Applied Physiology, 125(1), pp.1-7.
Gomez, M.A., Lago-Peñas, C. and Owen, L.A., (2016). ‘The influence of substitutions on elite soccer teams’ performance’. International Journal of Performance Analysis in Sport, 16(2), pp.553-568.
Gore, C.J., McSharry, P.E., Hewitt, A.J. and Saunders, P.U., (2008). ‘Preparation for football competition at moderate to high altitude’. Scandinavian journal of medicine & science in sports, 18, pp.85-95.
Hecksteden, A., Kellner, R. and Donath, L., (2022). ‘Dealing with small samples in football research’. Science and medicine in football, 6(3), pp.389-397.
Hills, S.P., Barwood, M.J., Radcliffe, J.N., Cooke, C.B., Kilduff, L.P., Cook, C.J. and Russell, M., (2018). ‘Profiling the responses of soccer substitutes: A review of current literature’. Sports Medicine, 48, pp.2255-2269.
Levine, B.D., Stray‐Gundersen, J. and Mehta, R.D. (2008) ‘Effect of altitude on football performance’, Scandinavian Journal of Medicine & Science in Sports, 18, pp. 76–84.
Lorenzo-Martínez, M., Padrón-Cabo, A., Rey, E. and Memmert, D., (2010). ‘Analysis of physical and technical performance of substitute players in professional soccer’. Research Quarterly for Exercise and Sport, 92(4), pp.599-606.
Mesquida, C., Murphy, J., Lakens, D. and Warne, J., (2022). ‘Replication concerns in sports and exercise science: a narrative review of selected methodological issues in the field’. Royal Society Open Science, 9(12), p.220946.
Nakamura, F.Y., Moreira, A. and Aoki, M.S., (2010). Monitoramento da carga de treinamento: a percepção subjetiva do esforço da sessão é um método confiável. Revista da Educação Física/UEM, 21(1), pp.1-11.
Nassis, G.P., 2013. Effect of altitude on football performance: analysis of the (2010) ‘FIFA World Cup Data’. The Journal of Strength & Conditioning Research, 27(3), pp.703-707.
Reference: BBC News (2007) Fifa bans high-altitude football. Available at: http://news.bbc.co.uk/1/hi/world/americas/6697159.stm (Accessed: 23 April 2025).
Schweizer, G. and Furley, P., (2016). ‘Reproducible research in sport and exercise psychology: The role of sample sizes’. Psychology of Sport and Exercise, 23, pp.114-122.
Silva, R.M. and Swartz, T.B., (2016). ‘Analysis of substitution times in soccer’. Journal of Quantitative Analysis in Sports, 12(3), pp.113-122.
Van Roy, M., Robberechts, P., Yang, W.C., De Raedt, L. and Davis, J., (2023). ‘A Markov framework for learning and reasoning about strategies in professional soccer’. Journal of Artificial Intelligence Research, 77, pp.517-562.